r-8 locating pin broke

[jarr88]

well the other day i was changing a tool on the mill and i noticed the draw bar was kinda tight and was seizing .so i sprayed some wd40 down the spindle and started to losen the drawbar agian and i heared a kinda snap noise and the collet lossened off..So no big deal but when i whent to put the second other tool into the spindle the r8 locating pin was broken cause the collet just moved freely when i whent to tighten the drawbar..Its a milldrill from busybee and i have warranty so i whent to talk to the guy at busybee and he didnt really have an answer other than he will call main office about the problem..But he did say to take out the spindle by un tighting of the top nut on the top of the pully and this i could not do it is so tight and wont budge so what do i do...

thanks

[Bubba]

Might not be a problem, there was a recent thread on the zone about that exact subject and many are of the opinion that it is NOT mandatory and the only real reason to have it is to assist with loosening and tightening the collet. It is NOT there to drive the collet and prevent spinning under load. That is what the friction force of the taper is fore.
Having said that, I have seen references that the pin is either a "set screw" in a tapped hole or simply a pin that is shoved into the hole in the quill.

My question would be "why did it snap". Have you not been tightening the drawbar enough and relying on the pin to do the driving or did something happen to have the collet shear the pin?
Just food for thought.

[Capt Turk]

Mine snapped the pin off right after I got the mill. I've been using it without the pin for over a year now. It hasn't been a problem, unless I forget to tighten the drawbar.

[widgitmaster]

On a full sized Bridgeport mill, the spindle nose cap has a small set screw, when removed the cap can unscrew off the spindle.
Under the nose cap there is a setscrew that holds another setscrew with a round pilot that acts as the key for the R8 collet's. When both of these setscrews are removed, a new pilot screw can be installed and the 2nd setscrew is used to lock it in position so the col lets slide freely.

I hope this is a similar situation on your machine!

Widgit