Drawbar stuck

[grantj]

I have a PM949TS (Bridgeport clone) and I have gotten my R8-ER32 collet holder stuck on the draw bar.


I'm not sure how I managed to do this. My guess is something to do with using backgear to hold the spindle from rotating while tightening the ER collet holder, and I turned the mill on before moving back to the normal gear by accident. But I've done this before and the drawbar did not get stuck. (I'm not sure if I did this right before it got stuck)

The drawbar does not budge in the slightest. I've tried the normal 16"? double end wrench with a mallet and an pneumatic impact wrench. I've also tried letting the spindle run for 10mins to warm up, but still nothing.

Last resort is to cut the head of the drawbar off and hammer it out. But I'd like to avoid that.

The R8-ER32 collet holder was in good shape with no burrs/dings and had been in and out of the spindle a few times before I got the drawbar stuck. I don't feel like I over tigthened either the collet holder or the drawbar. I had made a few tool changes between the ER collet holder and a drill chuck before this happened.

Any advice on what I should try next would be appreciated.

 

[raptor2013]

I would keep trying the wrench and maybe a two pound hammer. I think cutting it off you might get into more problems.

 

[B2]

Just a thought.... The collet and draw bar threads are loaded under tension. This tension force results in high frictional forces and are the reason these hold together normally. However, it sounds like your friction is extreme or maybe the metals have welded a bit. Cutting the draw bar sounds desparate. Try unloading the tension by lowering the collet face on to a sold surface resulting in a force upward. (i.e Lower the head until the collet is being pushed up hard by a block (hard wood?) mounted on the table, hence removing some or a lot of the tension force. Tap down on the top of drawbar as you try to turn it loose from the collet. It soulds like you would be ok with the load on the block being sufficent to dig into the block. If there is still a tool in the collet, and if possible, let the tool stick through the block (a hole) so that the pressure is on the collet and not the tool. You may need an extra set of hands or at least a clamp to hold the block from turning.

Good luck

Dave.

 

[tjb]

Based on my visualization of your problem, this probably won't work, but if there is still a tool in the collet, you might try grabbing it with a pipe wrench or vise grips while turning the drawbar with your other wrench or an impact wrench. (This would probably require an assistant.) The tool will probably slip, but that may actually be a good thing - some of the pressure may be released. Also, if there is enough of a lip exposed on the collet, you could grab the collet itself with the pipe wrench or vise grips.

Absolute WORST approach would be to weld an extension of some sort onto the collet to allow you to grab it with a second wrench. I wouldn't dare try that without input from far more seasoned veterans than me.

Good luck,
Terry

P.S.: I'm just now noticing your original post is about three weeks old. Did you get it out? How'd you do it?