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Taper roller bearing wear

Harri89

Cast Iron
Joined
Nov 21, 2016
I am wondering if i should change these or not, they feel "ok"
The contact area is matt, lost its shine.

Can you help me by looking the pictures, thank you! :)

IMG_20191103_121603.jpgIMG_20191103_121611.jpgIMG_20191103_121641.jpg
 
Cincinnati vertical manual Milling machine feed motor drive gear bearings, theres motor, idlers and then this with bevel gear in one end.
 
Cincinnati vertical manual Milling machine feed motor drive gear bearings, theres motor, idlers and then this with bevel gear in one end.

Just some normal wear then. But there may be some very fine dirt in the grease. I'd clean and regrease, and carry on. I usually use Mobil 1 synthetic grease for such things.
 
I look at it like this and have to ask, or ask yourself. Why did you take it apart in the first place. Noisy? Jerky? How old are you and how long are you planning to use this machine? Are you rebuilding and repainting to sell?

If flipping it I'd leave them. I do see a couple nicks in the one bearing but they're not all that terrible. If keeping it and foresee a long life of use, I'd replace them. You've gone through the trouble of taking the whole thing apart, take advantage of that work and renew the races and bearings. That is if the new bearings are easily reachable in your budget. It's been a long time since I've bought a tapered roller bearing. I don't recall them being out of reach in price compared to other bearings.

If you don't already own the proper tools (pullers/press/etc) to renew the races and bearings, just put them back, as the cost of the tools on top of the bearing cost could potentially slant my thoughts of replacement in this instance. That is with the bearings being in not too completely terrible shape, and the idea that I bet their rotational speed during use is pretty low compared to say a trailer or automotive wheel bearing application.

One last thing... careful not to over-pack the grease.

Dave
 
I am 30 years old and i wish i wont sell this beauty never :)
It was noisy when feed motor was running, i took it apart and didnt found any clear reason for the sound. Now i need to check the bevel gear contact pattern.

These are in oil bath.


I quoted new bearings, since i live in metric country, these bearings with flanged outer race... 100euro each bearing...
 
Tapered rollers that look no worse than that I clean with solvent, dry and apply light oil.Apply hand pressure and rotate.If they feel smooth and and the rollers all roll then there is nothing wrong.Re use and check preload if used.
 
I am wondering if i should change these or not, they feel "ok"
The contact area is matt, lost its shine.

Can you help me by looking the pictures, thank you! :)

View attachment 269085View attachment 269086View attachment 269087

Bearings generally wear on the roller ends where they rub against the shoulder that restrains them. The rollers are also very lightly crowned and will also wear.

Take a look at the roller ends. If they are worn to the center recess they are shot and should be replaced.

Also take a look at the inner race. It works harder than the outer race and will be the race that will show the first signs of distress.

If the inner race looks like the outer and the rollers are not worn I would use them.

Don't preload used taper bearings to new bearings preload specs. Tapered roller bearings are designed to wear slightly from the initial preload and run happily ever after at zero preload. Another way to look at it is that taper bearings need a slight dimensional compression when new and will wear to a zero compression. Since we cannot measure or set a dimentional compression we do the next best thing and approximate it using a rolling torque.
 
Its not that big job to get it done when needed. Drain oil from knee, Motor off, 4 bolts, Casing of the knee 9 bolts and the shaft with the bearings 4 bolts.
 








 
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