On Sun, 09 Dec 2007 13:26:57 -0800, Grant Erwin wrote:

I have this old machine I'm working on in my spare time. When I say old,
it's really old, probably pre-1920. It has two shafts which had gears
fixed to them by pinning. The shafts were drilled and the gears were
drilled but the holes didn't line up so they just took thin pin stock
and banged it in so it bent but jammed in there "good enough".

Now I took it all apart and don't want to replicate the bent pin trick.

I'm thinking of temporarily fixing the gear to the shaft somehow,
setting it up in the mill, and drilling straight through with a 1/4"
drill and then just push through a 1/4" roll pin. I can't really figure
out how to fix the gear onto the shaft temporarily, though. Ideas?

PS I'm open to other solutions, but I think a set screw might slip ..

Grant

Before you "repair" that "screwup", you may want to make sure that the
machine wasn't designed correctly in the first place, then made a victim
of poor maintenance.

Not knowing what the rest of the story is I can't say, but are you sure
that the shaft, gears and pins weren't right from the factory, then made
wrong by some major maintenance that put some _other_ pieces in the wrong
spots? Could the shaft have been put in backwards, or it's locating
hardware put in wrong, or the shafts that it runs against done wrong,
etc.?

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html