Ideas for a line reamer

[Mutt]

Opinions/ideas on a reamer. It's a line reamer. .466 diameter. It needs to reach across 6". the bushings are only about 5/8" long, there is about 4" between the 2 bushings. I was thinking maybe a double shell reamer, but I googled it and didnt find anything.

 

[KyleG]

What's the unfinished diameter of the bushings? I had a good experience with RTS Cutting Tools recently. They ground a 4 step reamer (2 pilots, 2 cutting) to line ream some bushing pairs. The slightly tricky thing about your case is that both bushings are the same length.

You could just use a really long standard reamer, but it would be nice to have something bearing in the second bushing as you're cutting the first bushing so they end up coaxial. A hand reamer might have enough taper to do this for you, if you can find one long enough.

 

[benmychree]

There are adjustable hand reamers available with guide pilots and cone shaped guides that are able to accomplish tasks such as you describe.

 

[Toolmaker51]

Piloted and bushed reamers as benmychree suggestions offer, are the time tested solution.
I wonder how many cast frame electric motors were handled exactly that way; after line boring or in rebuild.

 

[KyleG]

There are adjustable hand reamers available with guide pilots and cone shaped guides that are able to accomplish tasks such as you describe.

Are you referring to something like this? https://www.icscuttingtools.com/catalog/page_194A.pdf

I haven't ever seen them before, but they look like just the ticket. Does friction hold the guide bushing in place, or do you have to hold/clamp it in the hole?

 

[Toolmaker51]

Yes. That illustration depicts what we are advising. They are close sliding fit, the bushing length minimizes axial play. It centers on hole, while reamer progresses. I grease the bushing and shaft a bit, that stickiness helps.