NEMA 17 Sledge assembly
The Figure 11 shows the Mark 1 and 2 version with the cross member threaded for framing adjustment and bolted to the side members. For the Mark 3 the cross member is a flat plate fixed to the ends of the side members. A set screw is fixed through the centre of the plate to provide the threaded rod for framing adjustment by use of nuts, see Photograph 14.
NEMA 17 Chassis layout
The Figure 12 is suitable for making any Mark. For Mark 1 and 2 the NEMA 17 motor is at the top so the chassis is rotated clockwise about its right hand edge. For Mark 3 the NEMA 17 motor is at the bottom so the chassis is rotated anti clockwise about its left hand edge. The motor is always fitted to the rear of the chassis. See Photographs 1, 2, 25, and 26.