Stump Jumper / Flywheel 12 Splined Hub This hub will work in several different brands rotary cutters and can be made to fit in several more This is the hub that slides up on your output shaft that is welded to the blade carrier on your rotary cutter 3" across (76mm) 2-1/4" tall (58mm) Where the lip is that goes up into the blade carrier it is 2-7/16" (63mm) across lip height is 1/4" tall (6mm) 12 splined hub, valley to valley 1/5/8" or 42mm. The splines are tapered to fit on the tapered output shafts used by the majority of manufactures. We carry all sorts of rotary cutter parts as well as other farm equipment parts. Optional Stump Jumper Parts Available: HL418 - Blade Bolt Kit - Round Shoulder HL418N - Blade Bolt Kit - Square Sholder 75400 - 15 Splined Stump Jumper Hub 45300 - 12 Splined Hub