# Spindle bearing



## Danny (Apr 26, 2018)

What is the consequence of putting the spindle bearing on opposite of the way it came off? = did not mark front and not sure if it is on properly, this is the front bearing.

Thanks in advance
Dan


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## RJSakowski (Apr 26, 2018)

It depends on the bearing type.  Angular contact bearings are meant to be used in pairs, opposing each other to take up axial play. They must be oriented correctly.  Tapered roller bearings, the same.  

A simple ball bearing should be able to be used in either orientation with the exception of possible seals.


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## Danny (Apr 26, 2018)

RJSakowski said:


> It depends on the bearing type.  Angular contact bearings are meant to be used in pairs, opposing each other to take up axial play. They must be oriented correctly.  Tapered roller bearings, the same.
> 
> A simple ball bearing should be able to be used in either orientation with the exception of possible seals.


I should have been more specific, the bearings are the brass sleeve type with a spreader slot in them


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## RJSakowski (Apr 26, 2018)

Aside from any lubrication grooves or holes, I don't think the orientation would matter.


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## Danny (Apr 26, 2018)

RJSakowski said:


> Aside from any lubrication grooves or holes, I don't think the orientation would matter.


I wouldn't thinks so either but everything I have read specifically says to make sure front stays front. Just wondering why.

Dan


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## RJSakowski (Apr 26, 2018)

Generally, If it isn't possible to distinguish front from back, I assume there is no difference.  What is the specific application? Your references may be talking about the front and back bearings rather than bearing orientation.


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## Danny (Apr 26, 2018)

The front and back bearings are different in length, I'm talking about bearing orientation = front bearing pointing in the same direction that it was pointing when I took it off the spindle. This is a SB heavy 10 head stock bearing that I'm talking about. I guess I didn't state the manufacture of the lathe that I was asking the question about. This particular bearing is ahead of the bull gear which has to be pressed off to get to the bearing, beyond the bearing is a shoulder and beyond that is the threads that the chuck screws onto


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## markba633csi (Apr 26, 2018)

Danny: If you are removing and replacing the original bearing then you want to put it back in it's original position.  Flipping it around "messes up its head"
so to speak, and the clearances will change. 
Try to match up the wear marks if you can.
Mark


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## Technical Ted (Apr 26, 2018)

When I worked on my SB13 spindle and bearings I found that both the bearings and the dovetail spreader were marked with an "F" for the front side. If a bearing is hand scraped in, I personally would definitely want to reinstall it in the correct orientation.

Ted


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## Tozguy (Apr 26, 2018)

As Mark mentioned, those bearings need to go back in to exactly where they were in all respects. Not only may they have been bored straight in situ when new but they have also worn in since. This makes them good only when they are back to the original position.


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## Danny (Apr 26, 2018)

Thanks for all the responses guy's that is the information that I wanted.

DanH


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## derf (Apr 27, 2018)

If you're in doubt, track the bearing with something that will make a witness mark, like a sharpie. Mark up the inside of the bearing and roll it around the spindle a few times and see how much contact you get. Hey....you got a 50-50 chance.


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