Re: [Emc-users] New problem, how best to solve?

[Gene Heskett]

On Monday 18 February 2019 20:50:10 Ken Strauss wrote:

> > -Original Message-
> > From: Gene Heskett [mailto:ghesk...@shentel.net]
> > Sent: Monday, February 18, 2019 7:20 PM
> > To: emc-users@lists.sourceforge.net
> > Subject: Re: [Emc-users] New problem, how best to solve?
> >
> > On Monday 18 February 2019 16:56:38 jrmitchellj wrote:
> > > Hey Gene, If you were so inclined to make your own touch probe,
> > > there is an article in the winter 2011 edition of Digital
> > > Machinist that describes a construction project.
> > > If interested, send your email address to me, and I will send more
> > > information.
> > >
> > > --J. Ray Mitchell Jr.
> > > jrmitche...@gmail.com
> >
> > Its the from line above, if it survives the list
> > else try ghesk...@shentel.net.  I'd be interested in anything thats
> > half the size of a renishaw.
> >
> > Thanks J. Ray.
>
> I haven't been following this discussion closely. What are your size
> restrictions? I'd have to go to the shop to measure exactly but a
> Renishaw MP3 is about 3.25 inch in diameter and 2.5 inch in Z-height.
>
Generally, thats to big. And I'd have doubts I could put it in an er-11 
collet. The el-cheepo I just bought has a 1/4" top stud, 2.1" diameter, 
and with the default probe, a hair over 4" tall.  And that will eat much 
of the z height of this machine. I should know for sure by this time 
next week as it ships from stateside. Maybe the dual mister will be here 
by then, but its promised the 27th soonest. The 2nd air valve? Middle of 
March...
>
>
>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page <http://geneslinuxbox.net:6309/gene>



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Re: [Emc-users] New problem, how best to solve?

[Ken Strauss]

> -Original Message-
> From: Gene Heskett [mailto:ghesk...@shentel.net]
> Sent: Monday, February 18, 2019 7:20 PM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] New problem, how best to solve?
>
> On Monday 18 February 2019 16:56:38 jrmitchellj wrote:
>
> > Hey Gene, If you were so inclined to make your own touch probe, there
> > is an article in the winter 2011 edition of Digital Machinist that
> > describes a construction project.
> > If interested, send your email address to me, and I will send more
> > information.
> >
> > --J. Ray Mitchell Jr.
> > jrmitche...@gmail.com
> >
> Its the from line above, if it survives the list
> else try ghesk...@shentel.net.  I'd be interested in anything thats half
> the size of a renishaw.
>
> Thanks J. Ray.

I haven't been following this discussion closely. What are your size
restrictions? I'd have to go to the shop to measure exactly but a Renishaw
MP3 is about 3.25 inch in diameter and 2.5 inch in Z-height.




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Re: [Emc-users] New problem, how best to solve?

[Gene Heskett]

On Monday 18 February 2019 16:56:38 jrmitchellj wrote:

> Hey Gene, If you were so inclined to make your own touch probe, there
> is an article in the winter 2011 edition of Digital Machinist that
> describes a construction project.
> If interested, send your email address to me, and I will send more
> information.
>
> --J. Ray Mitchell Jr.
> jrmitche...@gmail.com
>
Its the from line above, if it survives the list
else try ghesk...@shentel.net.  I'd be interested in anything thats half 
the size of a renishaw.

Thanks J. Ray.
>
> "No problem can be solved from the same level of consciousness that
> created it"Albert Einstein
>
> On Mon, Feb 18, 2019 at 9:57 AM Gene Heskett  
wrote:
> > On Monday 18 February 2019 05:53:31 Gene Heskett wrote:
> > > On Monday 18 February 2019 02:31:46 jrmitchellj wrote:
> > > > Perhaps victims of the Trump tariffs!
> > > >
> > > > --J. Ray Mitchell Jr.
> > > > jrmitche...@gmail.com
> >
> > I've not seen anything thats blaming that BS yet...
> >
> >  But I did note that one opto based proximity detector on ebay just
> > now, no real specs listed but $0.99 copy. But shipping from the
> > Russian Federation was $30, and delivery estimates were 90 days. If
> > you needed 10,000 next year, maybe, but 10 yesterday?
> >
> > Most of the proximity stuff is designed to work with ferrous,
> > worthless for locating an alu workpiece. But it sure seems to me
> > that the market for a $5 sensor, accurate to .001" or better is wide
> > open, and whoever comes up with such a device will own the market.
> > It exists of course, called a switch, but would have to be designed
> > for that specific job. Its not something that you could just turn a
> > G38.2 loose on without some preliminary fumbling to find the target.
> >  Looking for the edge of an anodized alu panel 70 thou thick is not
> > an easy job w/o some sort of machine vision. Electrical contact
> > detection in the presence of the anodic coating only becomes
> > practical when you've a kilovolt to puncture that coating, or enough
> > mechanical force to damage it and I've neither. That leaves
> > something resembling a Renishaw. Or machining a pallet locked to the
> > table for alignment for every part you make, which except for pcb's
> > you are going to mechanically etch 100's of, has proven to be a huge
> > waste of time. IMO anyway. This machine with its target being
> > engraving, may be fast enough that it won't starve the operator.
> >
> > Up till now I've always been so limited in feed speeds by the
> > available spindle rpms that making a pcb resembled watching grass
> > grow in the time of a drought. With 10x the revs, I ought to be able
> > to carve a pcb at 30 ipm. There will no doubt be other limits found
> > long before getting to a 30 ipm average speed. Because the moving
> > parts are lighter than a conventional mills table, I expect accel's
> > can be pushed some. But thats something I haven't yet explored,
> > waiting till its moving on all-mesa i/o, so far its still on a
> > parport and moving 10x faster than the older HF, with the same
> > driver kit, stolen from it.  Same BoB too.
> >
> > And I haven't seen an obit for Murphy yet. He must be immortal... :)
> >
> > Cheers, Gene Heskett
> > --
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author)
> > Genes Web page 
> >
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
> ___
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> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 



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Re: [Emc-users] New problem, how best to solve?

[jrmitchellj]

Hey Gene, If you were so inclined to make your own touch probe, there is an
article in the winter 2011 edition of Digital Machinist that describes a
construction project.
If interested, send your email address to me, and I will send more
information.

--J. Ray Mitchell Jr.
jrmitche...@gmail.com



"No problem can be solved from the same level of consciousness that created
it"Albert Einstein


On Mon, Feb 18, 2019 at 9:57 AM Gene Heskett  wrote:

> On Monday 18 February 2019 05:53:31 Gene Heskett wrote:
>
> > On Monday 18 February 2019 02:31:46 jrmitchellj wrote:
> > > Perhaps victims of the Trump tariffs!
> > >
> > > --J. Ray Mitchell Jr.
> > > jrmitche...@gmail.com
>
> I've not seen anything thats blaming that BS yet...
>
>  But I did note that one opto based proximity detector on ebay just now,
> no real specs listed but $0.99 copy. But shipping from the Russian
> Federation was $30, and delivery estimates were 90 days. If you needed
> 10,000 next year, maybe, but 10 yesterday?
>
> Most of the proximity stuff is designed to work with ferrous, worthless
> for locating an alu workpiece. But it sure seems to me that the market
> for a $5 sensor, accurate to .001" or better is wide open, and whoever
> comes up with such a device will own the market. It exists of course,
> called a switch, but would have to be designed for that specific job.
> Its not something that you could just turn a G38.2 loose on without some
> preliminary fumbling to find the target.  Looking for the edge of an
> anodized alu panel 70 thou thick is not an easy job w/o some sort of
> machine vision. Electrical contact detection in the presence of the
> anodic coating only becomes practical when you've a kilovolt to puncture
> that coating, or enough mechanical force to damage it and I've neither.
> That leaves something resembling a Renishaw. Or machining a pallet
> locked to the table for alignment for every part you make, which except
> for pcb's you are going to mechanically etch 100's of, has proven to be
> a huge waste of time. IMO anyway. This machine with its target being
> engraving, may be fast enough that it won't starve the operator.
>
> Up till now I've always been so limited in feed speeds by the available
> spindle rpms that making a pcb resembled watching grass grow in the time
> of a drought. With 10x the revs, I ought to be able to carve a pcb at 30
> ipm. There will no doubt be other limits found long before getting to a
> 30 ipm average speed. Because the moving parts are lighter than a
> conventional mills table, I expect accel's can be pushed some. But thats
> something I haven't yet explored, waiting till its moving on all-mesa
> i/o, so far its still on a parport and moving 10x faster than the older
> HF, with the same driver kit, stolen from it.  Same BoB too.
>
> And I haven't seen an obit for Murphy yet. He must be immortal... :)
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page 
>
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] New problem, how best to solve?

[Gene Heskett]

On Monday 18 February 2019 05:53:31 Gene Heskett wrote:

> On Monday 18 February 2019 02:31:46 jrmitchellj wrote:
> > Perhaps victims of the Trump tariffs!
> >
> > --J. Ray Mitchell Jr.
> > jrmitche...@gmail.com

I've not seen anything thats blaming that BS yet...

 But I did note that one opto based proximity detector on ebay just now, 
no real specs listed but $0.99 copy. But shipping from the Russian 
Federation was $30, and delivery estimates were 90 days. If you needed 
10,000 next year, maybe, but 10 yesterday?

Most of the proximity stuff is designed to work with ferrous, worthless 
for locating an alu workpiece. But it sure seems to me that the market 
for a $5 sensor, accurate to .001" or better is wide open, and whoever 
comes up with such a device will own the market. It exists of course, 
called a switch, but would have to be designed for that specific job. 
Its not something that you could just turn a G38.2 loose on without some 
preliminary fumbling to find the target.  Looking for the edge of an 
anodized alu panel 70 thou thick is not an easy job w/o some sort of 
machine vision. Electrical contact detection in the presence of the 
anodic coating only becomes practical when you've a kilovolt to puncture 
that coating, or enough mechanical force to damage it and I've neither. 
That leaves something resembling a Renishaw. Or machining a pallet 
locked to the table for alignment for every part you make, which except 
for pcb's you are going to mechanically etch 100's of, has proven to be 
a huge waste of time. IMO anyway. This machine with its target being 
engraving, may be fast enough that it won't starve the operator.

Up till now I've always been so limited in feed speeds by the available 
spindle rpms that making a pcb resembled watching grass grow in the time 
of a drought. With 10x the revs, I ought to be able to carve a pcb at 30 
ipm. There will no doubt be other limits found long before getting to a 
30 ipm average speed. Because the moving parts are lighter than a 
conventional mills table, I expect accel's can be pushed some. But thats 
something I haven't yet explored, waiting till its moving on all-mesa 
i/o, so far its still on a parport and moving 10x faster than the older 
HF, with the same driver kit, stolen from it.  Same BoB too.

And I haven't seen an obit for Murphy yet. He must be immortal... :)

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 



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Re: [Emc-users] New problem, how best to solve?

[Gene Heskett]

On Monday 18 February 2019 02:31:46 jrmitchellj wrote:

> Perhaps victims of the Trump tariffs!
>
> --J. Ray Mitchell Jr.
> jrmitche...@gmail.com
>
>
>
> "No problem can be solved from the same level of consciousness that
> created it"Albert Einstein
>
> On Sun, Feb 17, 2019 at 4:00 PM Gene Heskett  
wrote:
> > On Saturday 16 February 2019 20:01:38 Gene Heskett wrote:
> > > On Saturday 16 February 2019 14:28:33 Chris Albertson wrote:
> > > > Thinking about this as an electrical engineer,  I'd say don't
> > > > use DC. DC current is as you say blocked by paint and oil films.
> > > >Use AC. I think a low radio frequency.   Then the DC
> > > > insulators would act like capacitors and pass AC. even while
> > > > blocking DC.  To detect contact use an AC voltage sensor,
> > > > typically a diode and small capacitor.
> > >
> > > The disadvantage there is the rc charge time. This means among
> > > other things a relatively leasure velocity to the first trip, and
> > > a much slower 2nd approach, where as in using the dc circuit, one
> > > usually uses a rotating with the spindle probe so even  if it has
> > > some runnout, the contact surface is recorded an by the first
> > > contact discharging a .1 ufcapacitor, which takes long enough to
> > > recharge that the contacts logic zero, is captured and reported to
> > > LCNC instantly even if by the time the servo thread actually reads
> > > it, the contact has been lost again for .9 milliseconds. The rf
> > > circuit, cannot possibly respond in that time frame unless the
> > > closing velocities are also very slow. The DC method is inherently
> > > the faster method, but does require a very low ohmage connection
> > > in order to fully discharge the cap  on a 10 microsecond contact. 
> > > And we definitely DON'T have a low resistance circuit on this
> > > machine.
> > >
> > > I have one of this old tony's contacts about 75% made, but out of
> > > a brass tube instead of a steel probe and I'll take the machine
> > > out of it by grounding the workpiece, and wiring the tube straight
> > > to the probe input, using the same old cap for storage. The brass
> > > is long enough it can hit and be bent 1/4" without damage as it
> > > will just spring back.
> > >
> > > But its been a long day today.  I'll figure out something thats
> > > hopefully repeatable.
> >
> > Got that done, almost worked when using brass against the edge of
> > this alu panel, so I thought I'd get fancy, and found a steel sewing
> > pit with the rounded backend sewing pin and soldered it into the tip
> > of the tube. Disaster, I can see it sliding along on jerks as I run
> > it back and forth touching the edge of the alu, but the only place
> > its making actual contact is where the brushed finish is damaged,
> > anyplace else needs a 10lb push with my finger to break thru the
> > aloxide and actually make a contact. Would probably work with most
> > anything metallic except the alu. To do this would need a 1kv
> > supply, limited to 1 microamp so as not to eat up the probe too fast
> > and measure the voltage electrostaticly.
> >
> > Last week there were at least a dozen guys selling imitation
> > Reneshaws for 69$/copy.  But I'll be darned if I can find one on
> > fleabay today.

Finally found one and bought it. They sure are BIG though, 2.1" in 
diameter and 4+" long. And Z motion is certainly limited with that 
installed!  Bought a t.l.o. setter and a big bag of teeny homing 
switches. This thing has blocks of solid cambric for crash stops, looks 
like a 2.5mm thick switch glued in there ought to make a serviceable 
homing switch. Now we sit and wait, bored out of my skull till stuff 
gets here. Sigh.

> > > And I've got to figure what to do Monday as my lady adds another
> > > year to her journey on this ball of rock and water, making it to
> > > her 79nth.
> > >
> > > Something she'll appreciate without any physical effort. With
> > > copd, there's not much of that left.  Sigh...
> > >
> > > That said, I think the DC method can be made to work with a
> > > separately wired probe, with both the ground on the workpiece and
> > > the hot on the probe wired independently from the machine. Run the
> > > probe cable as a shielded wire in the cable chain.  At least this
> > > chain can be opened to add more wire, something none of the other
> > > cable chain I've bought can do.  Nice!
> > >
> > > > I don't know if this is done commercially but the AC method
> > > > should in theory by MUCH more reliable.You can even use very
> > > > long cables if you use strong filters tuned to the frequency.   
> > > >  Notice how well the current passes from an AM radio station to
> > > > your radio even over a miles-long air gap.
> > > >
> > > > My guess is that a 100 KHz signal would go right through paint.
> > > >
> > > > On Sat, Feb 16, 2019 at 9:46 AM Gene Heskett
> > > > 
> > >
> > > wrote:
> > > > > Greetings all;
> > > > >
> > > > > I've just found that because everything it painted before
> > > 

Re: [Emc-users] New problem, how best to solve?

[jrmitchellj]

Perhaps victims of the Trump tariffs!

--J. Ray Mitchell Jr.
jrmitche...@gmail.com



"No problem can be solved from the same level of consciousness that created
it"Albert Einstein


On Sun, Feb 17, 2019 at 4:00 PM Gene Heskett  wrote:

> On Saturday 16 February 2019 20:01:38 Gene Heskett wrote:
>
> > On Saturday 16 February 2019 14:28:33 Chris Albertson wrote:
> > > Thinking about this as an electrical engineer,  I'd say don't use
> > > DC. DC current is as you say blocked by paint and oil films.Use
> > > AC. I think a low radio frequency.   Then the DC insulators would
> > > act like capacitors and pass AC. even while blocking DC.  To detect
> > > contact use an AC voltage sensor, typically a diode and small
> > > capacitor.
> >
> > The disadvantage there is the rc charge time. This means among other
> > things a relatively leasure velocity to the first trip, and a much
> > slower 2nd approach, where as in using the dc circuit, one usually
> > uses a rotating with the spindle probe so even  if it has some
> > runnout, the contact surface is recorded an by the first contact
> > discharging a .1 ufcapacitor, which takes long enough to recharge that
> > the contacts logic zero, is captured and reported to LCNC instantly
> > even if by the time the servo thread actually reads it, the contact
> > has been lost again for .9 milliseconds. The rf circuit, cannot
> > possibly respond in that time frame unless the closing velocities are
> > also very slow. The DC method is inherently the faster method, but
> > does require a very low ohmage connection in order to fully discharge
> > the cap  on a 10 microsecond contact.  And we definitely DON'T have a
> > low resistance circuit on this machine.
> >
> > I have one of this old tony's contacts about 75% made, but out of a
> > brass tube instead of a steel probe and I'll take the machine out of
> > it by grounding the workpiece, and wiring the tube straight to the
> > probe input, using the same old cap for storage. The brass is long
> > enough it can hit and be bent 1/4" without damage as it will just
> > spring back.
> >
> > But its been a long day today.  I'll figure out something thats
> > hopefully repeatable.
> >
> Got that done, almost worked when using brass against the edge of this
> alu panel, so I thought I'd get fancy, and found a steel sewing pit with
> the rounded backend sewing pin and soldered it into the tip of the tube.
> Disaster, I can see it sliding along on jerks as I run it back and forth
> touching the edge of the alu, but the only place its making actual
> contact is where the brushed finish is damaged, anyplace else needs a
> 10lb push with my finger to break thru the aloxide and actually make a
> contact. Would probably work with most anything metallic except the alu.
> To do this would need a 1kv supply, limited to 1 microamp so as not to
> eat up the probe too fast and measure the voltage electrostaticly.
>
> Last week there were at least a dozen guys selling imitation Reneshaws
> for 69$/copy.  But I'll be darned if I can find one on fleabay today.
>
>
>
>
>
>
>
>
>
>
> > And I've got to figure what to do Monday as my lady adds another year
> > to her journey on this ball of rock and water, making it to her 79nth.
> >
> > Something she'll appreciate without any physical effort. With copd,
> > there's not much of that left.  Sigh...
> >
> > That said, I think the DC method can be made to work with a separately
> > wired probe, with both the ground on the workpiece and the hot on the
> > probe wired independently from the machine. Run the probe cable as a
> > shielded wire in the cable chain.  At least this chain can be opened
> > to add more wire, something none of the other cable chain I've bought
> > can do.  Nice!
> >
> > > I don't know if this is done commercially but the AC method should
> > > in theory by MUCH more reliable.You can even use very long
> > > cables if you use strong filters tuned to the frequency. Notice
> > > how well the current passes from an AM radio station to your radio
> > > even over a miles-long air gap.
> > >
> > > My guess is that a 100 KHz signal would go right through paint.
> > >
> > > On Sat, Feb 16, 2019 at 9:46 AM Gene Heskett 
> >
> > wrote:
> > > > Greetings all;
> > > >
> > > > I've just found that because everything it painted before
> > > > assembly, apparently including the inside of the spindle motor
> > > > mount, that a ground to the bed frame can be anywhere up to 2 or
> > > > more thousand ohms to almost anything else on the 6040, and
> > > > apparently even includes the spindle bearings as part of the first
> > > > 50 or so ohms.
> > > >
> > > > The net result is that using the workpiece as one contact, the the
> > > > tool in the spindle as the other for the alignment function is
> > > > fraught with enough variables I could break a tool against the
> > > > edge of the workpiece, even damaging the workpiece, before a
> > > > contact is detected. Since there isn't Z room enough 

Re: [Emc-users] New problem, how best to solve?

[Gene Heskett]

On Saturday 16 February 2019 20:01:38 Gene Heskett wrote:

> On Saturday 16 February 2019 14:28:33 Chris Albertson wrote:
> > Thinking about this as an electrical engineer,  I'd say don't use
> > DC. DC current is as you say blocked by paint and oil films.Use 
> > AC. I think a low radio frequency.   Then the DC insulators would
> > act like capacitors and pass AC. even while blocking DC.  To detect
> > contact use an AC voltage sensor, typically a diode and small
> > capacitor.
>
> The disadvantage there is the rc charge time. This means among other
> things a relatively leasure velocity to the first trip, and a much
> slower 2nd approach, where as in using the dc circuit, one usually
> uses a rotating with the spindle probe so even  if it has some
> runnout, the contact surface is recorded an by the first contact
> discharging a .1 ufcapacitor, which takes long enough to recharge that
> the contacts logic zero, is captured and reported to LCNC instantly
> even if by the time the servo thread actually reads it, the contact
> has been lost again for .9 milliseconds. The rf circuit, cannot
> possibly respond in that time frame unless the closing velocities are
> also very slow. The DC method is inherently the faster method, but
> does require a very low ohmage connection in order to fully discharge
> the cap  on a 10 microsecond contact.  And we definitely DON'T have a
> low resistance circuit on this machine.
>
> I have one of this old tony's contacts about 75% made, but out of a
> brass tube instead of a steel probe and I'll take the machine out of
> it by grounding the workpiece, and wiring the tube straight to the
> probe input, using the same old cap for storage. The brass is long
> enough it can hit and be bent 1/4" without damage as it will just
> spring back.
>
> But its been a long day today.  I'll figure out something thats
> hopefully repeatable.
>
Got that done, almost worked when using brass against the edge of this 
alu panel, so I thought I'd get fancy, and found a steel sewing pit with 
the rounded backend sewing pin and soldered it into the tip of the tube. 
Disaster, I can see it sliding along on jerks as I run it back and forth 
touching the edge of the alu, but the only place its making actual 
contact is where the brushed finish is damaged, anyplace else needs a 
10lb push with my finger to break thru the aloxide and actually make a 
contact. Would probably work with most anything metallic except the alu.
To do this would need a 1kv supply, limited to 1 microamp so as not to 
eat up the probe too fast and measure the voltage electrostaticly.  

Last week there were at least a dozen guys selling imitation Reneshaws 
for 69$/copy.  But I'll be darned if I can find one on fleabay today.   








  
> And I've got to figure what to do Monday as my lady adds another year
> to her journey on this ball of rock and water, making it to her 79nth.
>
> Something she'll appreciate without any physical effort. With copd,
> there's not much of that left.  Sigh...
>
> That said, I think the DC method can be made to work with a separately
> wired probe, with both the ground on the workpiece and the hot on the
> probe wired independently from the machine. Run the probe cable as a
> shielded wire in the cable chain.  At least this chain can be opened
> to add more wire, something none of the other cable chain I've bought
> can do.  Nice!
>
> > I don't know if this is done commercially but the AC method should
> > in theory by MUCH more reliable.You can even use very long
> > cables if you use strong filters tuned to the frequency. Notice
> > how well the current passes from an AM radio station to your radio
> > even over a miles-long air gap.
> >
> > My guess is that a 100 KHz signal would go right through paint.
> >
> > On Sat, Feb 16, 2019 at 9:46 AM Gene Heskett 
>
> wrote:
> > > Greetings all;
> > >
> > > I've just found that because everything it painted before
> > > assembly, apparently including the inside of the spindle motor
> > > mount, that a ground to the bed frame can be anywhere up to 2 or
> > > more thousand ohms to almost anything else on the 6040, and
> > > apparently even includes the spindle bearings as part of the first
> > > 50 or so ohms.
> > >
> > > The net result is that 

Re: [Emc-users] New problem, how best to solve?

[Gene Heskett]

On Sunday 17 February 2019 02:28:07 Roland Jollivet wrote:

> If this is for a touch probe or something of the sort, you only need
> contact when the RPM < 500?
>
Getting <500 out of this vfd presents a couple problems, 1st being the 
resolution of its pot, its horrible and linear. I don't know the ohmage 
of the pot, but if its around 10k, I may have some 10 turn highly 
precise pots. But mounted where this one is might project out into 
thespace the vfd occupies.

2. asking a 3 phase motor to turn that slow, will, if the vfd is tuned to 
get and decent low speed torque, it will also burn up the motor by 
running it at only 5 hz or so. Tuneing a vfd to the task at hand needs a 
degree from Hogwarts as this vfd maker is Chinese, and speaks no 
Engrish.

> So, have a setup that if RPM is higher than 500, then a little
> solenoid that tensions the braid (not spring, as you say) is released
> so there is no tension on it.
> You want a copper braid around the spindle..

I've not progressed to the point where I can extract the rpms from it, 
yet. If I can the lcnc can handle the solenoid. But I've other stuff on 
my plate as I bring this new machine to a usable state. Doing that would 
be cake frosting. First you need a cake etc. I've gien some thought to 
sensing the wrench flats with a pair of ATS-667's and cobbling it a tach 
display from that. But that sort of stuff is months down the log yet.

Thanks for the input Roland.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 



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[Emc-users] New problem, how best to solve?

[Roland Jollivet]

If this is for a touch probe or something of the sort, you only need
contact when the RPM < 500?

So, have a setup that if RPM is higher than 500, then a little solenoid
that tensions the braid (not spring, as you say) is released so there is no
tension on it.
You want a copper braid around the spindle..


On Sun, 17 Feb 2019 at 09:01, Gene Heskett  wrote:

> On Saturday 16 February 2019 22:46:26 Roland Jollivet wrote:
>
> > > > Any other ideas out there? Hopefully something that doesn't
> > > > involve changing tools to use.
> >
> > I don't know what your spindle looks like, but to make an electrical
> > connection to it, you could use a piece of earth shield. The woven,
> > braid type that you find on better quality cables. These are usually
> > plated copper, or plain copper. Soft and resilient.
> >
> > Find a place anywhere on the spindle to wrap it a 1/2 turn, pinch the
> > two ends together, and pulled taut with a very light spring. I think
> > it's easier, and better than trying to use brushes.
> > Make a handful while you're at it to replace every 2 years.
>
> I've done that on the G0704 as its spindle has a reasonable speed, 3k
> tops, and I can dial up 50 rpm in either direction.
>
> This is a 24k rpm spindle, with an er11 chuck. So its exposed surface is
> around 9/16" in diameter. At full song, I expect it to burn up the
> spring where the coils touch the spinning chuck. Something along the
> lines of a dremel tool's brush would live much longer. And as it would
> have to run  on the narrow area above the wrench flats, plus the tir is
> at least half a thou, it more than likely would need some sort of a
> retractor simply because the brush is not able to track the tir and
> maintain good contact at the higher speeds. Haveing rebrushed a dremel
> or 5 over the last 65 years, you are wasting your time if you do not
> also turn the commutator to reduce its tir. All you get is excessive
> arcing because the brush is bouncing away from the worn commutator.
>
> That retraction is not a problem other than arranging to do it as the
> spindle revs increase. Where I've used a tool as the contact, I
> generally spin the tool backwards so as not to put cut marks on the work
> when doing the measurements. Retracting the brush when the revs go above
> 5k or so is something I haven't given any thought to. Its also possible
> that some sort of a weak metallic brush could be laid against the
> spindle, but what happens to it when your are spinning it backwards at
> what would be creep speeds.  Given the full song rpms, I don't see a
> long life for any direct contact solution other than the carbon brush.
>
> As soon as I get the new interface I am building up and running so that I
> have enough i/o, I'll put in home switches just so I can set sw limits
> just short of crashes, then I'll probably write me a corner of the
> workpiece finder using the new probe I installed today, making heavy use
> of g38.2, (not applicable to wood projects though, darnit). Then
> determine those x-y offsets and incorporate them into my code.  The
> natural progression then is to write a skeleton that incorporates all
> that, making the next project after this one even easier.
>
> Basicly, I'm lazy, write it once, run it as many times as I need. ;-)
>
> Cheers Roland, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page 
>
>
>
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>

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Re: [Emc-users] New problem, how best to solve?

[Gene Heskett]

On Saturday 16 February 2019 22:46:26 Roland Jollivet wrote:

> > > Any other ideas out there? Hopefully something that doesn't
> > > involve changing tools to use.
>
> I don't know what your spindle looks like, but to make an electrical
> connection to it, you could use a piece of earth shield. The woven,
> braid type that you find on better quality cables. These are usually
> plated copper, or plain copper. Soft and resilient.
>
> Find a place anywhere on the spindle to wrap it a 1/2 turn, pinch the
> two ends together, and pulled taut with a very light spring. I think
> it's easier, and better than trying to use brushes.
> Make a handful while you're at it to replace every 2 years.

I've done that on the G0704 as its spindle has a reasonable speed, 3k 
tops, and I can dial up 50 rpm in either direction.

This is a 24k rpm spindle, with an er11 chuck. So its exposed surface is 
around 9/16" in diameter. At full song, I expect it to burn up the 
spring where the coils touch the spinning chuck. Something along the 
lines of a dremel tool's brush would live much longer. And as it would 
have to run  on the narrow area above the wrench flats, plus the tir is 
at least half a thou, it more than likely would need some sort of a 
retractor simply because the brush is not able to track the tir and 
maintain good contact at the higher speeds. Haveing rebrushed a dremel 
or 5 over the last 65 years, you are wasting your time if you do not 
also turn the commutator to reduce its tir. All you get is excessive 
arcing because the brush is bouncing away from the worn commutator.

That retraction is not a problem other than arranging to do it as the 
spindle revs increase. Where I've used a tool as the contact, I 
generally spin the tool backwards so as not to put cut marks on the work 
when doing the measurements. Retracting the brush when the revs go above 
5k or so is something I haven't given any thought to. Its also possible 
that some sort of a weak metallic brush could be laid against the 
spindle, but what happens to it when your are spinning it backwards at 
what would be creep speeds.  Given the full song rpms, I don't see a 
long life for any direct contact solution other than the carbon brush.

As soon as I get the new interface I am building up and running so that I 
have enough i/o, I'll put in home switches just so I can set sw limits 
just short of crashes, then I'll probably write me a corner of the 
workpiece finder using the new probe I installed today, making heavy use 
of g38.2, (not applicable to wood projects though, darnit). Then 
determine those x-y offsets and incorporate them into my code.  The 
natural progression then is to write a skeleton that incorporates all 
that, making the next project after this one even easier.

Basicly, I'm lazy, write it once, run it as many times as I need. ;-)

Cheers Roland, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 



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[Emc-users] New problem, how best to solve?

[Roland Jollivet]

> > Any other ideas out there? Hopefully something that doesn't involve
> > changing tools to use.
> >

I don't know what your spindle looks like, but to make an electrical
connection to it, you could use a piece of earth shield. The woven, braid
type that you find on better quality cables. These are usually plated
copper, or plain copper. Soft and resilient.

Find a place anywhere on the spindle to wrap it a 1/2 turn, pinch the two
ends together, and pulled taut with a very light spring. I think it's
easier, and better than trying to use brushes.
Make a handful while you're at it to replace every 2 years.

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Re: [Emc-users] New problem, how best to solve?

[Gene Heskett]

On Saturday 16 February 2019 14:28:33 Chris Albertson wrote:

> Thinking about this as an electrical engineer,  I'd say don't use DC.
> DC current is as you say blocked by paint and oil films.Use  AC.
> I think a low radio frequency.   Then the DC insulators would act like
> capacitors and pass AC. even while blocking DC.  To detect contact use
> an AC voltage sensor, typically a diode and small capacitor.

The disadvantage there is the rc charge time. This means among other 
things a relatively leasure velocity to the first trip, and a much 
slower 2nd approach, where as in using the dc circuit, one usually uses 
a rotating with the spindle probe so even  if it has some runnout, the 
contact surface is recorded an by the first contact discharging a .1 
ufcapacitor, which takes long enough to recharge that the contacts logic 
zero, is captured and reported to LCNC instantly even if by the time the 
servo thread actually reads it, the contact has been lost again for .9 
milliseconds. The rf circuit, cannot possibly respond in that time frame 
unless the closing velocities are also very slow. The DC method is 
inherently the faster method, but does require a very low ohmage 
connection in order to fully discharge the cap  on a 10 microsecond 
contact.  And we definitely DON'T have a low resistance circuit on this 
machine.

I have one of this old tony's contacts about 75% made, but out of a brass 
tube instead of a steel probe and I'll take the machine out of it by 
grounding the workpiece, and wiring the tube straight to the probe 
input, using the same old cap for storage. The brass is long enough it 
can hit and be bent 1/4" without damage as it will just spring back.

But its been a long day today.  I'll figure out something thats hopefully 
repeatable.   

And I've got to figure what to do Monday as my lady adds another year to 
her journey on this ball of rock and water, making it to her 79nth.

Something she'll appreciate without any physical effort. With copd, 
there's not much of that left.  Sigh...

That said, I think the DC method can be made to work with a separately 
wired probe, with both the ground on the workpiece and the hot on the 
probe wired independently from the machine. Run the probe cable as a 
shielded wire in the cable chain.  At least this chain can be opened to 
add more wire, something none of the other cable chain I've bought can 
do.  Nice!
> I don't know if this is done commercially but the AC method should in
> theory by MUCH more reliable.You can even use very long cables if
> you use strong filters tuned to the frequency. Notice how well the
> current passes from an AM radio station to your radio even over a
> miles-long air gap.
>
> My guess is that a 100 KHz signal would go right through paint.
>
> On Sat, Feb 16, 2019 at 9:46 AM Gene Heskett  
wrote:
> > Greetings all;
> >
> > I've just found that because everything it painted before assembly,
> > apparently including the inside of the spindle motor mount, that a
> > ground to the bed frame can be anywhere up to 2 or more thousand
> > ohms to almost anything else on the 6040, and apparently even
> > includes the spindle bearings as part of the first 50 or so ohms.
> >
> > The net result is that using the workpiece as one contact, the the
> > tool in the spindle as the other for the alignment function is
> > fraught with enough variables I could break a tool against the edge
> > of the workpiece, even damaging the workpiece, before a contact is
> > detected. Since there isn't Z room enough for one of those $65
> > spindle mounted contact detectors, and it would take at least ten
> > feet of ground braid strung thru the cable chains to arrive at a
> > decent ground on the motor housing, which wouldn't solve the problem
> > entirely because of the oil film in the spindle bearings, how the
> > heck do I arrive at a reliable connection that only responds to a
> > contact between the tool and the workpiece?
> >
> > A flying ground lead one could bring up and clip onto the tool would
> > probably work, but sure resembles something Robe Goldburg would
> > dream up as it would need to be long enough to reach the tool
> > regardless of where it is on the table.
> >
> > That, or using a much higher voltage limited to a few microamps so
> > as not to constitute a shock hazard. But basically use it to measure
> > the air gap. I could make that work even before a physical contact
> > was made but thats not a tasty idea in the long view either.
> >
> > Any other ideas out there? Hopefully something that doesn't involve
> > changing tools to use.
> >
> > Thanks all.
> >
> > Cheers, Gene Heskett
> > --
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author)
> > Genes Web page 
> >
> >
> >
> > ___
> > Emc-users mailing list
> > 

Re: [Emc-users] New problem, how best to solve?

[Chris Albertson]

Thinking about this as an electrical engineer,  I'd say don't use DC.
DC current is as you say blocked by paint and oil films.Use  AC.
I think a low radio frequency.   Then the DC insulators would act like
capacitors and pass AC. even while blocking DC.  To detect contact use
an AC voltage sensor, typically a diode and small capacitor.

I don't know if this is done commercially but the AC method should in
theory by MUCH more reliable.You can even use very long cables if
you use strong filters tuned to the frequency. Notice how well the
current passes from an AM radio station to your radio even over a
miles-long air gap.

My guess is that a 100 KHz signal would go right through paint.


On Sat, Feb 16, 2019 at 9:46 AM Gene Heskett  wrote:
>
> Greetings all;
>
> I've just found that because everything it painted before assembly,
> apparently including the inside of the spindle motor mount, that a
> ground to the bed frame can be anywhere up to 2 or more thousand ohms to
> almost anything else on the 6040, and apparently even includes the
> spindle bearings as part of the first 50 or so ohms.
>
> The net result is that using the workpiece as one contact, the the tool
> in the spindle as the other for the alignment function is fraught with
> enough variables I could break a tool against the edge of the workpiece,
> even damaging the workpiece, before a contact is detected. Since there
> isn't Z room enough for one of those $65 spindle mounted contact
> detectors, and it would take at least ten feet of ground braid strung
> thru the cable chains to arrive at a decent ground on the motor housing,
> which wouldn't solve the problem entirely because of the oil film in the
> spindle bearings, how the heck do I arrive at a reliable connection that
> only responds to a contact between the tool and the workpiece?
>
> A flying ground lead one could bring up and clip onto the tool would
> probably work, but sure resembles something Robe Goldburg would dream up
> as it would need to be long enough to reach the tool regardless of where
> it is on the table.
>
> That, or using a much higher voltage limited to a few microamps so as not
> to constitute a shock hazard. But basically use it to measure the air
> gap. I could make that work even before a physical contact was made but
> thats not a tasty idea in the long view either.
>
> Any other ideas out there? Hopefully something that doesn't involve
> changing tools to use.
>
> Thanks all.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page 
>
>
>
> ___
> Emc-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/emc-users



-- 

Chris Albertson
Redondo Beach, California


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Re: [Emc-users] New problem, how best to solve?

[jrmitchellj]

I had a similar issue with a Shapeoko router.
There was no continuity from the spindle rotor to the rest of the assembly.
My solution was to mount a brush above the spindle motor shaft, to make
contact on the end of the shaft, then bring that back to the sense input.
And, yes, I brought a ground wire out to the workpiece to be sure the
circuit would be complete.

--J. Ray Mitchell Jr.
jrmitche...@gmail.com
(818)324-7573


"No problem can be solved from the same level of consciousness that created
it"Albert Einstein


On Sat, Feb 16, 2019 at 9:47 AM Gene Heskett  wrote:

> Greetings all;
>
> I've just found that because everything it painted before assembly,
> apparently including the inside of the spindle motor mount, that a
> ground to the bed frame can be anywhere up to 2 or more thousand ohms to
> almost anything else on the 6040, and apparently even includes the
> spindle bearings as part of the first 50 or so ohms.
>
> The net result is that using the workpiece as one contact, the the tool
> in the spindle as the other for the alignment function is fraught with
> enough variables I could break a tool against the edge of the workpiece,
> even damaging the workpiece, before a contact is detected. Since there
> isn't Z room enough for one of those $65 spindle mounted contact
> detectors, and it would take at least ten feet of ground braid strung
> thru the cable chains to arrive at a decent ground on the motor housing,
> which wouldn't solve the problem entirely because of the oil film in the
> spindle bearings, how the heck do I arrive at a reliable connection that
> only responds to a contact between the tool and the workpiece?
>
> A flying ground lead one could bring up and clip onto the tool would
> probably work, but sure resembles something Robe Goldburg would dream up
> as it would need to be long enough to reach the tool regardless of where
> it is on the table.
>
> That, or using a much higher voltage limited to a few microamps so as not
> to constitute a shock hazard. But basically use it to measure the air
> gap. I could make that work even before a physical contact was made but
> thats not a tasty idea in the long view either.
>
> Any other ideas out there? Hopefully something that doesn't involve
> changing tools to use.
>
> Thanks all.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page 
>
>
>
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>

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[Emc-users] New problem, how best to solve?

[Gene Heskett]

Greetings all;

I've just found that because everything it painted before assembly, 
apparently including the inside of the spindle motor mount, that a 
ground to the bed frame can be anywhere up to 2 or more thousand ohms to 
almost anything else on the 6040, and apparently even includes the 
spindle bearings as part of the first 50 or so ohms.

The net result is that using the workpiece as one contact, the the tool 
in the spindle as the other for the alignment function is fraught with 
enough variables I could break a tool against the edge of the workpiece, 
even damaging the workpiece, before a contact is detected. Since there 
isn't Z room enough for one of those $65 spindle mounted contact 
detectors, and it would take at least ten feet of ground braid strung 
thru the cable chains to arrive at a decent ground on the motor housing, 
which wouldn't solve the problem entirely because of the oil film in the 
spindle bearings, how the heck do I arrive at a reliable connection that 
only responds to a contact between the tool and the workpiece?

A flying ground lead one could bring up and clip onto the tool would 
probably work, but sure resembles something Robe Goldburg would dream up 
as it would need to be long enough to reach the tool regardless of where 
it is on the table.

That, or using a much higher voltage limited to a few microamps so as not 
to constitute a shock hazard. But basically use it to measure the air 
gap. I could make that work even before a physical contact was made but 
thats not a tasty idea in the long view either.

Any other ideas out there? Hopefully something that doesn't involve 
changing tools to use.

Thanks all.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Genes Web page 



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