37.4 mm Shafts | McMaster-Carr

Create a compact linear and rotary motion system for applications requiring complex, fast movements, such as robotics. The grooves on the ball splines transmit rotary power as ball bearings move smoothly and precisely along their length, even at high speeds.

Ball splines are alloy steel for high strength and wear resistance. They're hardened on the outside for additional wear resistance while the center is soft enough to absorb stress from shifting loads. Those with a step-down end have a shoulder near the end to stop gears, sprockets, and bearings.

Bearings have a retaining ring groove, so they can be positioned in your system with a retaining ring (not included). Flanged bearings have a surface with mounting holes for attaching your load.

Ball Splines

Splined End × Step-Down End

Four Splines

				Spline			Step
Dia., mm	Dia. Tolerance, mm	Lg., mm	Lg. Tolerance, mm	Lg., mm	No. of	Root Dia., mm	Dia., mm	Dia. Tolerance, mm	Lg., mm	Surface Smoothness, microinch	Edge Type	Hardness Rating	Hardness	Heat Treatment		Each
Metric—52100 Alloy Steel
Splined End × Step-Down End
37.4	-0.025 to 0	550	-0.7874 to 0.7874	400	4	33.1	30	-0.021 to 0	150	16	Chamfered	Very Hard	Rockwell C60	Case Hardened	00000000	0000000

Flanged Bearings

					Material					Mounting Hole
For Spline Dia., mm	For No. of Splines	Overall Lg., mm	Flange OD, mm	OD, mm	Bearing	Ball	Dynamic Load Cap., lbs.	Max. Dynamic Torque, in.-lbs.	With Retaining Ring Grooves	No. of	Thread Size		Each
37.4	4	100	90	60	Steel	Steel	6,900	5,637	Yes	4	M8 × 1.25 mm	00000000	0000000