Recently got a lever type DTI, never used one before, only dial gauges. It is a Mitutoyo 513-205F 1) was under the impression the lever should rotate with gentle pressure. Only a light friction fit to the pointer mechanism.This doesnt rotate, and not so easy to get body in correct position for bores. Is there a trick to get it to move? 2) It has dovetails and a shaft for mounting on the back. The shaft does not unscrew or appear removable, yet also has dovetails on the back face. The dovetail would be more useful, if it does come out?