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Live Center Bearing

thestelster

thestelster

Ultra Member
Premium Member
For a number of years now, my lathe live center has been feeling gritty. So I decided to take it apart and have a look.

Well, to my surprise, one of the thrust bearing races was put in backwards so that the balls were sliding on the flat side instead of the grooved side!

There was quite a bit of caked on crude in the thrust bearing cage which holds the balls. Once all cleaned up, and reassembled with the race in the proper orientation, the spindle rotates smoothly.
 

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thestelster said:
It wasn't difficult to disassemble, but putting it back together is a little more difficult becasuse there were 2 sets of roller bearings in a split cage. As well as trying to determine the correct preload.
Click to expand...
What is the correct type of lube for a live center? Mine was a little less lively than I thought it should be so I just stripped and cleaned it. It had some type of fairly light grease in it but very little.
 
Doggggboy said:
What is the correct type of lube for a live center? Mine was a little less lively than I thought it should be so I just stripped and cleaned it. It had some type of fairly light grease in it but very little.
Click to expand...
I don't imagine it matters a whole lot as long as it is decent grease you'd put in a wheel bearing. I used redmax grease on the last center I did.
 
I'll let others who have exact information chime in. But if they don't, I'd use a lithium high pressure sealed wheel bearing grease. It should last forever.
 
Doggggboy said:
What is the correct type of lube for a live center? Mine was a little less lively than I thought it should be so I just stripped and cleaned it. It had some type of fairly light grease in it but very little.
Click to expand...
I honestly don't know what the correct lube is supposed to be, but when I took it apart, it had some thick black gease in the bearings. So probably some moly type grease. Though there is an oil port on the center. I think, but I do not know, that through time the grease gets gradually thicker and requires some oil to be squirted in to thin it out?

I lightly greased the bearings with Shell Gadus S2 V100-2 which is designed for roller and plain bearings. It has an ISO 100 viscosity (which is around 30wt oil).
 
thestelster said:
thick black gease in the bearings
Click to expand...

It's also possible that it got black over time and usage and didn't start out that way. Turning black over time is pretty normal in high pressure applications and so is grease colour uniformity because the grease viscosity reduces a bit during usage.
 
So it turns out that the tiny cage bearing at the tail end of the live center is the problem.
Ordered a new center so now this one will go into the "THIS DOESN'T MAKE ME A HOARDER" bin.
 
Susquatch said:
It isn't replaceable?
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Probably but I also can't seem to get the little bugger out.
I can find no information on the size it should be or the manufacturer of the tailstock, SYD.
There is a larger cage bearing at the front followed by a thrust bearing. The smaller one is currently trapped near the end. I believe there should also be a small ball at the very end where the cap screws in that is missing as well.
New one is one the way.
 
Doggggboy said:
The smaller one is currently trapped near the end.
Click to expand...

Make a collet puller to get it out.

Post in thread 'Live center disassembly .' https://canadianhobbymetalworkers.com/threads/live-center-disassembly.4324/post-59266

Maybe you can also drill an Access for a shaft to push it out as also described a little later in the thread at the link above.

I'm particularly interested in this issue because I have a precision live center that I somehow managed to brinell a bearing in. I like the center very much so I'd like to fix it. In the meantime I ordered another one just like you did. But I don't like it nearly as much. I bought the old one a decade ago or so and I can't seem to find one just like it anyplace.
 
Fine.
It was raining today anyway.
So I drove the bearing out the tailstock end of the live center with a punch.
11mm OD by 7mm ID
Part is a drawn cage needle bearing HK0709
Readily available on Amazon for literally pennies, as in a 10 pack for 5 bucks.
I splurged and ordered one.
I'm sure it'll be top notch:D
 
Doggggboy said:
So I drove the bearing out the tailstock end of the live center with a punch.
Click to expand...

That's AWESOME! Good on you! Another perfectly good tool escapes the parts bin!

But, I need help understanding what you did. Your description could mean different things to me. I'm a bit dislexic.

Did you drive the bearing itself rearward toward the tailstock, or did you insert the punch from the tailstock end and drive the bearing itself forward toward the headstock? In other words, which end did the bearing itself exit from?
 
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