[Kevan]

Kev (OXO) & Greg (MrF) have both made versions for their tyre truers...I have a RSM3 truer which is different again so used the files Greg kindly provided and modified it.

This remix uses Slot car round magnets we normally stick together and never use, the 8mm diameter ones push into the 'magnet joint' and 'magnet short arm'.  I made the 'magnet joint' 6mm thicker to centralise the sliding plate, in the video you can see the temporary mod I made with two pieces of 3mm thick expanded foam.
If you print two 'magnet joints' you can spin the slider round and use fresh sandpaper.

The RSM 3 truer should be a snug fir into the 'RSM base unit' and can be secure in place with two 'roller' discs but may not be necessary if the truer is snug enough.

The 'gantry' is a snug fit over the 'RSM base unit', again two 'roller' discs can be held down with screws but again may not be necessary if the fit is snug enough.

The 'motor arm' slides onto the shaft of the reciprocator motor. The motor I used is a
'Geared Micro Motor Speed Reduction Gearbox - 12V ⋅ 30 RPM'

I soldered wires from the reciprocator motor to the truer motor and run it at 4v.  (5v seems to work better for super soft tyres like Scaleauto A-S25's and SlotIt G25's)

HERE on thingiverse