Signs Of Bad Spindle Bearings?

E

eeler1

Dang, buggered that up too!!
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For those that have replaced them, what tipped you off that you needed them?

Chatter? Difficulty with way alignment? Noise? Taper cuts?

I have substantial deflection on 1" drill rod, can push it in all directions about 0,025+", when chucked in 3 jaw, bout 8" from chuck. Has me concerned.
 
As well it should! Put a dial indicator on the chuck body itself and push and pull the chuck around while turning it by hand.
Is there any unusual noise? Also check by pushing and pulling inline with the bed. You might try prying with a 2x4 or
some similar soft but rigid tool. There should be some flexure even with 1" drill rod, but maybe .0005" or so, unless
you are using a (live) center held by the tail stock.

Chuck the Old Grumpy Guy
 
What make and model is your lathe?
 
Hey eeler1, we are neighbors :) Does the machine have sleeve bearings, ball bearings or tapered roller bearings ?
 
OK. I don't have access to a parts manual on the Logan 11" but do have a couple of catalogs that say it's spindle is similar to that of the 12" at least insofar as the bearings are concerned. 8" from the front of the chuck must be on the close order of 12" from the right-hand spindle bearings. Which I would guess is on the close order of the distance between the left and right-hand bearings. And although one could create a scenario using a brand new right-hand bearing and a worn out left-hand bearing where you could get 0.025" vertical movement due only to wear in the left-hand bearing, the odds are that you need to replace both sets of bearings. Assuming that the chuck jaws are not bell mouthed and a few other assumptions, the radial clearance in the vertical plane in the right-hand bearings is probably on the close order of 0.010" to 0.012". Which I would call excessive.
 
Randy,

It has ball bearings, but I don't know how many. Either three or four races.
 
wa5cab said:
Randy,

It has ball bearings, but I don't know how many. Either three or four races.
Click to expand...

Good ! The front of the spindle likely has a pair of angular-contact ball bearings, the rear a simple ball bearing. The front bearings can be adjusted to reduce spindle play ... do you have the procedure for bearing adjustment and have you attempted to make the adjustment ?
 
Well, it might or it might not. I would have thought that some 19xx owner would have piped up by now, but I do know from some catalogs that I have that the (or at least several) 12" has four bearing races on the spindle. The two toward the left end are separate bearings separated by about a diameter. The two at the right end are separated by about half a diameter but the way in which they are drawn doesn't make it clear whether there are two single-race bearings separated by a wide spacer, or the whole thing is one double-row bearing. I do know from a lengthy thread here some time ago that one model (maybe the 200) has two bearings. A single-row at left end and a double-row at right. You cannot adjust the preload on a double-row bearing.
 
Randy, I wish we were neighbors, but I relocated down to the Sacramento area for a few years. Really miss Arcata, especially when it gets over 90 degrees here. Anyway, I will try to figure out how to change my profile.

Task at hand, I was getting chatter and rough cuts the farther from the chuck I got, yeah, to be expected maybe but still concerning. So thats when I tried chucking some steel and pushing it around.

I just went back out and put a dial indicator on the chuck, used a shovel handle (no 2x4 in house) to put upwards pressure on the chuck, and get about 001" of deflection. This is without warm up.

I believe there are two ball bearings at the business end of the spindle, and one at the outboard end, with no way to adjust the bearings.

What I was looking for was a test to see if the bearings are up to specs or not, so maybe the 1/1000" deflection is ok, maybe it indicates bad bearings.

There's another thread here about logan bearings. I'd prefer not to replace them as they are kinda pricey.
 
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