The AAMCO 7" shaper has a 'feature' I don't understand. Maybe one (or
more) of you guys has an answer.

All the machine tool feed collars I have used (not really all that
many) have been graduated in some even numbered manner. Fifty marks,
sixty marks, two hundred, etc.

The graduated collar on the tool slide of this unit is different.

There is the usual '0' then the fifth mark is '5', then '10', etc.
This goes to the '60' mark.
Then there is one tick mark (two spaces) and then the orig. '0'

This actually _does_ result in a measured 62thou. advance per rev.

Nothing major, but I sure do have to keep it in mind when feeding more
than one turn.

Anyone ever seen something like this elsewhere?

Any one have a reason as to why this feed and calibration?
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