Brian McKenzie wrote:

Guys,
Reducing Rivarossi wheel flanges is fraught with danger and some of the
ideas advanced will certainly lead to their destruction - as it did for me
in my early hobby days.
Unless individual wheels can be adequately supported by shaped pegs clamped
through the spokes, to the end of a round bar in a lathe, they may not
survive the forces exerted by a turning tool.

I see I should post a close-up pic of an AHM wheel set nested in a three jaw mill chuck. It's a very small amount of material in the cross section that gets removed.

A similar set-up works well in conjunction with a Dremel type tool fitted
with a suitable grinding wheel. Ideally, the grinding wheel tool will be
under some sort of steady in-feed control and the wheel should turn
relatively slowly, say 150-200 revs, which is possibly slower than some
small lathes provide.

There are pre-made RP-25 profile cutters available that would cut both wheel taper and flange in one bite from a blank, or re-shape a really poor wheel to proper profile.

The main secret is to securely mount the wheel or wheel set so that it can be cut as a rigid part. In most cases, you are only removing a very few thousandth's of metal. The closer you work to the mill chuck, the more rigid the cut will be. If you can get the part you need to cut near there, you don't need much of an elaborate holding fixture. I find that a 3 inch lathe chuck works well on wheels under two inches real diameter if you nest the outside of the wheel into the mount of the chuck and wind up cutting first from the back of the wheel and then trimming the contour of the snipped flange inline with the flange itself.

It's the same way all truck wheels, motor heads, and contoured rollers are manufactured in the machine shop at Da Job; just nest securely into trimmed jaws and cut.

Look at:
http://groups.yahoo.com/group/HOsteam/files/Grinder%20Workhead.jpg
in the Group Files, to see a device used for applying a slight taper to axle
ends, or for truing wheels. A finer grit wheel than the one in the photo is
used. As axles/wheels rotate about their own axis it is easy to make minor
adjustments/corrections. The electric motor is from an old record player
and the drive belt is sliced from mountain bike tube.

A slick solution.

--
regards,
Mike Bauers
Milwaukee, Wi, USA