I am designing some parts that must fit the drive pulley hub tightly.  my question is, since I've never done this before, involves measuring the existing pulley.  can I assume that measurements are typically even numbers, and that a hole diameter isn't 49.12mm for instance?  I can fit drill bits thru the bolt holes and drive pins to get accurate measurements there.  I discovered that, indeed, the bolt holes aren't at 90 degrees, but appear to be at 85 and 180 degrees, which means the reluctor wheel only fits one way.  I located the holes by measuring the distance between adjacent holes.  again, can I assume an offset of an even 5 degrees?  I am using some electronic calipers from harbor freight.  do you find these accurate enough?      kevin

Kevin,

Th Rotary is indeed built in Metric, It amazes me how some can measure in inches, but when converted back to metric to a couple of decimel places. Something lost in the conversion I'm sure - so stay with Metric.

However, having said that there are many instances where mm are to 2 decimel places  -  that goes for degrees as well, sadly. I guess nothing can be built/planned that exactly.

The e-shaft is in full mm ( for the most part) but ground for tolerances, so I asume the pulleys are drilled in mm as well, although haven't checked.

Hope that helps, and let us know what you find.

George (down under)