The following information is provided by the manufacturer. We have paraphrased it to some extent. The original instructions are included with new bore gage purchases. Information on new Dorsey bore gages can be found on page 71.
Measuring head fastening screw (lock screw)
The fastening screw (called "Lock Screw" by the manufacturer) is set at the factory and does not need to be adjusted unless the user needs to rotate the dial indicator so that it faces sideways. Naturally, if the measuring head and the indicator have been taken apart for repair or replacement, then these instructions apply as well.
- Loosen the lock screw
- Rotate the indicator into the desired position
- Assemble the two parts (measuring head and dial indicator) until there is contact causing the hand to move
- Back off slightly so that there is a very small gap between the two
- Tighten the screw being careful you don't use so much force that you strip the threads
- Check for travel by pressing the gaging plunger with your fingers (there should be about .030" overall travel on the dial)