It sounds to me as if it would be as easy to make a complete new brake
disk. You would only have to cut one thread.

Dan


jtaylor wrote:
I have a bicycle brake disk that I wish to mount on a (bicycle) hub.
The
disk is RH threaded and is meant to mount on the left side of the
hub, so
when the brake is applied it screws down onto a shoulder on the hub.
My
application means I need to mount this disk on the right side.

So what I think I'll do is make a shouldered collar threaded RH on
the
outside, and LH on the inside, and cut LH threads on the hub. The
disk will
run up to the shoulder on the collar and the collar will run down to
the
shoulder on the hub.

How thin can I make the collar? - there's a limit to how far I can
reduce
the hub diameter. The disk is threaded 1.375 x 24TPI; I'll probably
make
the collar from either brass or mild steel; and the hub is some kind
of
aluminium alloy.