Outside Diameter Up to 1 inch +0.002-0.000 1-2 inches +0.003-0.000 2-4 inches +0.004-0.000 4-7 inches +0.005-0.000 7-12 inches +0.006-0.000 12-20 inches +0.007-0.000 20 and over +0.008 -0.000 Outside Diameter/ Metric Timing PulleysT2.5.T5, T10,AT5,AT10 +0.000 -0.003 Bore Up to 1 inch +0.001 -0.000 1-2 inches +0.0015-0.000 2-3 inches +0,002-0.000 3 and over +0.0025-0.000 Keyway Width ( w ) Up through 1/2" +0.002 -0.000 Over 1/2" to and including 1" +0.003-0.000 Over 1" +0,004-0.000 Keyway Depth ( t ) All Sizes +0.015 -0.000 Overall Length +0.015 -0.015 Flange O.D. +0.015-0.015 Belt Width +0.015-0.015 Face Width +0.015-0.015 Hub Diameter +0.015-0.015 Radial Runout (TIR) Up to 8 inches in O.D. Add for each inch over 8" O.D. 0.005 0.0005 Axial Runout (TIR) O.D. 1 inch and under Add for each inch over 1" O.D. 0.001 0.001 Helix Angle (TIR) Grooves should be parallel to the axis of the bore within 0.001 inch per inch of width. Taper Maximum permissable taper on outside diameter is 0.001 inch per inch of face width but must not exceed the O.D. tolerance.