Standard style (SC) shaft collars use a hardened set screw to penetrate the shaft so as to achieve gripThis penetration yeilds light-duty benefits for applications like thrust collars, abor spacers, sprockets hubs, bearing holders, and shaft protectorsSC collars do not work well when th shaft is harder than set screw or when penetration marks on the shaft are not desirableBlack oxide coating will slightly increase friction and holding power in some applicationsFinish: Zinc Inside Diameter: 13/16 Inch Inside Diameter Maximum: 0.8165 Inch Inside Diameter Minimum: 0.8135 Inch Item: Shaft Collar Material: Low Carbon Steel Measurement: Inch Origin: Imported Outside Diameter: 1-1/2 Inch Outside Diameter Maximum: 1.3205 Inch Outside Diameter Minimum: 1.3045 Inch Set Screw Size: 5/16-18 Style: Solid Set Thickness: 9/16 Inch Thickness Maximum: 0.5675 Inch Thickness Minimum: 0.5575 Inch Type: Round Bore