China Freewheel One Way Clutch Manufactures DC7221b, Freewheel, Freewheel Clutch

Type DC is a sprag type freewheel cage without inner or outer races. It must be installed in a designproviding races, bearing support for axial and radial loads, lubrication and sealing. The DC type version-N accepts all types of lubricants currently used in the power transmission equipement.
The sprag space tolerance must not be exceeded. Inner and outer races must both have a minimum plain width "e", without any recess, to ensure the freewheel functions correctly as shown on following pages.

Alternatively, races can be made in case hardened steel shafts, or housings, to the specification below. Surface hardness of the finished part should be HRC 60 to 62, for a depth of 0,6 mm minimum.
Core hardness to be HRC35 to 45. Surface roughness not to exceed 22CLA. Maximum taper between races: 0,007 mm for 25 mm width.