Worn Lathe Spindle Bearing????

[cfellows]

A week or so ago, soon after I replaced the ball bearing race in my lathe headstock, I started noticing an increasingly loud clicking sound whenever I started the lathe.  And, it was definitely proportional to the speed of the spindle.  My first thought was, crap, one of the spindle bearings was going south on me or a piece of swarf had found it's way into the new tapered roller bearing I had just installed. 

This morning I decided to do some troubleshooting and determined the noise was coming from the motor, not the spindle.  That brought some relief, but now I was concerned that the brushes on  my 1hp DC motor of unknown vintage might be worn out.  Finding replacement brushes would surely not be an easy project. 

I removed the rear plate from the motor, a task that turned out to be surprisingly easy and discovered that the brushes and armature were in pretty good shape with plenty of wear left in them.  So, I reassembled the motor and using a length of polyurethane tubing as a makeshift stethoscope started trying to home in on the source of the noise.  Now it seemed to be coming from the front of the motor.  Probably the front bearing.  But the noise seemed to be  somewhat forward of said bearing.  Then I spotted the drive pulley and wondered... sure enough, the set screw which tightens against the key had worked loose.  I cinched it up nice and tight and the noise disappeared. 

I might add, at this point, I have been delighted with the performance of the new tapered roller bearing on the spindle.   I can take deeper cuts in steel without chattering and the finish is noticeably better than before.  Really happy with the upgrade!

Chuck

[Bertie_Bassett]

glad to hear it was a simple fix 

i tend to always assume, the worse when i find a problem that way every now and then i'm pleasantly surprised when its something simple.

[b.lindsey]

Good to hear you got it sorted out in short order Chuck. Such noises can be worrisome for sure or annoying at the very least.

Bill

[cfellows]

My celebration was a bit premature.  A new, albeit quieter noise has surfaced, apparently masked by the loose pulley noise.  This new noise is definitely the rear spindle bearing.  The good news is, it's a fairly common, inexpensive bearing to replace, 75x45x16mm. 

[b.lindsey]

Well drats!! This was a new bearing though too right?

Bill

[steamer]

My celebration was a bit premature.  A new, albeit quieter noise has surfaced, apparently masked by the loose pulley noise.  This new noise is definitely the rear spindle bearing.  The good news is, it's a fairly common, inexpensive bearing to replace, 75x45x16mm.

What grade are these bearings?  and are they angular contact, or Deep groove?

Dave

[cfellows]

Bill, I replaced the front bearing with a tapered roller bearing.  The rear bearing, which is making noise, hasn't been replaced in the 25 years I've had the lathe.  Dave, this is not an angular contact bearings, just deep groove.  I might consider replacing it with a tapered roller bearing if I can make it work.

Chuck

[steamer]

Definitely doable.   The preload is the key.
Set it warm!

[cfellows]

I've ordered both a deep groove ball bearing and a tapered roller bearing. 

The pre-load on my spindle is provided by 4 belleville washers with an unloaded thickness of 11mm.  Since the tapered roller assembly is 4 millimeters thicker than the ball race, I think I could just remove 2 of the belleville washers and still have enough pre-load with the 2 remaining belleville washers.

The alternative would be to keep the 4 washers and shorten the sleeve that separates the inner race and the rear spindle nut which holds it all together.  Actually, this might be a better option.  I'll just make a new, shorter sleeve and keep the original for backup.

I'm definitely going to try the tapered roller.  If it works, I'll just keep the new ball bearing as a backup.

[steamer]

Knowing you have a logan, the original bearings were probably angular contact duplex pair, front and rear.     Can you get the correct bearings for the lathe?

What's the part number?

Dave

[gldavison]

Your success here has renewed my interest in doing my 10" Logan. Have replaced spindle bearings twice, with no improvement in chatter. I'm interested in how you sealed both side of bearings. Did you have to make holders, or were you luck enough to find seals that fit existing bores?