Re: [time-nuts] Machining some aluminum help!
Joseph wrote: For _forming_, one needs something very viscous, something that lubricates at very high pressures, at the yield strength of the material being formed. I've had excellent results with STP oil treatment, by itself or with added Tungsten disulfide. I frequently tap under power at 20-150 rpm, using Tapmatic self-reversing tapping heads. Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On 8/7/17 7:36 AM, Joseph Gwinn wrote: On Sat, 29 Jul 2017 22:49:10 -0400, time-nuts-requ...@febo.com wrote: -- Message: 2 Date: Sat, 29 Jul 2017 20:57:56 -0400 From: Scott McGrath To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Machining some aluminum help! Message-ID: Content-Type: text/plain; charset=us-ascii Kerosine is a better tap lube for Aluminum as it is more persistent and less flammable NO. Kerosene is *not* a good lubricant for _forming_ taps. Kerosene (WD-40) and alcohol are good lubricants for _cutting_. For _forming_, one needs something very viscous, something that lubricates at very high pressures, at the yield strength of the material being formed. Like Molybdenum Disulfide or STP? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
I dont want to start a flame war here but I tend to take the recommendations in Machinery's Handbook as the basis for process decisions. for the last 75 years Machinerys Handbook recommend Kerosene as a tapping fluid for Aluminum even for forming taps Btw if anyone here has a machinists tool box that odd rectangular drawer is for your copy of Machinery's Handbook http://new.industrialpress.com/machinery-s-handbook-30th-edition-toolbox.html WD40 should not be used in any machining operation it was initially created for the USAF to remove water (WATER DISPLACER formula 40) from missile parts which had gotten wet and to leave behind a dry lubricant to prevent corrosion and force out water via capillary action Thats why it works on seized fasteners the capillary action gets the lube into the corrosion cells allowing fasteners to move Content by Scott Typos by Siri > On Aug 7, 2017, at 10:36 AM, Joseph Gwinn wrote: > >> On Sat, 29 Jul 2017 22:49:10 -0400, time-nuts-requ...@febo.com wrote: >> >> -- >> >> Message: 2 >> Date: Sat, 29 Jul 2017 20:57:56 -0400 >> From: Scott McGrath >> To: Discussion of precise time and frequency measurement >> >> Subject: Re: [time-nuts] Machining some aluminum help! >> Message-ID: >> Content-Type: text/plain;charset=us-ascii >> >> Kerosine is a better tap lube for Aluminum as it is more persistent >> and less flammable > > NO. Kerosene is *not* a good lubricant for _forming_ taps. > > Kerosene (WD-40) and alcohol are good lubricants for _cutting_. > > For _forming_, one needs something very viscous, something that > lubricates at very high pressures, at the yield strength of the > material being formed. > > Joe Gwinn > > > >> Content by Scott >> Typos by Siri >> >>>> On Jul 29, 2017, at 6:41 PM, Joseph Gwinn wrote: >>>> >>>> On Sat, 29 Jul 2017 12:00:02 -0400, time-nuts-requ...@febo.com wrote: >>>> Send time-nuts mailing list submissions to >>>> time-nuts@febo.com >>>> >>>> Message: 7 >>>> Date: Fri, 28 Jul 2017 14:11:09 -0700 >>>> From: "Gary E. Miller" >>>> To: Discussion of precise time and frequency measurement >>>> >>>> Subject: Re: [time-nuts] Machining some aluminum help! >>>> Message-ID: <20170728141109.71aad...@spidey.rellim.com> >>>> Content-Type: text/plain; charset="utf-8" >>>> >>>> Yo cdel...@juno.com! >>>> >>>> On Fri, 28 Jul 2017 12:46:30 -0700 >>>> wrote: >>>> >>>>> After mounting the tap in the drill >>>>> press and putting a dab of Crisco on the tap I was able to tap each >>>>> hole to a depth of 7/16" as fast as I could turn the handwheel! >>>> >>>> >>>> Cool! >>>> >>>> I suggest you get some real cutting fluid. The threads will be smoother. >>> >>> I second that. What I use is a lubricant wax made by Lenox, the saw >>> maker. It's intended for metal-cutting band saws, but works just >>> splendid for form taps. There are many equivalents. >>> >>> By the way, when drilling aluminum, use denatured alcohol as the >>> cutting fluid. This will prevent aluminum gumming up the cutting edge >>> of the drill. >>> >>> And, as others have mentioned, one does not use the same size drill for >>> forming taps as for cutting taps. The diameter accuracy required can >>> only be achieved by using the correct number (versus fractional) drill >>> bit size. Do not use Chinese drill bits - steel not good enough. US, >>> Japan, Germany et al are OK. >>> >>> Joe Gwinn >>> >>> >>>> RGDS >>>> GARY >>>> > --- > >> >> End of time-nuts Digest, Vol 156, Issue 38 >> ** > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On Sat, 29 Jul 2017 22:49:10 -0400, time-nuts-requ...@febo.com wrote: > > -- > > Message: 2 > Date: Sat, 29 Jul 2017 20:57:56 -0400 > From: Scott McGrath > To: Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts] Machining some aluminum help! > Message-ID: > Content-Type: text/plain; charset=us-ascii > > Kerosine is a better tap lube for Aluminum as it is more persistent > and less flammable NO. Kerosene is *not* a good lubricant for _forming_ taps. Kerosene (WD-40) and alcohol are good lubricants for _cutting_. For _forming_, one needs something very viscous, something that lubricates at very high pressures, at the yield strength of the material being formed. Joe Gwinn > Content by Scott > Typos by Siri > >> On Jul 29, 2017, at 6:41 PM, Joseph Gwinn wrote: >> >>> On Sat, 29 Jul 2017 12:00:02 -0400, time-nuts-requ...@febo.com wrote: >>> Send time-nuts mailing list submissions to >>>time-nuts@febo.com >>> >>> Message: 7 >>> Date: Fri, 28 Jul 2017 14:11:09 -0700 >>> From: "Gary E. Miller" >>> To: Discussion of precise time and frequency measurement >>> >>> Subject: Re: [time-nuts] Machining some aluminum help! >>> Message-ID: <20170728141109.71aad...@spidey.rellim.com> >>> Content-Type: text/plain; charset="utf-8" >>> >>> Yo cdel...@juno.com! >>> >>> On Fri, 28 Jul 2017 12:46:30 -0700 >>> wrote: >>> >>>> After mounting the tap in the drill >>>> press and putting a dab of Crisco on the tap I was able to tap each >>>> hole to a depth of 7/16" as fast as I could turn the handwheel! >>> >>> >>> Cool! >>> >>> I suggest you get some real cutting fluid. The threads will be smoother. >> >> I second that. What I use is a lubricant wax made by Lenox, the saw >> maker. It's intended for metal-cutting band saws, but works just >> splendid for form taps. There are many equivalents. >> >> By the way, when drilling aluminum, use denatured alcohol as the >> cutting fluid. This will prevent aluminum gumming up the cutting edge >> of the drill. >> >> And, as others have mentioned, one does not use the same size drill for >> forming taps as for cutting taps. The diameter accuracy required can >> only be achieved by using the correct number (versus fractional) drill >> bit size. Do not use Chinese drill bits - steel not good enough. US, >> Japan, Germany et al are OK. >> >> Joe Gwinn >> >> >>> RGDS >>> GARY >>> --- > > End of time-nuts Digest, Vol 156, Issue 38 > ** ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Kerosene as the cutting fluid and use Acetone to clean up the kerosene afterwards. __ Clay Autery, KY5G MONTAC Enterprises (318) 518-1389 On 7/29/2017 7:57 PM, Scott McGrath wrote: > Kerosine is a better tap lube for Aluminum as it is more persistent and less > flammable > > Content by Scott > Typos by Siri > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Kerosine is a better tap lube for Aluminum as it is more persistent and less flammable Content by Scott Typos by Siri > On Jul 29, 2017, at 6:41 PM, Joseph Gwinn wrote: > >> On Sat, 29 Jul 2017 12:00:02 -0400, time-nuts-requ...@febo.com wrote: >> Send time-nuts mailing list submissions to >>time-nuts@febo.com >> >> Message: 7 >> Date: Fri, 28 Jul 2017 14:11:09 -0700 >> From: "Gary E. Miller" >> To: Discussion of precise time and frequency measurement >> >> Subject: Re: [time-nuts] Machining some aluminum help! >> Message-ID: <20170728141109.71aad...@spidey.rellim.com> >> Content-Type: text/plain; charset="utf-8" >> >> Yo cdel...@juno.com! >> >> On Fri, 28 Jul 2017 12:46:30 -0700 >> wrote: >> >>> After mounting the tap in the drill >>> press and putting a dab of Crisco on the tap I was able to tap each >>> hole to a depth of 7/16" as fast as I could turn the handwheel! >> >> >> Cool! >> >> I suggest you get some real cutting fluid. The threads will be smoother. > > I second that. What I use is a lubricant wax made by Lenox, the saw > maker. It's intended for metal-cutting band saws, but works just > splendid for form taps. There are many equivalents. > > By the way, when drilling aluminum, use denatured alcohol as the > cutting fluid. This will prevent aluminum gumming up the cutting edge > of the drill. > > And, as others have mentioned, one does not use the same size drill for > forming taps as for cutting taps. The diameter accuracy required can > only be achieved by using the correct number (versus fractional) drill > bit size. Do not use Chinese drill bits - steel not good enough. US, > Japan, Germany et al are OK. > > Joe Gwinn > > >> RGDS >> GARY >> --- >> >> End of time-nuts Digest, Vol 156, Issue 36 >> ** > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On Sat, 29 Jul 2017 12:00:02 -0400, time-nuts-requ...@febo.com wrote: > Send time-nuts mailing list submissions to > time-nuts@febo.com > > Message: 7 > Date: Fri, 28 Jul 2017 14:11:09 -0700 > From: "Gary E. Miller" > To: Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts] Machining some aluminum help! > Message-ID: <20170728141109.71aad...@spidey.rellim.com> > Content-Type: text/plain; charset="utf-8" > > Yo cdel...@juno.com! > > On Fri, 28 Jul 2017 12:46:30 -0700 > wrote: > >> After mounting the tap in the drill >> press and putting a dab of Crisco on the tap I was able to tap each >> hole to a depth of 7/16" as fast as I could turn the handwheel! > > > Cool! > > I suggest you get some real cutting fluid. The threads will be smoother. I second that. What I use is a lubricant wax made by Lenox, the saw maker. It's intended for metal-cutting band saws, but works just splendid for form taps. There are many equivalents. By the way, when drilling aluminum, use denatured alcohol as the cutting fluid. This will prevent aluminum gumming up the cutting edge of the drill. And, as others have mentioned, one does not use the same size drill for forming taps as for cutting taps. The diameter accuracy required can only be achieved by using the correct number (versus fractional) drill bit size. Do not use Chinese drill bits - steel not good enough. US, Japan, Germany et al are OK. Joe Gwinn > RGDS > GARY > --- > > End of time-nuts Digest, Vol 156, Issue 36 > ** ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Nice! Do you mind posting some photos? Thanks. Edésio On Fri, Jul 28, 2017 at 12:46:30PM -0700, cdel...@juno.com wrote: > Well I did some research and found my new best friend! > > If you remember I needed: "I have a square aluminum tube 5" X 5" with a > .25" wall it's 8 1/2" long. > > I need 20 holes in each end tapped for 4/40 and 1/2" deep." > > This for a Rubidium standard I am working on. > > I found all about self forming taps! > > I drilled the 20 1/2" deep holes and then made a handwheel to attach to > the pulley on my drill press. After mounting the tap in the drill press > and putting a dab of Crisco on the tap I was able to tap each hole to a > depth of 7/16" as fast as I could turn the handwheel! > > I then got another 8-32 self forming tap to do the holes for 15 feedthru > capacitors, again as fast as I could turn the handwheel. > > I'm very happy to discover these taps > > Cheers, > > Corby > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Yo cdel...@juno.com! On Fri, 28 Jul 2017 12:46:30 -0700 wrote: > After mounting the tap in the drill > press and putting a dab of Crisco on the tap I was able to tap each > hole to a depth of 7/16" as fast as I could turn the handwheel! Cool! I suggest you get some real cutting fluid. The threads will be smoother. RGDS GARY --- Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 g...@rellim.com Tel:+1 541 382 8588 Veritas liberabit vos. -- Quid est veritas? "If you can’t measure it, you can’t improve it." - Lord Kelvin pgpn3ISOcp_1P.pgp Description: OpenPGP digital signature ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Good even for mild steel too. Best is your good advice to use the drill press to keep the tap aligned. softer aluminum alloys are very "sticky" and demand backing off a turn for almost every turn forward for cutting taps to break the chip. I've found that the 6/32 tap is the most easily broken. sigh. Pay attention, the tap drill is not the same for the forming tap as it is for the cutting tap. Don On 2017-07-28 13:46, cdel...@juno.com wrote: Well I did some research and found my new best friend! If you remember I needed: "I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. I need 20 holes in each end tapped for 4/40 and 1/2" deep." This for a Rubidium standard I am working on. I found all about self forming taps! I drilled the 20 1/2" deep holes and then made a handwheel to attach to the pulley on my drill press. After mounting the tap in the drill press and putting a dab of Crisco on the tap I was able to tap each hole to a depth of 7/16" as fast as I could turn the handwheel! I then got another 8-32 self forming tap to do the holes for 15 feedthru capacitors, again as fast as I could turn the handwheel. I'm very happy to discover these taps Cheers, Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Dr. Don Latham PO Box 404, Frenchtown, MT, 59834 VOX: 406-626-4304 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Machining some aluminum help!
Well I did some research and found my new best friend! If you remember I needed: "I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. I need 20 holes in each end tapped for 4/40 and 1/2" deep." This for a Rubidium standard I am working on. I found all about self forming taps! I drilled the 20 1/2" deep holes and then made a handwheel to attach to the pulley on my drill press. After mounting the tap in the drill press and putting a dab of Crisco on the tap I was able to tap each hole to a depth of 7/16" as fast as I could turn the handwheel! I then got another 8-32 self forming tap to do the holes for 15 feedthru capacitors, again as fast as I could turn the handwheel. I'm very happy to discover these taps Cheers, Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
For popping off the lid, a few threaded holes in the lid would be nice. Insert screws and let them push against the body and push the lid off. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of ed breya Sent: Thursday, May 25, 2017 3:08 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Machining some aluminum help! This is the first time I've looked at time-nuts in about a month, and I noticed the run about this project. I'm very late to the party, but have a few suggestions that may help - if it's not too late. I quickly scanned many of the posts, and agree with many of the ideas. Please forgive if my suggestions are redundant to what's already been said. First, I assume that the aluminum box is a simple extrusion, so it will likely be a soft alloy that will tend to gall horribly with machining - especially bad for anything that needs high precision. With these kinds of material, go big, starting with bigger fasteners. With 1/4" walls, you can easily up it to 6-32 or 8-32, as long as the holes are fairly shallow, and you can jig it up for good centering and plumbness. With 4-40 and blind holes, you're just asking for trouble - especially taking a chance 40 times. The tap drill will be quite skinny, and prone to deform and wander as it goes in, and can easily be snapped off when it stalls due to the galling - and that's just the drilling stage - the tapping will be worse. Bigger threads give you a chance to get it done with fewer fasteners and holes, and much less grief. The thread depth should allow for at least one pitch-diameter of penetration for strength, but preferably two or more, so you don't have to worry about finding exact right screw lengths that won't bottom out. Depending on the thickness of the end plates, you could get down to two or three fasteners per side to hold the small pressure needed. If you're using a drill press, punch mark the hole centers, then use a center drill to make the pilot holes for the tap drill. If you're freehand drilling, put the piece on the floor and drill downward, keeping it as plumb as possible. Definitely use an oil or other lubricant for all the drilling and tapping operations. For sealing, I'd recommend against fancy o-ring features and such - these are also harder to machine cleanly in soft aluminum, and add unnecessary complexity. If the end caps need regular remove and replace operations, then go with a pliable gasket, have more fasteners to get more uniform compression, and make the threads deeper so they'll last longer. If the sealing is one-time, or seldom needs to be broken, I'd recommend using a gasket sealing goop that will work fine with few fasteners and even rough surface finish. My favorite is Permatex #2 "Form-A-Gasket Sealant," which I've used for all sorts of stuff over fifty years (back then it was Radiator Specialties brand). Don't use a silicone goop unless you want to spend a lot of time scraping off the old stuff if it needs to be opened. If you do use a goop, it's a good idea to machine in features for prying the lids off, such as gasket-plane screwdriver slots, or extra tapped through-holes in line with the mounting holes on of the l id. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
That is one reason people have been recommending heilicoils. The drill an tap size is about 30% larger than for #4 screws without the inserts. It is easier to do and when you are done there are stainless female threads that are much stronger. On Thu, May 25, 2017 at 3:57 PM, ed breya wrote: > ..., you can save a lot of grief by using a slightly larger bit than the > standard tap drill. You're not really too concerned with optimal fit and > strength here - it's more about being able to make a whole lot of usable > screw holes without losing too many bits and taps, -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
One thing I forgot to add - if you must use the 4-40 screw size for some reason, you can save a lot of grief by using a slightly larger bit than the standard tap drill. You're not really too concerned with optimal fit and strength here - it's more about being able to make a whole lot of usable screw holes without losing too many bits and taps, or reworking. You can experiment and see what size makes the best tradeoffs. It's amazing sometimes how a little more root clearance can makes things so much nicer - a shallower cut, so less torque on that tiny tap, more room for chip clearing, and better lubing. You can also get deeper threads to compensate for less meat in the thread root. Even the drill bit will have a better chance of survival, since it will be slightly bigger and stronger. Of course, if you go too far, there won't be enough thread - but then you'll have reason to jump to the next size up. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Why not make the enclosure with a round, not square cross section then the end plate can screw in. Only one hole to thread that way. Of course there is plumbing pipe but also stainless steel water bottles, fly rod cases and all kinds of ready made metal enclosures with thread caps that can hold pressure.A stanley wide mouth thermos would be excellent for making a temperature controlled metal enclosure. The vacuum insolation is pretty good, and of course they already hold pressure. On Thu, May 25, 2017 at 2:08 PM, ed breya wrote: > This is the first time I've looked at time-nuts in about a month, and I > noticed the run about this project. I'm very late to the party, but have a > few suggestions that may help - if it's not too late. I quickly scanned many > of the posts, and agree with many of the ideas. Please forgive if my > suggestions are redundant to what's already been said. > > First, I assume that the aluminum box is a simple extrusion, so it will > likely be a soft alloy that will tend to gall horribly with machining - > especially bad for anything that needs high precision. With these kinds of > material, go big, starting with bigger fasteners. With 1/4" walls, you can > easily up it to 6-32 or 8-32, as long as the holes are fairly shallow, and > you can jig it up for good centering and plumbness. With 4-40 and blind > holes, you're just asking for trouble - especially taking a chance 40 times. > The tap drill will be quite skinny, and prone to deform and wander as it > goes in, and can easily be snapped off when it stalls due to the galling - > and that's just the drilling stage - the tapping will be worse. > > Bigger threads give you a chance to get it done with fewer fasteners and > holes, and much less grief. The thread depth should allow for at least one > pitch-diameter of penetration for strength, but preferably two or more, so > you don't have to worry about finding exact right screw lengths that won't > bottom out. Depending on the thickness of the end plates, you could get down > to two or three fasteners per side to hold the small pressure needed. > > If you're using a drill press, punch mark the hole centers, then use a > center drill to make the pilot holes for the tap drill. If you're freehand > drilling, put the piece on the floor and drill downward, keeping it as plumb > as possible. Definitely use an oil or other lubricant for all the drilling > and tapping operations. > > For sealing, I'd recommend against fancy o-ring features and such - these > are also harder to machine cleanly in soft aluminum, and add unnecessary > complexity. If the end caps need regular remove and replace operations, then > go with a pliable gasket, have more fasteners to get more uniform > compression, and make the threads deeper so they'll last longer. If the > sealing is one-time, or seldom needs to be broken, I'd recommend using a > gasket sealing goop that will work fine with few fasteners and even rough > surface finish. My favorite is Permatex #2 "Form-A-Gasket Sealant," which > I've used for all sorts of stuff over fifty years (back then it was Radiator > Specialties brand). Don't use a silicone goop unless you want to spend a lot > of time scraping off the old stuff if it needs to be opened. If you do use a > goop, it's a good idea to machine in features for prying the lids off, such > as gasket-plane screwdriver slots, or extra tapped through-holes in line > with the mounting holes on of the lid. > > Ed > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
This is the first time I've looked at time-nuts in about a month, and I noticed the run about this project. I'm very late to the party, but have a few suggestions that may help - if it's not too late. I quickly scanned many of the posts, and agree with many of the ideas. Please forgive if my suggestions are redundant to what's already been said. First, I assume that the aluminum box is a simple extrusion, so it will likely be a soft alloy that will tend to gall horribly with machining - especially bad for anything that needs high precision. With these kinds of material, go big, starting with bigger fasteners. With 1/4" walls, you can easily up it to 6-32 or 8-32, as long as the holes are fairly shallow, and you can jig it up for good centering and plumbness. With 4-40 and blind holes, you're just asking for trouble - especially taking a chance 40 times. The tap drill will be quite skinny, and prone to deform and wander as it goes in, and can easily be snapped off when it stalls due to the galling - and that's just the drilling stage - the tapping will be worse. Bigger threads give you a chance to get it done with fewer fasteners and holes, and much less grief. The thread depth should allow for at least one pitch-diameter of penetration for strength, but preferably two or more, so you don't have to worry about finding exact right screw lengths that won't bottom out. Depending on the thickness of the end plates, you could get down to two or three fasteners per side to hold the small pressure needed. If you're using a drill press, punch mark the hole centers, then use a center drill to make the pilot holes for the tap drill. If you're freehand drilling, put the piece on the floor and drill downward, keeping it as plumb as possible. Definitely use an oil or other lubricant for all the drilling and tapping operations. For sealing, I'd recommend against fancy o-ring features and such - these are also harder to machine cleanly in soft aluminum, and add unnecessary complexity. If the end caps need regular remove and replace operations, then go with a pliable gasket, have more fasteners to get more uniform compression, and make the threads deeper so they'll last longer. If the sealing is one-time, or seldom needs to be broken, I'd recommend using a gasket sealing goop that will work fine with few fasteners and even rough surface finish. My favorite is Permatex #2 "Form-A-Gasket Sealant," which I've used for all sorts of stuff over fifty years (back then it was Radiator Specialties brand). Don't use a silicone goop unless you want to spend a lot of time scraping off the old stuff if it needs to be opened. If you do use a goop, it's a good idea to machine in features for prying the lids off, such as gasket-plane screwdriver slots, or extra tapped through-holes in line with the mounting holes on of the lid. Ed ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Hi > On May 19, 2017, at 5:35 PM, Chris Albertson > wrote: > > Yes, threaded inserts. There are many kinds but they are used almost > universally for cases where the material to be threaded is soft, like > aluminum. They also eliminate or reduce galvanic corrosion which is an > issue with steel screws in aluminum. (that said, as long as you keep water > away you are OK.) There are some interesting internal studies out of places like Boeing that suggest the “keep moisture away” includes some pretty modest levels of humidity …. It then becomes a question of if you do or do not accept their methods. Bob > Still these inserts are the "class" way to go and will > save some broken taps. > > As for a seal, it is hard to beat o-rings. A proper designed o-ring seal > does not need much clamping pressure as it depends on the pressure inside > to force the ring in place and hold it there. > > On Fri, May 19, 2017 at 12:51 PM, Lincoln wrote: > >> >>> >>> There are a lot of variables involved. Run the screws in and out of the >> aluminum a number of times and >>> the holes will fail first ….There are other gotchas as well. >>> >>> Bob >>> >> >> This is where helicoils come in to play. They are used a lot on the CVD >> furnaces that I used to make parts for. They are not just for un-buggering >> a thread. They would be installed form the get go and could be replaced >> should something gall. >> >> Link >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > -- > > Chris Albertson > Redondo Beach, California > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
I worked on a project like this once. No screws at all. Rather then a 0.1 PSI over pressure. the interior was flush with dry gas then pumped out with to a crude vacuum with a hand pump. Air pressure alone force the cover plate on. OK a couple screws where there just to aid in assembly but the cheap $12 hand pump was good enough. "high vacuum" requires expensive equipment and is a black art but "crude vacuum" is easy, easier then holding a pressure because the forces are pushing the seal together for you. On Thu, May 18, 2017 at 2:46 PM, jimlux wrote: > On 5/18/17 1:34 PM, cdel...@juno.com wrote: > >> Well that generated a lot of advice and thanks for it! >> I think I might do it myself and go with a 1/2" hole depth and 1/4" >> threaded depth. >> I'll get some of that Aluminum Tap magic, some new taps and new drill >> bits. >> Good idea about drilling the end plates first and drilling thru to match. >> Between the end plate and the tube is a gasket that needs to seal >> pressure and moisture tight. That's why I used 5 per side. >> > > I would make the end plate "real thick",with a machined groove for the > o-ring, and use some sort of latches to hold it in place, rather than "lots > 'o screws". Unless you've got a real tight space constraint. How much > pressure do you have to hold? That will determine the clamping force needed > on your gasket (and potentially, on your fasteners). Do you need the full > 4.5x4.5" inside clear space? A 1/4-20 bolt in the corner might be a good > way to go. > > There's also inexpensive surplus vacuum equipment around, as well as run > of the mill plumbing. Unless Steel (stainless or not) isn't an option. > > > > > > >> Will let you know how it turns out. >> >> Cheers, >> >> Corby >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/m >> ailman/listinfo/time-nuts >> and follow the instructions there. >> >> > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Yes, threaded inserts. There are many kinds but they are used almost universally for cases where the material to be threaded is soft, like aluminum. They also eliminate or reduce galvanic corrosion which is an issue with steel screws in aluminum. (that said, as long as you keep water away you are OK.)Still these inserts are the "class" way to go and will save some broken taps. As for a seal, it is hard to beat o-rings. A proper designed o-ring seal does not need much clamping pressure as it depends on the pressure inside to force the ring in place and hold it there. On Fri, May 19, 2017 at 12:51 PM, Lincoln wrote: > > > > > There are a lot of variables involved. Run the screws in and out of the > aluminum a number of times and > > the holes will fail first ….There are other gotchas as well. > > > > Bob > > > > This is where helicoils come in to play. They are used a lot on the CVD > furnaces that I used to make parts for. They are not just for un-buggering > a thread. They would be installed form the get go and could be replaced > should something gall. > > Link > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
We also used helicoils in titanium frames of the supercomputer I used to work with. Meant we could use relatively standard fasteners without fear of falling. On a time nuts related note, I have a u blox GPS-1E that seems to be stuck spewing out in ublox format. With no development sw available (that runs on my Mac), I'm looking for the correct string to send its way to change it back to NMEA. Anyone point me at some docs or know the appropriate string? Thanks! Bob > On May 19, 2017, at 15:51, Lincoln wrote: > > >> >> There are a lot of variables involved. Run the screws in and out of the >> aluminum a number of times and >> the holes will fail first ….There are other gotchas as well. >> >> Bob >> > > This is where helicoils come in to play. They are used a lot on the CVD > furnaces that I used to make parts for. They are not just for un-buggering a > thread. They would be installed form the get go and could be replaced should > something gall. > > Link > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Corby Unless you have the tubing and plates machined flat they will leak as the tubing sides are not guaranteed to be flat and parallel wrt each side and aluminum plate stock is not flat unless you purchase 'tooling plate' which is ground parallel on both sides So creating a seal is problematic at best Content by Scott Typos by Siri > On May 19, 2017, at 4:23 PM, wrote: > > Thanks everyone. > > Not looking for a redesign, just figuring out how to get the holes > drilled and tapped. > > I have come up with a scheme that looks promising and will let you know > how it goes. > > The enclosure only has to hold +.1PSI of dry nitrogen without leaking. > > It will have a pressure sensor inside to allow long term monitoring. > > From the feedback and some research I will be reducing the depth of the > threaded portion. > > Cheers, > > Corby > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Machining some aluminum help!
Thanks everyone. Not looking for a redesign, just figuring out how to get the holes drilled and tapped. I have come up with a scheme that looks promising and will let you know how it goes. The enclosure only has to hold +.1PSI of dry nitrogen without leaking. It will have a pressure sensor inside to allow long term monitoring. >From the feedback and some research I will be reducing the depth of the threaded portion. Cheers, Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
> > There are a lot of variables involved. Run the screws in and out of the > aluminum a number of times and > the holes will fail first ….There are other gotchas as well. > > Bob > This is where helicoils come in to play. They are used a lot on the CVD furnaces that I used to make parts for. They are not just for un-buggering a thread. They would be installed form the get go and could be replaced should something gall. Link ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
To tell the truth I had not worked this out.But I wonder of the screws fail first on they are in aluminum holes with only 1/4 of thread. Which fails depends on the material and the number of engaged threads, But if what you say is right for this case. It strengthens my case for using self threading screws. I try and use these when I can. What you do is center punch the screw location around the end plate. Then glue the end plat in place using blue lock tight. (or even two tiny daps of "Super Glue") then go to the drip pressed drill through the endplate into the edge of the wall and insert one screw. The right size the type screw will cut its own thread as you screw it in. Then drill neither hole and put in another screw. It is imported to place the screw as you drill to keep alignment, even when using the glue. Later take out the screw and break the glue, reassemble. On Thu, May 18, 2017 at 5:13 PM, jimlux wrote: > On 5/18/17 2:36 PM, Chris Albertson wrote: > >> It would be easy to re-design the job for cheaper machining.. Do you >> really need to tap the holes? You might use self taping screws. Id the >> would work then you can do the work yourself with just a hand drill. >> >> OK it you must use machine threads and they must be #4 size try "rivets" >> these work like pop rivets but leave a hollow thread insert in the hole >> that will take screws. Takes all of 5 seconds to install a thread hole. >> >> Think again about threading aluminum. It is not very strong, it would be >> easy for an end user to strip the #4 threads. Better to use the rivet or >> other steel thread insert.Even native nuts installed with flush >> rivets >> is better >> > > Interestingly enough, for 4-40 hardware, the screws fail before the > aluminum does. The area of the thread engagement is quite a bit larger > than the cross section of the fastener that is not thread. > > For large fasteners, where the thread depth is a smaller fraction of the > fastener diameter, this may not be the case (as anyone who has stripped the > threads on an aluminum cylinder head with a steel sparkplug will know, in a > deep and visceral way). > > > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On Fri, 19 May 2017 12:00:01 -0400, time-nuts-requ...@febo.com wrote: > Re: [time-nuts] Machining some aluminum help! It's much easier to use thread-forming taps in aluminum than thread cutting, and the threads are far stronger. Blind holes are not as large a problem. Lubricate with soft wax, not Tap-Magic. Also, why 4-40 in a 0.25" thick wall? A larger screw will actually be easier and again, stronger. .<https://www.mcmaster.com/#thread-forming-taps/=17p2qoh> .<https://www.mcmaster.com/#lubricant-stick-wax/=17p2rpl> Joe Gwinn ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
These threads where there is not enough information to define the problem can grow forever, because they are based on speculation, not facts. Corby, you have decided what you need based on what you know, but the rest of us need a more general statement of the problem. Unless, of course, that is something you do not choose to reveal. Bill Hawkins ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
> On May 18, 2017, at 8:13 PM, jimlux wrote: > > On 5/18/17 2:36 PM, Chris Albertson wrote: >> It would be easy to re-design the job for cheaper machining.. Do you >> really need to tap the holes? You might use self taping screws. Id the >> would work then you can do the work yourself with just a hand drill. >> >> OK it you must use machine threads and they must be #4 size try "rivets" >> these work like pop rivets but leave a hollow thread insert in the hole >> that will take screws. Takes all of 5 seconds to install a thread hole. >> >> Think again about threading aluminum. It is not very strong, it would be >> easy for an end user to strip the #4 threads. Better to use the rivet or >> other steel thread insert.Even native nuts installed with flush rivets >> is better > > Interestingly enough, for 4-40 hardware, the screws fail before the aluminum > does. The area of the thread engagement is quite a bit larger than the cross > section of the fastener that is not thread. There are a lot of variables involved. Run the screws in and out of the aluminum a number of times and the holes will fail first ….There are other gotchas as well. Bob > > For large fasteners, where the thread depth is a smaller fraction of the > fastener diameter, this may not be the case (as anyone who has stripped the > threads on an aluminum cylinder head with a steel sparkplug will know, in a > deep and visceral way). > > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On 5/18/17 2:36 PM, Chris Albertson wrote: It would be easy to re-design the job for cheaper machining.. Do you really need to tap the holes? You might use self taping screws. Id the would work then you can do the work yourself with just a hand drill. OK it you must use machine threads and they must be #4 size try "rivets" these work like pop rivets but leave a hollow thread insert in the hole that will take screws. Takes all of 5 seconds to install a thread hole. Think again about threading aluminum. It is not very strong, it would be easy for an end user to strip the #4 threads. Better to use the rivet or other steel thread insert.Even native nuts installed with flush rivets is better Interestingly enough, for 4-40 hardware, the screws fail before the aluminum does. The area of the thread engagement is quite a bit larger than the cross section of the fastener that is not thread. For large fasteners, where the thread depth is a smaller fraction of the fastener diameter, this may not be the case (as anyone who has stripped the threads on an aluminum cylinder head with a steel sparkplug will know, in a deep and visceral way). ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Corby, Is it a 'pressure' seal or a 'vacuum' seal? Vacuum should be much easier to achieve. Joe -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of cdel...@juno.com Sent: Thursday, May 18, 2017 3:34 PM To: time-nuts@febo.com Subject: [time-nuts] Machining some aluminum help! Well that generated a lot of advice and thanks for it! I think I might do it myself and go with a 1/2" hole depth and 1/4" threaded depth. I'll get some of that Aluminum Tap magic, some new taps and new drill bits. Good idea about drilling the end plates first and drilling thru to match. Between the end plate and the tube is a gasket that needs to seal pressure and moisture tight. That's why I used 5 per side. Will let you know how it turns out. Cheers, Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
So the goal is not to attach end plates, that is the solution. The real goal is a sealed container that can be re-opened.I suggest a trip to the plumbing supply store.Why not just use screw-on end caps It you need it sealed 4-40 screw are not able to provide any reasonable clamping force. The weak link is the aluminum threads. You need enough force to deform the gasket material and those little screws are not going to do it. If you need a gas tight chamber, look at plumbing parts. They make screw-on end caps with both make and female threads. There is also a system for brazing alumni that work almost as well as celiac welding and you can do it with a propane lumber's torch. They sell the rods at Harbor Freight. Why not post a specification (enclose with x,y,z inside dimension, water/gas tight/ ends on one end,) and ask people for ideas on the lowest cost way to make that using simple tools. There are SO MANY solutions, one is double sided, coper clad PCB material. You can cut it with a wood saw and then solder the panels together to make a box. I find that I can solder brass screws to copy PCB material and make thread posts or studs. On Thu, May 18, 2017 at 4:13 PM, Andy ZL3AG via time-nuts < time-nuts@febo.com> wrote: > > Why are my eyes watering? > > On 19/05/2017, at 5:03 AM, Bob Darlington wrote: > > > I had > > to soak my cavity ring in nitric acid for a month to get the tap out. > > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Andy, Although this is a hydraulic cylinder, this is along the lines of what you described. On Thu, May 18, 2017 at 19:18 Andy ZL3AG via time-nuts wrote: > > > Or go for thicker wall aluminium tube, oversized endplates and long bolts > or threaded rods running the entire length down the outside of the tube so > you're clamping both ends in one operation. No tapping required. Simples! > > > > > On 19/05/2017, at 6:16 AM, Tim Shoppa wrote: > > > I bet you went to 0.25" wall square tubing only because you want to tap > the > > walls for 4-40. Alternative designs can let you use much thinner material > > and a very different flange on the ends, but the costs will likely move > > towards welding/brazing rather than machining. > > > > Tim N3QE > > > > On Thu, May 18, 2017 at 12:54 PM, wrote: > > > >> Hi, > >> > >> I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. > >> > >> I need 20 holes in each end tapped for 4/40 and 1/2" deep. > >> > >> This is for a Rubidium project. > >> > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > -- Ken WA2LBI Sent from one of my mobile devices ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Or go for thicker wall aluminium tube, oversized endplates and long bolts or threaded rods running the entire length down the outside of the tube so you're clamping both ends in one operation. No tapping required. Simples! On 19/05/2017, at 6:16 AM, Tim Shoppa wrote: > I bet you went to 0.25" wall square tubing only because you want to tap the > walls for 4-40. Alternative designs can let you use much thinner material > and a very different flange on the ends, but the costs will likely move > towards welding/brazing rather than machining. > > Tim N3QE > > On Thu, May 18, 2017 at 12:54 PM, wrote: > >> Hi, >> >> I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. >> >> I need 20 holes in each end tapped for 4/40 and 1/2" deep. >> >> This is for a Rubidium project. >> ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Why are my eyes watering? On 19/05/2017, at 5:03 AM, Bob Darlington wrote: > I had > to soak my cavity ring in nitric acid for a month to get the tap out. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
It would be easy to re-design the job for cheaper machining.. Do you really need to tap the holes? You might use self taping screws. Id the would work then you can do the work yourself with just a hand drill. OK it you must use machine threads and they must be #4 size try "rivets" these work like pop rivets but leave a hollow thread insert in the hole that will take screws. Takes all of 5 seconds to install a thread hole. Think again about threading aluminum. It is not very strong, it would be easy for an end user to strip the #4 threads. Better to use the rivet or other steel thread insert.Even native nuts installed with flush rivets is better So try self threading screws first them go to threaded inserts, you could install 100 4-40 inserts in one hour using just hand tools. On Thu, May 18, 2017 at 9:54 AM, wrote: > Hi, > > I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. > > I need 20 holes in each end tapped for 4/40 and 1/2" deep. > > This is for a Rubidium project. > > The local machine shop want's $360.00 > > Anyone have a machining setup that could do the work a bit cheaper? > > If not I'll give it a try myself. > > Please contact me off list. > > Thanks! > > Corby Dawson > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On 5/18/17 1:34 PM, cdel...@juno.com wrote: Well that generated a lot of advice and thanks for it! I think I might do it myself and go with a 1/2" hole depth and 1/4" threaded depth. I'll get some of that Aluminum Tap magic, some new taps and new drill bits. Good idea about drilling the end plates first and drilling thru to match. Between the end plate and the tube is a gasket that needs to seal pressure and moisture tight. That's why I used 5 per side. I would make the end plate "real thick",with a machined groove for the o-ring, and use some sort of latches to hold it in place, rather than "lots 'o screws". Unless you've got a real tight space constraint. How much pressure do you have to hold? That will determine the clamping force needed on your gasket (and potentially, on your fasteners). Do you need the full 4.5x4.5" inside clear space? A 1/4-20 bolt in the corner might be a good way to go. There's also inexpensive surplus vacuum equipment around, as well as run of the mill plumbing. Unless Steel (stainless or not) isn't an option. Will let you know how it turns out. Cheers, Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Content by Scott Typos by Siri > On May 18, 2017, at 4:34 PM, wrote: > > Well that generated a lot of advice and thanks for it! > I think I might do it myself and go with a 1/2" hole depth and 1/4" > threaded depth. > I'll get some of that Aluminum Tap magic, some new taps and new drill > bits. > Good idea about drilling the end plates first and drilling thru to match. > Between the end plate and the tube is a gasket that needs to seal > pressure and moisture tight. That's why I used 5 per side. > > Will let you know how it turns out. > > Cheers, > > Corby > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Yes, generally when something is expensive to manufacture it is because the designer was not thinking about costs. A design with 40 size "tiny" thread holes in just not cost-effective. A redesign could save hours work. On Thu, May 18, 2017 at 11:16 AM, Tim Shoppa wrote: > I'm very dubious that you need a tapped 4-40 hole to be threaded any deeper > than 0.25". If you work with the machinist I'm sure you can come up with > some reasonable spec that does not require a bottoming tap and will save > you a lot of money. > > I bet you went to 0.25" wall square tubing only because you want to tap the > walls for 4-40. Alternative designs can let you use much thinner material > and a very different flange on the ends, but the costs will likely move > towards welding/brazing rather than machining. > > Tim N3QE > > On Thu, May 18, 2017 at 12:54 PM, wrote: > > > Hi, > > > > I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. > > > > I need 20 holes in each end tapped for 4/40 and 1/2" deep. > > > > This is for a Rubidium project. > > > > The local machine shop want's $360.00 > > > > Anyone have a machining setup that could do the work a bit cheaper? > > > > If not I'll give it a try myself. > > > > Please contact me off list. > > > > Thanks! > > > > Corby Dawson > > > > ___ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > > mailman/listinfo/time-nuts > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
If you need pressure moisture tightness you are going to want to have machinist mill tube ends and plates flat if you take off say 075-100 thousands deep and .225 thousanths around edge of plate and have machinist predrill holes in cover plate you will have both a tight seal and drill guide for the tube drilling and tapping. Content by Scott Typos by Siri > On May 18, 2017, at 4:34 PM, wrote: > > Well that generated a lot of advice and thanks for it! > I think I might do it myself and go with a 1/2" hole depth and 1/4" > threaded depth. > I'll get some of that Aluminum Tap magic, some new taps and new drill > bits. > Good idea about drilling the end plates first and drilling thru to match. > Between the end plate and the tube is a gasket that needs to seal > pressure and moisture tight. That's why I used 5 per side. > > Will let you know how it turns out. > > Cheers, > > Corby > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On 18/05/2017 4:34 PM, cdel...@juno.com wrote: I think I might do it myself and go with a 1/2" hole depth and 1/4" threaded depth. Or go back to the shop and get a new quote with them knowing it's not bottom tapping, only 1/4" threaded depth. Michael ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Machining some aluminum help!
Well that generated a lot of advice and thanks for it! I think I might do it myself and go with a 1/2" hole depth and 1/4" threaded depth. I'll get some of that Aluminum Tap magic, some new taps and new drill bits. Good idea about drilling the end plates first and drilling thru to match. Between the end plate and the tube is a gasket that needs to seal pressure and moisture tight. That's why I used 5 per side. Will let you know how it turns out. Cheers, Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On 5/18/17 11:53 AM, jimlux wrote: On 5/18/17 11:16 AM, Tim Shoppa wrote: I'm very dubious that you need a tapped 4-40 hole to be threaded any deeper than 0.25". If you work with the machinist I'm sure you can come up with some reasonable spec that does not require a bottoming tap and will save you a lot of money. Fixing the table formatting ThreadsFastener Engaged Length0.125 in TPI 40 Diameter 0.112 in mean Diam0.0995 in Root Diam0.087 in Engaged area 0.0391 sq in Area 0.00594 sq in Load200 lb Shear stress 5,119 psiStress 33,644 psi Ultimate strength42 ksiultimate74 ksi Shear Strength 24,249 psiproof 55,000 psi Safety factor 4.74Safety factor 1.63 AluminumSteel ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On 5/18/17 11:16 AM, Tim Shoppa wrote: I'm very dubious that you need a tapped 4-40 hole to be threaded any deeper than 0.25". If you work with the machinist I'm sure you can come up with some reasonable spec that does not require a bottoming tap and will save you a lot of money. The rule of thumb is that if you get 3-5 threads fully engaged that's good - so at 40 threads/inch, 5 threads is 1/8" Drill the hole a bit more than 1/4" deep (approx), tap the first 3/16" inch (so you can use a regular old tap), blow the chips out afterwards, use fasteners that are the right length. Is the number of fasteners for mechanical strength, for RF sealing, thermal transfer, or what? You might be able to get by with fewer fasteners if you use a conductive elastomer gasket (or even copper foil tape which deforms when you screw the lid down). 5 fasteners in 5" is spacing them a bit less than an inch apart. Even in Aluminum, your threads are probably stronger than your fastener. Threads Fastener Engaged Length 0.125 in Engaged Length TPI 40 TPI Diameter0.112 in Diameter mean Diam 0.0995 in Root Diam 0.087 mean Diam Engaged area0.0391 sq in Area0.00594 Engaged area Load200 lb Load Shear stress 5,119 psi 33,644 Shear stress Ultimate strength 42 ksi ultimate74 Ultimate strength Shear Strength 24,249 psi proof 55,000 Shear Strength Safety factor 4.74Safety factor1.63 Safety factor AluminumSteel I bet you went to 0.25" wall square tubing only because you want to tap the walls for 4-40. Alternative designs can let you use much thinner material and a very different flange on the ends, but the costs will likely move towards welding/brazing rather than machining. Tim N3QE On Thu, May 18, 2017 at 12:54 PM, wrote: Hi, I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. I need 20 holes in each end tapped for 4/40 and 1/2" deep. This is for a Rubidium project. The local machine shop want's $360.00 Anyone have a machining setup that could do the work a bit cheaper? If not I'll give it a try myself. Please contact me off list. Thanks! Corby Dawson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
I agree, tapping that depth in aluminum is just asking to gall the threads. If you have a decent alloy (6061 7075) you only need 1/8” to hold what ever is save to hold with a #4. If you need more strength then it would be best to use helicoil inserts. Where are you located? There are a number of hacker spaces across the country / globe. If you are in the US, there is also "The Tech Shop”. If you are in the SF Bay Area I would take a look. Link > On May 18, 2017, at 11:16 AM, Tim Shoppa wrote: > > I'm very dubious that you need a tapped 4-40 hole to be threaded any deeper > than 0.25". If you work with the machinist I'm sure you can come up with > some reasonable spec that does not require a bottoming tap and will save > you a lot of money. > > I bet you went to 0.25" wall square tubing only because you want to tap the > walls for 4-40. Alternative designs can let you use much thinner material > and a very different flange on the ends, but the costs will likely move > towards welding/brazing rather than machining. > > Tim N3QE > > On Thu, May 18, 2017 at 12:54 PM, wrote: > >> Hi, >> >> I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. >> >> I need 20 holes in each end tapped for 4/40 and 1/2" deep. >> >> This is for a Rubidium project. >> >> The local machine shop want's $360.00 >> >> Anyone have a machining setup that could do the work a bit cheaper? >> >> If not I'll give it a try myself. >> >> Please contact me off list. >> >> Thanks! >> >> Corby Dawson >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/ >> mailman/listinfo/time-nuts >> and follow the instructions there. >> > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
I'm very dubious that you need a tapped 4-40 hole to be threaded any deeper than 0.25". If you work with the machinist I'm sure you can come up with some reasonable spec that does not require a bottoming tap and will save you a lot of money. I bet you went to 0.25" wall square tubing only because you want to tap the walls for 4-40. Alternative designs can let you use much thinner material and a very different flange on the ends, but the costs will likely move towards welding/brazing rather than machining. Tim N3QE On Thu, May 18, 2017 at 12:54 PM, wrote: > Hi, > > I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. > > I need 20 holes in each end tapped for 4/40 and 1/2" deep. > > This is for a Rubidium project. > > The local machine shop want's $360.00 > > Anyone have a machining setup that could do the work a bit cheaper? > > If not I'll give it a try myself. > > Please contact me off list. > > Thanks! > > Corby Dawson > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
People's (mis)perception of machine shop costs always amazes me. All too often they equate the fact that they could do it themselves (inaccurately) on an old drill press and then hand tap with what a real shop will do - all while that real shop has a $100k - $500k investment in a single machine. Yes it can be done cheaper, but not profitably. Its why people end up with 25k pounds of machinery in their garage (nothing wrong with that). Its really no different than what you would expect if you took your rubidium standard into a small, profitable RF shop and asked them to characterize it - they would charge you going rate. Which is why many of us end up with 1000's of sounds of test equipment in the basement or back bedroom - in addition to the machine shop in the garage. Brent On Thu, May 18, 2017 at 1:27 PM, Todd Caldwell wrote: > Tap Magic for Aluminum will be your best friend for this operation. > > I've been using it on some extrusion for a 3D printer project. It makes an > amazing amount of difference. > > Good luck with you project. > > Todd > > > > On 05/18/17 12:18, Pete Lancashire wrote: > >> Price sounds reasonable to me. >> >> Tapping 40 each 4-40's that deep in to a closed hole is the killer. If I >> still had my old Bridgeport J and was NC'ed Your looking at say 1 hour to >> program, 10 minutes to mount in a vice and get aligned, drill 40 each #44 >> or #43 holes would be easy, but then slow things down, cross fingers and >> start tapping. >> >> Doing it by hand, at 1/2 deep those holes better be close to "perfectly" >> aligned. >> >> >> On Thu, May 18, 2017 at 9:54 AM, wrote: >> >> Hi, >>> >>> I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. >>> >>> I need 20 holes in each end tapped for 4/40 and 1/2" deep. >>> >>> This is for a Rubidium project. >>> >>> The local machine shop want's $360.00 >>> >>> Anyone have a machining setup that could do the work a bit cheaper? >>> >>> If not I'll give it a try myself. >>> >>> Please contact me off list. >>> >>> Thanks! >>> >>> Corby Dawson >>> >>> ___ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/ >>> mailman/listinfo/time-nuts >>> and follow the instructions there. >>> >>> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/m >> ailman/listinfo/time-nuts >> and follow the instructions there. >> >> > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Tap Magic for Aluminum will be your best friend for this operation. I've been using it on some extrusion for a 3D printer project. It makes an amazing amount of difference. Good luck with you project. Todd On 05/18/17 12:18, Pete Lancashire wrote: Price sounds reasonable to me. Tapping 40 each 4-40's that deep in to a closed hole is the killer. If I still had my old Bridgeport J and was NC'ed Your looking at say 1 hour to program, 10 minutes to mount in a vice and get aligned, drill 40 each #44 or #43 holes would be easy, but then slow things down, cross fingers and start tapping. Doing it by hand, at 1/2 deep those holes better be close to "perfectly" aligned. On Thu, May 18, 2017 at 9:54 AM, wrote: Hi, I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. I need 20 holes in each end tapped for 4/40 and 1/2" deep. This is for a Rubidium project. The local machine shop want's $360.00 Anyone have a machining setup that could do the work a bit cheaper? If not I'll give it a try myself. Please contact me off list. Thanks! Corby Dawson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Price sounds reasonable to me. Tapping 40 each 4-40's that deep in to a closed hole is the killer. If I still had my old Bridgeport J and was NC'ed Your looking at say 1 hour to program, 10 minutes to mount in a vice and get aligned, drill 40 each #44 or #43 holes would be easy, but then slow things down, cross fingers and start tapping. Doing it by hand, at 1/2 deep those holes better be close to "perfectly" aligned. On Thu, May 18, 2017 at 9:54 AM, wrote: > Hi, > > I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. > > I need 20 holes in each end tapped for 4/40 and 1/2" deep. > > This is for a Rubidium project. > > The local machine shop want's $360.00 > > Anyone have a machining setup that could do the work a bit cheaper? > > If not I'll give it a try myself. > > Please contact me off list. > > Thanks! > > Corby Dawson > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On 5/18/17 10:03 AM, Bob Darlington wrote: Ask them what they'd do it for without the tapping. Normally I'd do something like this for free but 40 tapped 4-40 holes in heavy wall aluminum is a pain. It would be a miracle if I didn't break the tap off at least once. Very much so.. 40 tapped holes is a lot of holes Last time was for a resonant cavity amp (23cm band) and I had to soak my cavity ring in nitric acid for a month to get the tap out. At least it's not steel. Or copper(!) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
This is fairly easy to do on a vertical mill, but it can be done using a drill press. I would machine and drill the end plates first. Then I would use hot-glue or double-sided tape to attach one of the end plates to the tube ends and use the end plate as a drilling guide to drill and tap the holes in the tube. The critical aspect of drilling the tube holes is that the end of the tube that is being drilled has to be absolutely perpendicular to the drill bit. The drill press can also be used to tap the holes - with the drill press power off, install the tap and hand turn the spindle while using the lever arm to gently follow the tap in as it cuts. Since it is aluminum, hand-tapping the holes without using the drill press should be fairly easy also. DaveD On 5/18/2017 10:54 AM, cdel...@juno.com wrote: Hi, I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. I need 20 holes in each end tapped for 4/40 and 1/2" deep. This is for a Rubidium project. The local machine shop want's $360.00 Anyone have a machining setup that could do the work a bit cheaper? If not I'll give it a try myself. Please contact me off list. Thanks! Corby Dawson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
Ask them what they'd do it for without the tapping. Normally I'd do something like this for free but 40 tapped 4-40 holes in heavy wall aluminum is a pain. It would be a miracle if I didn't break the tap off at least once. Last time was for a resonant cavity amp (23cm band) and I had to soak my cavity ring in nitric acid for a month to get the tap out. At least it's not steel. -Bob On Thu, May 18, 2017 at 10:54 AM, wrote: > Hi, > > I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. > > I need 20 holes in each end tapped for 4/40 and 1/2" deep. > > This is for a Rubidium project. > > The local machine shop want's $360.00 > > Anyone have a machining setup that could do the work a bit cheaper? > > If not I'll give it a try myself. > > Please contact me off list. > > Thanks! > > Corby Dawson > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Machining some aluminum help!
On 5/18/17 9:54 AM, cdel...@juno.com wrote: Hi, I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. I need 20 holes in each end tapped for 4/40 and 1/2" deep. So you're putting 5 holes in each side? in the ends? (i.e. the long axis of the screw is within the wall? That's a fairly tricky operation, especially if the tube is standard extruded tube, because the sides might not be perfectly flat or at right angles. You're drilling a 0.112 hole in a 0.25" wall, so you've got some clearance, but I assume you've got a matching cover plate you want to attach? How critical is the spacing of the holes? A good drill press (or vertical mill), and a really good clamping setup, and "match drill" the cover plate and the tube at the same time. This is for a Rubidium project. The local machine shop want's $360.00 Anyone have a machining setup that could do the work a bit cheaper? If not I'll give it a try myself. Please contact me off list. Thanks! Corby Dawson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Machining some aluminum help!
Hi, I have a square aluminum tube 5" X 5" with a .25" wall it's 8 1/2" long. I need 20 holes in each end tapped for 4/40 and 1/2" deep. This is for a Rubidium project. The local machine shop want's $360.00 Anyone have a machining setup that could do the work a bit cheaper? If not I'll give it a try myself. Please contact me off list. Thanks! Corby Dawson ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.