Accuracy: ?2″.
To inspect protractor, taper gage, index plate, index head and goniometer, can also be used to set angle.
Made of special alloy steel, hardness HRC64, high stability, wear resistance and easy combination.
Can be combined to any angle with interval 6 seconds after combination (6″, 12″, 18″, … , 360?).

3M 26138, PPS Series 2.0 Adapter, Type S42, 3/8 Female R-Angle, 19Thread BSP, 7100135930
3M 55700, Stikit Film Disc w/Tab 375L, 6 in x NH P150, 7100106618, 250 per case
3M 33443, Cubitron II File Belt, 36+, 1/2 in x 18 in (12.7 mm x 457.2 mm), 7100033184, 10 belts per carton, 5 cartons per case
Dynabrade 98270 1/2" Male Coupler
3M 26110, PPS Series 2.0 Adapter, Type S24, 1/4 Female, R-Angle 18
Thread NPS, Side Cup Mount, 7100135940 
