- Nov 26, 2018
This is my own copy of the suburban tool magnetic cylinder square. The base is made from a 2.5" diameter one inch thick hardened 1045 steel having a thou under bored hole and recess . The shaft is a 3/4" piece of drill rod with a 1/2" hole for weight reduction that has been pressed into the base. The recess bored out of the bottom of the base where four magnets are placed with an aluminum ring and the void is filed with epoxy. Just after assembly there was little over a thou of error in squareness, this was measured by test indecator from base to tip the revolved four time in 90deg increments. Corections were made by lapping the base in and repeating the measurements. It now holds an error of less than .0001" referanced both to itsself and to an angle plate that was measured optically.