Scag Cast-Iron Blade Spindles


Toughest, Best Built Spindle. Period.

Cutter blade drive spindles are a crucial component to mower performance. The average blade spindle rotates over 1.8 MILLION times in eight hours of cutting . That's 9 million times per week! Can you afford to have anything but the BEST blade drive spindles turning your cutter blades? Absolutely not!

Scag cast-iron spindle housings* are cast in Wisconsin, and precision machined at Scag with state of the art machining centers to ensure a perfect fit for the tapered roller bearings. Every Scag cast-iron spindle is assembled, greased and torqued by hand at the Scag factory.

This is the best performing, most reliable spindle in the commercial industry...hands down. We have been using this same rock-solid design for many years and proudly stand behind them with a 3-year limited warranty.

Scag Approved Spindle Greases:

  • Mobilgrease XHP™ 222
  • Exxon Mobil Ronex MP
  • Exxon Mobil Unirex EP2

Scag Cast-Iron Blade Spindles

Cast-Iron Spindle Details 

  • A call outBearings - Scag spindles utilize a matched set of tapered roller bearings. Tapered roller bearings have 50% more load capacity than ball bearings. The taper angles allow the bearing to handle a combination of radial and thrust loads, unlike a ball bearing.
  • A call outHousing - Cast iron spindle housing. Increased shock load strength over aluminum housings. Super strong to take the everyday abuses of mowing. In 2004, Scag spindle housings were upgraded to an even thicker mounting flange, increasing strength by 163%!
  • A call outHardened Spindle shaft 1-1/8" diameter. Extra large diameter, hardened spindle shaft provides superior strength. Key groove is cut into shaft for solid pulley mounting.
  • A call outGrease fitting. Top-mounted for quick and easy greasing. No need to crawl under the cutter deck.
  • A call outGrease relief valve . Special relief poppet valve ensures that "over-greasing" and damaging a seal is impossible, even with powered grease guns. The valve is spring loaded to prevent debris from entering the housing, unlike "weep holes".
  • A call outBlade bolt mounting hole. Cutter blade retaining bolt travels through the center of the shaft. Under extreme impact, only the bolt may need to be replaced, not the entire spindle assembly. The thru-bolt design also allows you to change blades without altering the proper preload (150 ft. lbs.) on the tapered roller bearings.
  • *The Freedom Z, Freedom Z Pro, Liberty Z, SWZT and SFW walk-behind use a sealed, aluminum spindle.