On Wed, 28 Jul 2010 10:29:26 -0400, Brian Lawson wrote:
On Wed, 28 Jul 2010 08:20:15 -0500, Ignoramus6705 wrote:
On 2010-07-28, Lloyd E. Sponenburgh wrote:
Ignoramus8984 wrote:
I need to copy a sprocket from an old motorcycle for a friend of
mine. It has a conical hub.

My first two questions would be: "Is the hub conical simply as a
casting/forging expediency?", and (if it's tapered on the i.d.) "could
I cut that with a tapered reamer instead of milling the hole?"

No, it is tapered so that the sprocket would lock on the hub.

It is from some old Indian motorcycle. I am not a motorcycle guy and
have no knowledge or interest in them. But my friend does. This is
perhaps a 90 year old sprocket that needs to be reproduced. I would
guess that the angle on it is not standard.

In a machine/tool shop, they would probably do the "cone" as you have
done so far, leaving a few thou for finish, then on a Deckel SO (or
similar) would make a tapered carbide cutter, possibly just grind a "D"
type (or even 2 or 4 flutes) to the angle required and then use that
cutter and do the finish circular interpolation using it to give a
"finish" surface. [or] grinding stone/wheel cut to the correct angle
....

You could use a straight endmill, with the hub mounted on a rotary
table mounted on a sine plate set to the half angle.

--
jiw