Jims Engine Sprocket Shaft For Harley Big Twin Features: Pins and shafts are machined from super-tough, aircraft-rated Durabar 60 steel and bearing surfaces are ground to a 16 micron finish Deep heat-treating provides 60-63 Rockwell hardness and CNC machined tapers guarantee concentricity within .0003 3-hole crank pin design distributes oil equally to both rod races Annealed threads on shafts allow torquing up to 100 ft lbs over the OEM specifications Made in the USA