Broken r8 collet nub (set screw) pm932m

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Well I went to install a collet tonight in my precision matthews pm932m mill and the lil nub that keeps a collet from spinning broke off. I think it's just a pointed set screw. if it is a set screw does anyone know if it's hardened. I'll call pm tomorrow for a replacement just wondering if it happens again and I don't have time to wait for a replacement if I can replace it with a regular set screw thanks :) :) :) 20180314_224629.jpg
 
I'm not sure on a PM, but the same screw on a Bridgeport isn't hardened. On a Bridgeport it's referred to as a "collet alignment screw". It has a 14/-32 thread and a second shorter set screw outside of it to lock the inner one at the proper depth. Here's a link to H&W Machine repair's article on how to replace the screw on a Bridgeport.

http://www.machinerypartsdepot.com/page/487497676

Hopefully the PM is similar enough for it to help.
 
Don’t know about the PM, but on a Bridgeport, it is definitely NOT a normal set screw. The business end and threads are unique…Dave.
 
I've had my PM 932 for 2 years now. Based on many suggestions from members here, the first thing I did was to take that "collet alignment pin" out. I haven't had any problems with anything spinning, and more importantly, haven't had to worry about it breaking off. I've read a few horror stories about that pin (set screw) breaking off and jamming the collet in the spindle. If the collet spins while you are turning the draw bar, then the draw bar or collet threads need to be cleaned. I just barely push the collet with 1 finger up into the spindle taper while tightening the draw bar and thats all it takes. If you search PM 932, there is a lot of info on this from about 2-3 years ago. Happy Machining, JR49
 
none of my 3 milling machines have that pin, it’s not needed. My Rockwell mill, never came with one, I took the other 2 out.
 
I had an Induma (Italian) mill, the pin was sheared when I got it, along with other spindle / quill repairs, I replaced the pin; soon after it got sheard off, never to be replaced again, that was probably 30 years ago. Still it is a daily user and is just fine without the pin.
 
Another thing about the Induma mill that I mentioned above is that the spindle has to be removed from the quill in order to replace the pin, which screws into the side of the spindle and looks like a flat head screw with a dog point. The quill should have been made with an aperture fitted with a threaded plug to access the pin. I also agree that after it sheared for the second time, I never missed it. The reason that I did replace it was that I had to replace the quill housing because some idiot tried to broach a key with the spindle and sheared off several teeth off the quill itself (made of cast iron). I was able to buy the machine cheap because of that, and had a customer who was on a equipment buying trip to Italy in the same city as Induma and brought me back the needed parts.
 
On my Kent, I'm currently battling one that's damaged/tight. It's a ***** to get collets in and out. When I had my shop, we always removed them when the opportunity presented. Never had a problem.
 
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