In order to be able to have micrometer accuracy on my small 8" drill press as opposed to the terribly inaccurate little ruler that usually accompanies these machines, I created a micrometer dial to control the depth of drilling to within a thousand's of an inch.
The spindle was removed and the end portion that fits within the drive pulley was drilled and tapped to 1/4-20 for about 1". A length of threaded rod to match was screwed to the end of the spindle after re-installing it and secured with "Locktite".
The dial was made entirely on a Taig microlathe and engraved with a side mounted tool and indexing plate to cut 50 divisions.
Cuts are made by advancing the carriage by hand; the length of the cuts are controlled with the built in carriage depth rod on the Taig.
The procedure is shown on the engraving page.
Click on the picture below to go directly there!
To use the micrometer depth stop when wishing to drill to an exact depth, I bring the drill point so it is touching the work. I then screw the dial down toward the machined surface of the drive pulley and tighten it against it. That is the 'zero" point. I then counter rotate the dial whatever the amount I need to drill. For instance, if I need a ½" deep hole, I will need to counter rotate the dial a total of 10 turn. The dial has 50 marks equally on thousands each so 10 x 50 thou = .050" as the hole is drilled the dial rotates with the spindle synchronous with the pulley and the rod so when the dial is smack against the rotating pulley, I have reached the ½" depth. It is as simple as it sounds. Give it a try!!