Mill spindle play???

[Hukshawn]

I just noticed that there is vertical play in my Bridgeport clone spindle. I can move the spindle up and down almost 003".
That would very much explain the noisy milling, chatter, and rough surface finish I've experienced with some indexable mills.

There's got to be a way to take up that slack. How? Where?

 

[T Bredehoft]

I use the spindle clamp whenever I'm milling.

 

[Hukshawn]

Nope. Not that. The quill lock is always engaged when I mill. It's actually in the spindle itself, not the quill.

 

[cathead]

Hukshawn,

Do you have lateral play(side to side play) as well as up and down movement? In any case, I would
be suspect of bearing wear as normally there is no discernable movement in either axis. It's possible
that the bearing holders could be loose causing vertical movement I suppose. The bearings in the
quill are very close tolerance units and can be purchased in several levels of precision (>=+$$$). It's possible
you may have to replace the bearings to "take up the slack". Good luck on the project.

 

[Hukshawn]

My mistake in using the word lateral. It is only vertical movement. It is tight side to side.
I guess I have to take the power head off to get a better look.
There is a lock ring at the top of the spindle. When I rebuilt the head I tightened that ring till snug, but I wonder if some gaps have worked them selves out since and I have to re-snug that nut. Does that seem at all likely??

 

[cathead]

Huk,

At this point, you know there is play. I know you will find it. You are that kind of guy.

 

[4GSR]

Sometimes, when you assemble a spindle and it has been put in service and you start to get the axial end play as you are talking about. You have to go back in and re-tighten the bearing lock nut on the spindle along with the retainer cap on the bottom of the spindle. That should eliminate the problem. If not, then you have to go in and place a spacer between the bearings that fit to the outer race of the bearing. A 0.003 thick spacer should do it. Re-install the spindle and run it again and see if that helps. May need to put up to a .010" spacer to eliminate the slop. But be careful, get the bearings too tight, they will heat up and become toast in a very short time.

 

[Hukshawn]

Ok. I'm glad my thinking was on the right track.
That's a lot of disassembly to find out I was wrong.
Uhhg. Back into the beast I go!

 

[Hukshawn]

The locking nut was exactly what it was. Spins freely but no lift now. Turned it almost 3/4 of a turn!
I guess to be expected after a rebuild. I didn't see any torque specs for this nut, so winging it was what I had

 

[Hukshawn]

Holy crap on a cracker!
I'm speechless...


There's that cheap Chinese face mill I was having so many problems with. Mind the finger prints where I was feeling the finish. There are still some little chatter marks, but NOTHING like what was there before. And it's QUIET! What an incredible difference....