Trapezoidal screw rail and jaws for rotating vise

Things needed:
8mm x 200mm trapezoidal screw and nut
2x m3x8 screw (for rail alloy)
4x m3x8-16 screw or 3.0x8-16 screw (2 will suffice) for the trapezoidal nut
2x bearings 688 (8x16x5)

The knobs go in very tightly, so you should be ok without screws. I tried drilling the trapezoidal screw. On one side it worked, on the other side the hole came off so I pasted the other knob.

Wider jaws, longer rail and trapezoidal screw on bearings instead of metric.