Our 608 Bearing to NEMA17 adapter is essentially a standard 608 skate bearing pillow block with a NEMA17 motor mount pattern. This allows the other end of a long drive shaft to be supported using the same bracket work that is supporting the NEMA17 motor.http://blog.openbeamusa.com/2012/05/29/in-depth-608-bearing-adapter/Each of the mounting bolt holes contains a captive hex nut geometry. You can use this to capture either a DIN934 compliant nut, a nylock nut, or the head of a hex head cap screw.