Drill / Mill Spindle-to-Pulley Spline Fit

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jdeng

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Thought I'd pull this out of another thread I've been getting help on as it's a new topic.

I refurbed the spindle bearings in my Grizzly G0935 drill mill and after re-assembly was hearing a lot of knocking. I've narrowed it down (I think) to the play between the splined-shaft of the spindle and the splined-housing of the pulley. The play is pretty significant in all three rotational axes: I can pitch, roll ,and yaw quite a bit before the splines engage.

Is this to be expected? Could it be the cause of the knocking sound? And the heat in the pulley (it gets 120F hot)?

Appreciate any help and experience.
 
Did you not notice this as bad before the bearing refurb? Some play is expected but it should be within reason
Did you perhaps forget a snap-ring that would have controlled the play in the axial direction? Could one of the parts have cracked?
Was there a lot of grease previously that you removed? Something must be different if the difference is very noticeable
 
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Can you see significant wear on the splined shaft (spindle) or is the pully wallowed out?

Contact Grizzly and ask if a replacement parts are available and co$t$.

Alternatively, apply grease to the affected area and see if that calms things down enough?
 
Thanks for the quick responses. Good to know that it seems a little fishy to y'all.
  • I didn't notice anything before the refurb, but I have a vague recollection of knocking the very first time I put power on it. There was always play / backlash if I rotated the pulley by hand, forward and then backward. enough that I felt it was strange. But figured lash is no big deal.
  • No left-over parts on the bench and I should clarify: there is no axial play. The play is the ability to rock the pulley assembly on the spline shaft
  • There was a lot of grease! I assumed it was just a sloppy assembly on the factory floor. I regreased the splines but nothing near what was on there. Is this an acceptable way to remove slop? seems...sloppy.
  • No wear that I can see.
I'm already in talks with Grizzly to 1) agree that their drawings do not match my machine (see forementioned thread) and 2) that they owe me a bearing. Will also chat them about this...though I would imagine they either need to send a matched spindle and pulley or I'm going to end up with some version of the same issue.
 
Probably the excess grease was masking the issue, and no, it's not an acceptable method to remove slop
 
Can you confirm what bearing is in the pulley assembly? The manual indicates a single row ball bearing, that doesn't seem like enough to handle the pull of the belt without pulling it out of vertical, especially if the belt tension was too high. My mill has a double row ball bearing there and there is no play in any direction and only a slight rotational play between the splines. I'm wondering if the cage in that bearing broke, it will give you the noise you are hearing if the balls are able move around.
 
6007Z and you were right: it's shielded not sealed.

But your post made me realize that I think I have been misleading y'all a bit here. when the pulley assembly is installed there is no play between the pulley and splined-shaft (except the lash around the spindle axis). when I disassemble and match them *off of the machine* is when I notice the play.

So I'm feeling rather foolish, sorry for the red-herring. Still can't figure out where the knocking is coming from.
 
Ok, that makes me feel better, I thought you were getting all that play while installed. Troubleshooting takes eliminating one step at a time, so now time to look in another direction.
 
Well this is starting to get pretty frustrating. I've disassembled and reassembled the spindle a third time. Everything looks good. Installed and it's rattling like a banshee. The spindle and housing stay relatively cool over 10 minutes of running at 3k rpm, but the pulley assembly gets toasty. I guess I have to assume it's the pulley bearing? Some strange observations below:
  • engaging the quill lock makes the rattling worse
  • the rattling is worse with the high speed belt than the low speed belt (at the same rpms). the high speed pulley is *closer* to the pulley-bearing so this makes very little sense to me.
  • if I use the downfeed while the rattling is occurring, the spring return to z-0 is jerky. it is not jerky if the motor is off.
video of the rattle (with the high speed belt on). obviously can't run the machine like this. I'm in no rush but I had imagined this was going to be a 2 hour job!

I suppose the next logical step is to replace the pulley bearing but any insight from you folks would be very much welcomed.

View attachment 20240908_5913.mov
 
I think the pulley bearing is bad, it is fairly cheap, so worth replacing with a good quality one.
 
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