Strange R8 Collet Problem.

rdsii64

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I have a very weird problem with my mill. When ever I have to remove or reinstall my R8 shank drill chuck, it goes off with out a hitch. All I have to do is lossen the draw bar a half turn, give a light tap with a hammer or rubber mallet, then back out the draw bar and easy peasy its done. I actually have to hold my hand under it to catch it when it falls out. Its that easy.

My R8 collets are another affair. Installing a removing an R8 is such a fight I have actually galled the threads on my draw bar and had to replace it. Inf fact I actually have to tap the collet up into the spindal so the draw bar can thread into it. I know this can't be right I just don't why, nore how to fix it.

If it will help figure out the problem, my mill is your typical bench top X2 mini mill with an air spring and belt drive conversion.

I have considered just going to end mill holders and swearing off collets for good but I'm not sure I won't hve this issue with an end mill holder.

Please advise
 
Check the threads on the draw bar. Chase all the threaded holes in the collets. Check the keyway pin for correctness. Check the collets for burrs. That should do it…Good Luck, Dave.
 
After reading the other artical I might be able to get away with sanding off a half thousandth as a temp. fix untill I can get some new 9 (read better ) collets. Now since I don't have a lathe I have to figure out how I'm going to do this.
 
I have had to remill a few keyway slots on R8 collets through the years because of not fitting. The slots seemed to be the most common problem. I have also had to replace a few thread inserts in a few because they were case hardened which caused the threads to become tight and caused the threads on the drawbar to gall and strip. I usually try the drawbar in all new collets before even tying then in a machine. If tight I check to see if it has a threaded insert that can be changed (usually only the better r8 collets have the inserts ). The next thing is how it fits into the spindle. Sometimes I will use some bluing to see where it is binding before I go further.
 
After reading the other artical I might be able to get away with sanding off a half thousandth as a temp. fix untill I can get some new 9 (read better ) collets. Now since I don't have a lathe I have to figure out how I'm going to do this.
You could insert a 7/16 collet in the mill, then mount a 7/16"-20 rod in the collet. Screw a nut onto the threaded rod, then screw on the collet you want to work on using the nut to lock it in place. You could also use a drill chuck to hold the threaded rod but if you have a keyless chuck be sure to pay attention which direction you turn on the spindle so it doesn't unscrew.
 
Yup, on my mill that keyway was the stupid part. On my lathe the stupid part was the chuck guard. Both annoyed the hell out of me & had to get thrown away. I won't recommend it as I don't want to get arrested by the safety police but I'm no longer hating life without them. :D
 
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