Rebushing an already rebushed pivot hole

Dan A

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Dec 31, 2020
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Rebushing an already rebushed pivot hole would seem to be a fairly common clock repair procedure but I haven't found anything written up about how to do it. The bushing I need to replace is size L17, which uses a size III reamer, so I would have expected there would be some bushings with the same I.D. and the next bigger sized reamer IV. None of the bushing charts I have found indicate such a bushing exists. Do I have to lathe my own? How would you re-rebush this pivot hole?

Thanks for sharing whatever experience you may have had with this challenge.
 

Vernon

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Dec 9, 2006
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If I'm understanding your question, you won't need to ream the plate for a different od. Support the plate and push the old bush out through the back of the plate then install the new bush with the same od from the back.

Vernon
 
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bruce linde

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i do this all the time.... if you're replacing a size III bushing you might want to put a hint of loctite around the new bushing to insure that it stays in place. i have also, on occasion, been able to use a IV with a III bushed into it....

of course, there's also the option of turning the exact size you need... got lathe? :)
 

Willie X

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Feb 9, 2008
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Dan,

I'm not exactly sure what the problem is.

You state the bushing in question is for a #3 reamer. I'm guessing the available #III bushings do not have a useable size pivot hole?? You wouldn't normally go to a larger #4 bushing, if you are replacing like for like ...

The only exception I can think of, is for a
re-pivot, where the new pivot is a lot bigger than the old worn out pivot??

Willie X
 

bkerr

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One thing to look out for especially if you have older or used reamers for you KWM system is a dull or worn reamer. A worn reamer will produce a slightly over sized hole. I have had this happen and at first could not figure out why. I asked a fellow clock maker and he filled me in on the issue. I agree with the Loctite mentioned above. Done right you will never see it.
 

R. Croswell

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Rebushing an already rebushed pivot hole would seem to be a fairly common clock repair procedure but I haven't found anything written up about how to do it. The bushing I need to replace is size L17, which uses a size III reamer, so I would have expected there would be some bushings with the same I.D. and the next bigger sized reamer IV. None of the bushing charts I have found indicate such a bushing exists. Do I have to lathe my own? How would you re-rebush this pivot hole?

Thanks for sharing whatever experience you may have had with this challenge.
If the previous bushing was installed properly, which is often questionable, you should be able to press out the old and in with the new. There should be no need to ream for or install a larger OD bushing. However, if the previous bushing was installed "by hand" using a tapered broach, or a hand-held reamer and the bushing expanded by peening to tighten it in an oversized hole or a hole without parallel sides, you may find that the new standard size bushing will be too loose in that old hole. One option may be to use a Bergeon bushing and reamer which will usually have a larger OD for the same size pivot hole. Before removing the old bushing, it is a good idea to check the depthing of the wheel and pinion. A lot of amateurs (and some who consider themselves something else) simply ream the hole and drive in a bushing and hope it is centered "close enough". If the first bushing was not properly centered the only option may be a larger, properly centered, bushing.

.... if you're replacing a size III bushing you might want to put a hint of loctite around the new bushing to insure that it stays in place.
Agree.

RC
 
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shutterbug

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If the inner hole is the issue, you can use a smaller ID and ream it larger. If you have machinist gauge pins, you could use those for a more perfect hole. Just cut an angled edge on one end so it acts like a drill.
 

Dan A

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Wonderful responses. Thank you!

I was lucky on this repair, the old bushing was successfully pushed out and the new bushing fits quite nicely. I was way overthinking the re-rebushing challenge, thanks for setting me straight.

Dan
 

POWERSTROKE

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Jan 11, 2011
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If you at stalking about the I.d. Nir being the correct size, or something you cannot get. Use a size smaller and broach it to the correct size. Punch the old one out and put the new one in.
 

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