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 14593, Scotch-Brite Cut and Polish Disc, 3" x 1-1/4" x 1/4" A Medium, D5, 7000045941, Box of 10
Insize ISHB-B300, BARCOL HARDNESS TESTER, 6928640325489
3M 76783, Cubitron II Hookit Cloth Disc 784F, 120+ XF-weight, 5 in x NH, Die 500X, 7100222757
Dynabrade 78768 3" Dia. x 2" W x 1/4" Shank, Medium, NWN DynaBrite Wheel, 10/pack
3M 01326, PSA Cloth Disc 348D, P240 X-weight, 3 in x NH, Die 300V, 7000045069
3M 22393, Roloc Disc 361F, 36 YF-weight, TR, 3 in, Die R300V, 7000045093
3M 92250, Extra Large Single Angle Sanding Sponge 910PSA-12-CC, 2-7/8 in x 8 in x 1 in Fine, 7100101547 