PowerTorq™ inner races are made of high quality 4150 alloy steel, induction hardened to Rc 56-60. PowerTorq™ outer races are made of hardened steel with ball tracks heat treated to Rc 56-60. PowerTorq™ ball spline inner and outer races are protected with a black oxide finish.
PowerTorq™ Ball Splines are straight within .010 in/ft when shipped from the factory, and do not exceed .030 inch in any 6 foot section. Twist is limited to .015 in/ft at the ball circle diameter.