[gcude]

I may have previously noted how noisy my Y-axis movement is. It sounds like an angry cement mixer when moving Y+ (table moving toward me), but is fairly quiet going back in the Y- direction. From reading everything, everywhere I can, I looks like thrust bearings need replacing. I have seen in a previous post from Bloke about the bearing numbers, but I have not found any diagram or step-by-step of how to get to them. I removed the cover plate in front of the Y servo at the front of the mill, but don't see any thrust bearings there, unless I don't know what to look for. Does the table have to be removed to get to them? Thanks in advance for all the help found here.

[bloke]

Have you got the linear rail or box way version?

[gcude]

Linear rail.

[bloke]

Nice!
Remove the Y front slide cover.
Put a mark on the coupling and on the ballscrew.
Slacken the four M6 hex bolts on the ballscrew side of the coupling to release the taper lock.
Undo the four screws holding the motor to the housing and then remove the motor.
Undo the locking set screw on the bearing nut.
Undo the bearing nut.
Remove the four screws holding the housing in place then slide the housing off the ballscrew.
Nip over to the bench with the housing and remove the bearing retainer plate.
Tap the old, knackered bearings out of the housing noting direction of mounting (look for whether the bearings have open faces outwards or inwards).
Clean everything up nicely.
Clean out the preservative oil in the new bearings (unless they are pre-greased) and then load with about 1.5 cc of new grease.
Mount the new bearings the same way as the old ones lining up the marks on the inner and outer rings if they have them.
Replace the retainer ring and nip the screws and tighten them gently and evenly.
Refit the housing onto the screw.
Lock the nut back up checking the screw doesn't lock tight as you do it up. There is no pre-load to worry about as it is ground into the bearings. Tighten the locking set screw.
Refit the screws to the housing and wind the Y as far forward as you can and pinch the housing screws to make sure the housing is aligned with the ballscrew. Wind the Y back again and tighten the screws properly.
Refit the motor.
Line the marks on the coupling and the ballscrew. You will be within a few thou of your old home position that way.
Tighten the four coupling screws.
Check it all runs ok and calibrates in roughly the right place.
Sling the Y cover back on.
Pour beer.
Sit back.
Chill.

[gcude]

That's a nicely written set of instructions. Thanks!

[bloke]

No probs, fella.
It's quite a nice little job to do. If it looks easy, that's because it is!

[gcude]

Bloke,

Your instructions say,

"Undo the locking set screw on the bearing nut."
"Undo the bearing nut."

There were 2 set screws (90 degrees apart) and I removed them, but how does the bearing nut "Undo"? Is it a sliding fit, taper fit? I have taken 6 socket-head bolts out of the cover on the other side of the housing/base-casting and those were holding on a retainer plate on the screw side of the casting. Still the housing and nut is not coming loose from the screw. I've only been able to separate the housing from the base casting by about 13mm. Hate to bugger anything up at this point.

Please enlighten me further and/or point out my error(s).

Thanks,
Gary

[bloke]

The locking nut is just an ordinary threaded nut but with four sides instead of six. Just loosen the two set screws and then undo it with a spanner whilst holding the ballscrew still. It's a right hand thread. Once it's off, the housing should just slide off the screw.

[lixingwen1987]

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