Range Spindle Square with 0.001 in. Grads The Starrett 649 Series Spindle Square offers accuracy, convenience and significant time saving with the common shop task of tramming the head of a vertical milling machine. This must be done regularly to ensure squarness and perpendicularity between the spindle and work surface. The spindle square is easier to use and more precise than the traditional method of tramming with a dial test indicator. FeaturesFully assembled with two AGD Group 2 dial indicatorsPatented designSolid steel body construction with durable black oxide finishGround gaging surfaceApproximately 4 lbs with custom case3/8" inch shank diameter4" between contact pointsApproximately 6-3/4" wide and 5-1/2" from the top of shank to the end of the contact pointsSpecificationsSize: 0.250 in.Type: Spindle SquareRange: 0.250"Graduation: 0.001"Dial Reading: 0 - 50 - 0