Re: [CAD_CAM_EDM_DRO] Timing Belts and Pulleys

Dave Pope wrote:

>If they have been hobbed, or done on a gear gear generator of any type, they will (should) have used the pilot bore as the mandrel datum.
>If the cutter doesn't "crown" the tooth crests, then the outside could be "out". The root dia. and general profile should always be true to the pilot.
>
>

Believe me, none of these are hobbed or cut on a gear generator. The
steel pulleys are
sintered from powder in a mold, and are usually the worst. The flanges
are friction
stir welded on later. The aluminum pulleys are horizontal milled in
foot-long chunks
and sliced up and then the hub and bore are machined. The cheapest way
if you need
a bunch is to buy the raw, foot-long pulley stock and machine the hub as
you prefer.
If I was going to make commercial retrofit kits, that's what I'd do, as
I have to machine off
the hubs anyway, when mounting a pulley on the machine's leadscrews.

Jon