Splitting Bearing To Avoid Equipment Disassembly

[bugnut]

I have a machine tool with a column of about a foot in diameter. It requires an upper and lower tapered roller bearing and race. The pivot only rotates in and out 180 degrees in about 15 seconds and 3 times an hour. Load is less than 2 tons. Now the question-existing bearings are 20yrs old and looking at race surfaces need replaces-I want to edm 4 sets to make two perfectly fitting sets so I do not have to disassemble the machine tool and can replace the bearings. On one machine tool I see this has already been done.
Questions is/are-What are the pitfalls of doing this? Do I need to destroy 4 to make 2 or is leaving a small .006 gap from the edm wire okay? Thoughts/Comments.....

 

[dvd]

Have you thought about Cooper or Kraft split bearings?

 

[dimjim]

Call the bearing manufacturer and see if they have any comments. Segmented bearings will not take the loads
that full bearing can withstand. I do not think two
bearing sections from different bearings will have the
same geometry. Close is not good enough.

 

[unclesyd]

I have to concur with the above posts you should have to get
a bearing from a manufacturer.
We got a lot of our split bearings from FAG.

http://www.fag.com/content.fag.de/e...g=split+bearings&searchID=1&searchOption=/en&

a bearing from a manufacturer.

 

[ischgl99]

I have never seen a split tapered roller bearing. FAG makes the spilt spherical and Cooper makes the split cylindrical bearing.

If you EDM the bearing, how do you plan on securing the two halves together? Split bearings are made with space for screws to reassemble the bearings, if you cut these bearings, you might not have any room to do this. Another problem with doing this yourself, the two halves might not match up well enough to provide a good running surface. Since this is low speed, a small gap between the two halves might not be a problem, but your life probably will be reduced.

Since the existing bearings lasted 20 years, I would bite the bullet now and do it right and get another 20 years out of the bearings instead of taking a chance on splitting a bearing that was not meant for splitting.

 

[rob768]

Why not do a re-design and check if a split bearing would function without reserve. Ask your bearing supplier if you have second thoughts. Split bearing function well in many installation, so perhaps also in yours.

 

[Tmoose]

Do machining operations take place during the 180 degree swing? Split bearings generally have measurable vibration at roller pass frequency as the rollers jump the race gaps. For some applications it does not matter (other than getting vibration analysts all twitterpated), but If you are doing fine finishing or grinding I'd expect surface finish issues to result.

 

[electricpete]

twitterpated.... I haven't heard that one in awhile.

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[Tmoose]

I think Thumper said Bambi was twitterpated over a young lady deer. Probably Not really how Vibration Analysts feel about scary bearing vibrations, but I like to use it anyhow.