Turning down a bushing

[plehrke]

I need to make a bushing to use to attach my alternator to the new brackets I am installing. Bracket accepts a AN5 (5/16") bolt and hole in alternator is 11mm (.45"). I have a 0.5" OD bronze bushing I want to reduce to the 0.45". Any tips on turning down the OD without using a lathe?

[BillL]

How long is the bushing? If short, grind down the head of a bolt and a nut then clamp it and use a drill press (OK, a drill works too), file, and sand paper. File across it in a normal manner, don't just hold it against it. Check with dial caliper and when within a few thou, switch to 80 - or 180 grit hardware cloth. Wrap around and move like an old shoe polish action.

[az_gila]

Getting a bushing down to 0.025 thickness will be tricky.


Bad math... it will be about 0.060 thick, still tricky...


How about simply drilling out the hole in the alternator?

[DaleB]

McMaster-Carr will happily sell you a sleeve bushing, 8mm ID / 11mm OD.

[sblack]

If you have a solid bronze bushing it will be machinable. If it is scintered bronze (oilite) it will disintegrate because it is basically compressed powder. If it is a sleeve you want just to take up an empty space and not something that needs to provide a bearing surface for a turning shaft then make it out of mild steel. There must be an EAAer in your area with a lathe. It is a 2 min job.

[Bob Kuykendall]

Originally Posted by sblack

If you have a solid bronze bushing it will be machinable. If it is scintered bronze (oilite) it will disintegrate because it is basically compressed powder...

I lathe turn Oillite sintered bronze bushings pretty much every week, and they turn down just fine.

Thanks, Bob K.

[Jesse]

Originally Posted by plehrke

I need to make a bushing to use to attach my alternator to the new brackets I am installing. Bracket accepts a AN5 (5/16") bolt and hole in alternator is 11mm (.45"). I have a 0.5" OD bronze bushing I want to reduce to the 0.45". Any tips on turning down the OD without using a lathe?

Why not just drill out the bracket to accept the size bolt that fits the alternator. A grade 8 metric bolt should work just fine.

[DaAV8R]

If I didn't have a lathe I would try getting a bushing that was 11mm OD with a small enough ID to drill or ream the ID to correct size. You might get away with a 11mm OD and a 8mm ID. Our local hardware store has a surprisingly good assortment of odd bushings.

[plehrke]

Originally Posted by BillL

How long is the bushing? If short, grind down the head of a bolt and a nut then clamp it and use a drill press (OK, a drill works too), file, and sand paper. File across it in a normal manner, don't just hold it against it. Check with dial caliper and when within a few thou, switch to 80 - or 180 grit hardware cloth. Wrap around and move like an old shoe polish action.

Thanks all for the suggestions. All good.
BillL, This was my first thought as well. It worked great. Clamped bushing with a long bolt and nut, chucked bolt in air drill, duct taped drill trigger, used file and sandpaper. In a few minutes took of 0.05" and ready to go.

Originally Posted by sblack

There must be an EAAer in your area with a lathe. It is a 2 min job.

I have 3 lathes within a few hangers of mine. Just like doing it myself and got it done before others showed up at the airport. Two guys said they would have done it for me but it was done and installed before either of them were awake. Both offered to give me a check ride on their lathe so I can do-it-myself next time.

Originally Posted by Jesse

Why not just drill out the bracket to accept the size bolt that fits the alternator. A grade 8 metric bolt should work just fine.

It goes through the tensioning bracket which is a long slot and would have had to open the entire 1.5" long slot. Plus Could not open the slot to 0.45" for lack of edge distance.

Originally Posted by DaAV8R

Our local hardware store has a surprisingly good assortment of odd bushings.

Went to two of our best local hardware store (not big box stores) that usually never let me down with theses sort of things. Neither had anything close. Could have made the part in 1/10 the time I spent trying to find something closer.

[sblack]

Originally Posted by Bob Kuykendall

I lathe turn Oillite sintered bronze bushings pretty much every week, and they turn down just fine.

Thanks, Bob K.

Really? Ok, then u know something I don't