A Question For Power Drawbar Users

[SCzEngrgGroup]

I don't have a Tormach, but I do have a Chi-wanese Bridgeport clone I've CNC'd, including a unique power drawbar that uses a stepper motor to tighten and loosen the drawbar, allowing my to swap R8 and TTS tools with almost equal ease. I'm curious if any of the Tormach PDB users ever have problems with the collet not popping free. About once a week, I find I have to remove the collet, and wipe a little grease on the taper, or the tool will not release when the PDB activates.

Regards,
Ray L.

[MFchief]

Hi Ray,

I haven't had a problem with sticking as you described, but I'm not certain if by popping free, you mean opening enought to release a tool shank, or dropping out of the spindle? Most Tormach users with PDB's, use TTS tooling and most of the time, don't actually remove the collet. I use anti-seize compound, as recommended by Tormach, rather than grease, you might want to give that a try. You probably know already, but you can get a small tube at almost any automotive store, I use Permatex brand, but I would think almost any brand would work equally well.
Good Luck
Terry

[Sp-4renegade]

I never had a problem. yet I only have 300 hours on my mill. Lots of tool changes though cuz most of my work is MDI and one type proto types or odd things other shops wont do. Remember the old Timax commercials? Where they put the watch on cat tracks and it keeps on ticking? Thats they type of work I do. I even made an addapter to go from 3/4" to 1" tooling and still holds up. The one problem I had machining harden steel was the tool holder pulling out. That problem has been cured, now all runs 110%

[philbur]

That sounds very interesting. Would it be possible to post some photos of the mechanism?

Phil

.... including a unique power drawbar that uses a stepper motor to tighten and loosen the drawbar

[zephyr9900]

I'm not Ray, but have read his drawbar thread over here.

Randy

[TXFred]

I don't have a Tormach, but I do have a Chi-wanese Bridgeport clone I've CNC'd, including a unique power drawbar that uses a stepper motor to tighten and loosen the drawbar, allowing my to swap R8 and TTS tools with almost equal ease. I'm curious if any of the Tormach PDB users ever have problems with the collet not popping free.

It's not an issue. The Tormach's design pushes on the drawbar, and so the collet is pushed out of the taper. Occasionally the collet begins to stick, and makes a snapping sound as it comes out of the taper. That's a sign that it's time to add some more lubricant to the collet.

Frederic

[philbur]

Thanks for that Randy.

Phil

[SCzEngrgGroup]

It's not an issue. The Tormach's design pushes on the drawbar, and so the collet is pushed out of the taper. Occasionally the collet begins to stick, and makes a snapping sound as it comes out of the taper. That's a sign that it's time to add some more lubricant to the collet.

Frederic

Mine presses down on the drawbar as well, but perhaps just not with as much force as the Tormach PDB.

I'll give anti-sieze a try. I have some around here somewhere, but hate using it, because it seems to have an uncanny ability to get all over EVERYTHING, no matter how little you use.

Thanks!

Regards,
Ray L.

[SCzEngrgGroup]

That sounds very interesting. Would it be possible to post some photos of the mechanism?

Phil

I've been using the drawbar for a month or more now, and could not be happier. With the exception of the occasional stuck collet, it has worked flawlessly, and makes tool changes quick and painless. No problems at all with generating more than enough torque to keep the tool in place. It's only exhibited pull-out once, and that was before I'd gotten the software finished, and it had not properly tightened that one tool. Otherwise, it has been pretty much perfect, and it's really nice being able to swap both TTS and R8 tools in and out with equal ease (R8s just take a few seconds longer).

Regards,
Ray L.

[Steve Seebold]

I got the PDB when I bought my machine. So far the only problem I have had was the flange that screws on to the spindle shaft has come loose and spun up the shaft so high that the PDB wouldn't/couldn't release the TTS holder.

A good cleaning and a little blue locktite fixed that problem about 6 months ago and I haven't had a problem since. I take the R8 collet out about once a month to clean it and reapply antiseize around the taper and the 7/16-20threads.

[philbur]

Is it not possible to design a captured drawbolt arrangement such that it is restricted from moving upward as it is unscrewed, thus pushing the collet downward.

Phil

With the exception of the occasional stuck collet, it has worked flawlessly, and makes tool changes quick and painless. .

[SCzEngrgGroup]

Is it not possible to design a captured drawbolt arrangement such that it is restricted from moving upward as it is unscrewed, thus pushing the collet downward.

Phil

Phil,

Yes, it certainly is, and, as long as there is enough air pressure, that is what mine is intended to do. But when the collet gets stuck, it sometimes gets REALLY stuck.

Regards,
Ray L.