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 81283, Scotch-Weld High Strength Retaining Compound RT38, Green, 50 mL Bottle, 7010310185, 10/case
3M 45020, Diamond Grade DG3 Reflective Digital Sheeting 4081UDS, Fluorescent Yellow, 30 in x 50 yd, 1 Roll/Case, 7100282390
3M 08749, High Bond Rearview Mirror Adhesive, 0.02 fl oz, 7010364470, 12 per case
3M 77512, Cloth Belt 777F, 60 YF-weight, 1 in x 42 in, Film-lok, Single-flex, 7010307736, 200 per case
Standard Abrasives 840138,Quick Change Surface Conditioning GP Disc, Medium, TSM, 1 in, 7000121649, 50 per case 