Milling collet arbor jammed in milling machine

[KWILParticipant @kwil]

Spot on Chris, that little peg in the R8 setup just stops it turning until the taper bites, that is if the peg has been correctly set in place and is not worn.

[Chris TriceParticipant @christrice43267]

Surely if a collet needs a driving peg because it can’t  ‘grip’  the inside surface of the quill, then it can’t grip the cutter firmly enough without a peg either? This must apply to all taper collets. The only exception is when using something like an Autolock chuck but then locking the positioning of the cutter in one of those is achieved by screwing the cutter up hard against a stop before gripping it anyway. Plain taper collets rely purely on friction and nothing more.

[KWILParticipant @kwil]

Chris, an R8 does not NEED a driving peg, it is there as a convenience to stop the collet moving whilst pulling it in. Believe you me, if you really pull on the drawbar, an R8 will be quite difficult to drive out. I use an air powered drawbar and can control the torque.  I also use an Autolock in the R8 ended Quill!

[DMBParticipant @dmb]

Julian,

“Been there, done that”

My long-term solution as follows.

Trapped nut system works like a dream – try it!

I made new drawbar with nut just touching top of mill spindle, remove, cross-drill + pin.

Large AF hex bar bored out to fit over top of mill spindle and locked on to it with 3AAllen key grubscrews.The rest of it drilled right thro` clearing size for drawbar thread. Make new smaller AF nut, taller than standard, fit  on top end D-bar + wind down to just touch top of large AF nut, cross-drill + pin.

John 

[DMBParticipant @dmb]

Julian,

Further to prev. post,  Taller nut at top so spanner fits without being obstructed by rivetted cross-pin. I milled small flats on 3 corners of large hex to start tap drill, giving thicker metal to receive the grubs.

Spanners on the 2 visble hex nuts and twist, causes drawbar to shove the MT forward

 out of its socket.

John.

[Sub MandrelParticipant @submandrel]

I don’t know if you can do this on the Warco, buthis was the solution for my ARC X-2:

 

I thinned down the top lock nut on the spindle, allowing me to fit a tall steel cap on top (left hand thread – I think it is 2mm pitch but check this!) This cap has a large central cavity but a smaller hole on top. I made up a draw bar with a 1/2″ thick steel disc silver soldered on it and made a 3/8″ BSW therad at one end and an 8mm square on the other.

 

 The dimensions are such that when  tightening the drawbar using a spanner on the square the disc clamps tightly on the end of the spindle. Fit the cap over the drawbar. When you want to remove the taper, screw the spindle out and before it fully disengages the disc pushes up on the inside of the cap. With modest force even the tightest taper pops loose with the chuck etc. safely dangling on the end of the drawbar.

 

Yes there is some cut’n’try to get the dimensions spot on, and yes I really MUST get around to making a metric one to match!

 

Neil

 

 

[Chris TriceParticipant @christrice43267]

Posted by KWIL on 04/06/2010 09:28:51:
Chris, an R8 does not NEED a driving peg, it is there as a convenience to stop the collet moving whilst pulling it in. Believe you me, if you really pull on the drawbar, an R8 will be quite difficult to drive out. I use an air powered drawbar and can control the torque.  I also use an Autolock in the R8 ended Quill!

Don’t worry. We’re on the same song sheet. My vertical milling machine is an R8. I generally loosen the drawbar a  turn or two and then tap it with a hide mallet to release the collet. It certainly won’t fall out and that’s after tightening it only modestly in the first place with a ring spanner and holding the driving belt.

[drjohnParticipant @drjohn]

What are all you old women on about – Julian got the taper out 2 pages ago – and there was no mention of R8’s it was Morse #3 taper! –

 

Move along now – nothing more of use here!

 

DJ

[Chris TriceParticipant @christrice43267]

Actually the discussion was broadened to the nature of collets generally but I’m happy to discuss the very specfic nature of one size of morse taper collet… if that’s OK?

 

(edit for typo)

Edited By Chris Trice on 06/06/2010 16:27:38

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