Quote:
Originally posted by Kevin A
A rotabroach is a tool the size of a pencil that you pound through the gear, and its teeth create a keyway.
It cannot be done with a bansaw or any power tool. You either gotta get a broach and do it right, or not key it.
One can be seen here: http://www.mscdirect.com/IWCatProduc...duct_Id=179005 :: SNIP ::
|
Not quite. That's a keyway broach. A Rotabroach (tm) cuts a circular hole. Think very aggressive hole saw that can blow through 1/4" thick aluminum in 30 seconds flat. Hougen Manufacturing makes them, see link:
http://www.hougen.com/cutters/cutters_index.html
And, to cut the bearing pockets on a manual mill, cut using either a rotabroach or a drill bit slightly undersize (up to about 0.030"), then ream to final size. If you ream about 0.0005" or 0.001" under the bearing's OD you'd get a tight press fit. Make sure that the bearing case won't be compressed too much though. the bearing vendor should be able to tell you what is a good press fit for a bearing. a little bit of time invested here will save you a LOT of gearbox troubles.
and don't underestimate the side loads that helical gears can generate. That crippled 824's drive train last year.
-=- Terence