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: 11/16 Inch Inside Diameter Maximum: 0.6915 Inch Inside Diameter Minimum: 0.6885 Inch Item: Shaft Collar Material: Low Carbon Steel Measurement: Inch Origin: Imported Outside Diameter: 1-1/4 Inch Outside Diameter Maximum: 1.2580 Inch Outside Diameter Minimum: 1.2420 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