Instead of a drawbar with a hex end you could use the kind with a spline end like the ones that Kurt sells for their power drawbar. My Bridgeport came with a Kurt power drawbar. I have had it since around 2003. Still using the same drawbar. The socket looks kind of like a torx socket - maybe it is - I never looked at it that close. The Kurt uses butterfly impact kind of like yours. It just uses regulated air pressure. I just let it drive the drawbar for about 1 or 2 seconds. It has never stripped and I have never replaced the drawbar. Tooling is NMTB 30. Home shop use only.
http://www.machineability.com/Bridgeport_series_II.html John On Mon, Nov 22, 2021, 3:39 PM John Dammeyer <jo...@autoartisans.com> wrote: > Hi Mathew, > I want to be able to swap easily and quickly between R8 and TTS. Here's a > selection of some of the tooling. > > http://www.autoartisans.com/mill/ToolSelection.jpg > > There's a full set of R8 collets of course. The spring loaded Tap Holder > has a 3/4" shank so it really just needs a TTS collar to make it full TTS. > The two gear cutter arbours for the different sized cutters. Face mill. > Changing from a 1/4" drill bit means I have to swap out the TTS to install > the R8 based expensive 16mm JT3 ball bearing chuck. > > To change completely over to TTS is expensive. To change to a mill with a > NMBT or CAT cone type is really expensive. The lowest cost power toolbar > system was the butterfly wrench and air cylinder. Cost escalated as the > ordered electric pneumatic valves just never showed up from China so I went > local. Not really expensive but it adds up as do all the fittings. > > At this point I could see spending as much as $150 Cdn. for the planetary > gear and stepper combination. Still way less expensive than fully > switching over to TTS which I probably will over time but not all in one > shot. And I'm not sure the TTS wouldn't slip with the 5/8" chuck holding > a 1" reduced shank drill bit. > > First step now is to wait for the 12 point deep socket. > > John > > > > -----Original Message----- > > From: Matthew Herd [mailto:herd.m...@gmail.com] > > Sent: November-22-21 10:49 AM > > To: Enhanced Machine Controller (EMC) > > Subject: Re: [Emc-users] Spindle positioning. > > > > Hi John, > > > > You don�t need pull studs on the R-8 collets, just thread the draw bar > into the collet. Either until it stops or loctite the draw bar at > > the right depth. Then use a Belleville washer and air cylinder setup > like Andy�s. > > > > Matt > > > > > On Nov 22, 2021, at 1:32 PM, John Dammeyer <jo...@autoartisans.com> > wrote: > > > > > > ?It's the lowering of the wrench that I don't have a lot of control > on. It's pushed down hard enough to keep the draw bar on top of > > the spindle so as it turns it pushes the sometimes a bit stiff R8 all > the way down and out. If it's allow to move upwards (or I haven't > > locked the quill) then the drawbar may unthread but I then have to push > on the draw bar. > > > > > > A sensor on the Z down may be what has to happen. Then repeated tries > with blipping the air wrench until it goes down all the > > way is an option. > > > > > > Making a draw bar from oil hardening steel and hardening the head a > bit so it doesn't get carved away and ends up more slippery > > might also be a requirement. > > > > > > John > > > > > > > > >> -----Original Message----- > > >> From: andy pugh [mailto:bodge...@gmail.com] > > >> Sent: November-22-21 5:41 AM > > >> To: Enhanced Machine Controller (EMC) > > >> Subject: Re: [Emc-users] Spindle positioning. > > >> > > >>> On Mon, 22 Nov 2021 at 08:03, John Dammeyer <jo...@autoartisans.com> > wrote: > > >>> > > >>> One still has to line up the socket to the hex head of the drawbar. > And since it can be at any position relative to the spindle the > > >> sensing has to happen against the hex head. Rotate spindle until hex > head is at a known position. > > >> > > >> How about: > > >> > > >> Lower the wrench, but don't turn it on. > > >> Rotate the spindle until the wrench drops down to the "engaged" height > > >> (sensor on the slide) > > >> Then operate the wrench. > > >> > > >> -- > > >> atp > > >> "A motorcycle is a bicycle with a pandemonium attachment and is > > >> designed for the especial use of mechanical geniuses, daredevils and > > >> lunatics." > > >> ? George Fitch, Atlanta Constitution Newspaper, 1912 > > >> > > >> > > >> _______________________________________________ > > >> Emc-users mailing list > > >> Emc-users@lists.sourceforge.net > > >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > Emc-users@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
