This set-screw coupler allows you to connect ¼” diameter shafting to ⅜” diameter shafting. Each end of the coupler has an M5 set-screw to secure the shaft in place. Set-screw couplers are excellent in low-clearance applications.
As an added feature, this coupler has a built-in shim at each end. This allows the coupler to run against a bearing without contacting the outside race.