If you need an 8110-3 approval for a 337, send me a PM.
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Bushing the fitting was my suggestion to the Cub Crafters engineers but several months later they chose the other route. Seen Super Cubs run through trees and the fitting faired well but not the fork.
Given the amount of material around the hole in the fitting, there wouldn't be a problem. Using a bushing actually increases the bearing area on the fitting. The forks on the other hand don't have quite as much edge distance (but they are a little thicker, and in double shear).
I’m going to bring this thread back. Looks like I’m facing this on both forward struts on my Pacer. Is the bushing still the leading idea for repair? Is the offer of an 8110-3 still available? I need to run this by my IA if it’s doable on the paperwork side, or I need to find a shop to get it done (Steve?)
Jim
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Her is my proposed fix.
Attachment 20172
Attachment 20173
ID for the hole should be .372/.374, not .375. Make the bushings first, and ream the holes .0008 undersized for an interference fit. Chill the bushings in dry ice, and heat the fittings. Drop the bushings in and let the temperatures stabilize, then ream the hole to the .372/.374 size. Yes, I could do an 8110-3 so your IA has approved data for the 337. PM me for what is needed.
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From the Piper drawing.
Attachment 20174
My bad, not sure where I got the .372/.374 from. Correct would be .374/.376.
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You will want to match the bushing to an available reamer. Reamers are readably available in that size range in 0.4375 and 0.4370. Assuming you are using 7/16 OD 4130 tube, there will be a tolerance to the OD more then .0005 so you may not get a good fit. To match the reamer and the OD of the tube, you will need to machine the bushing down from 1/2" OD tube. 4130 is available in 1/2 OD .095 wall with an ID of 0.310 nominal. That would give you enough material to ream to .375. I got a sample of 7/16 tube and it turned out to be almost a prefect OD (about 0.0001 under). So a .437 reamer gave me a .0004 interference fit. That saved a bit of machine work. Your mileage may very.