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May 8th, 2022
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The problem is common, I think, and it can be shown on the drawing below

[Linked Image from i.imgur.com]

Two bushes precisely machined and pressed into the girder fork are misaligned. I can insert the pin into one of these bushes, but not into both of them. Of course I can use an expandable reamer to oversize the holes in bushes, but then fitting is poor and it's a short-life solution.
The reason of the problem is misalignment of holes in the fork.
The proper solution is to ream these bushes already pressed in. It must be done by special reamer, with piloting extension. I can't find such reamer in 1/2" diameter. Do you know where I can find it?
The second problem is that even if bushes are aligned there is no guarantee that both upper and lower pins are parallel.

Last edited by 3TandB24; 08/04/21 8:22 am.
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Or what you can do is make an internal pilot to hold both bushes and press them in at the same time. Alternatively, two pilots, one with both ends fitting the bush I.D., the other with one end fitting the bush I.D. and the other fitting the girder I.D.
If the forks holes are misaligned maybe those holes should be reamed in line. Set the forks on a mill and bore the two on one side then mount the fork on pins to hold it square to the first holes and do the other side.
There are long chucking reamers available, 12" long in plus and minus sizes. The pilot on reamers is usually short.
You could make a bushing for the shank to fit the near end. I think you would want it fairly narrow so the reamer is not aligned with the near bush, just centered with the end.

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What sort of clearances are you trying to achieve? Girder forks were not really precision made items. I thought I needed to replace the bushes on some Webb forks i have but a friend who was familiar with girder forks said just run them as they are. Trying to apply aerospace standards to old equipment can cause a lot of unwanted grief. As an aside; a i/2' piloted reamer should not be hard to source but a good one will cost.


Laurence Luce

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