Prusa Mk3 R2B x-axis modifications

I made some modifications to the X-axis motor and idler ends (denoted R2b). These are based on the original Prusa files, with the following modifications.

The idler pulley bolt has been reversed. This gives enough space for the walls surrounding the nut and bolt to be significantly thickened. In addition, the bolt socket and nut trap have been adjusted in size to remove slop around the bolt head and to make the nut socket a better fit, as per Geoff Gregors work (see bottom of notes).

These modifications mean that the wall thickness and nut trap dimensions for the nut side changes from 2.5mm (wall) and 2mm (nut) to 2mm wall and 2mm trap. The bolt side however, changes from 1mm (wall) and 2mm (bolt head socket), to 3mm for both. This side was the weak point and is now significantly strengthened.

You will need to switch out the nylock nut (3.5mm thick) with a standard nut (2mm thing). It's too tight with the M8 leadscrew otherwise. Use a bit of loctite to make sure it all stays solid.
Make sure when you screw the bolt through, that you don't go too far and scrape on the lead-screw.

The modifications to the motor end are much simpler. All that has changed there is that the elongated bolt holes that allow the rotation of the motor (for belt tensioning) have been extended, giving an addition 1 mm or so for belt tensioning.

Geoff Gregor's notes for his R2a modification:
"Summary: Nut pocket slightly bigger, screw head pocket much smaller, less damage, no more slop, screw stays aligned for happy printing (hopefully).

Ok, so after wrestling with my squeaking belt on x-axis stage I've come to the following conclusions. I Will list everything I can in point form. As with all this stuff its a whole bunch of little things that add together to make a problem:
* All of this relates to MK3 Prusa Rev R2 X-Idler Part
* The nyloc nut trap was under size at 5.37mm instead of at least 5.42mm
* this caused a lot of stress on the thin 1mm wall directly beneath the screw head at the front of the part and most of the time damaged it simply by seating the nut
* This meant that the 3.1mm diamter holes whilst aligned originally were not doing their jobs of holding the screw straight and which was then being done by the counterbore pockets for nut and screw head
* The nut was being held in the centre as it could not move
* The screw head however had a 6.0mm pocket and the screw head is 5.42mm which lets it move in approx 0.5mm and come out of alignment
* The screw head pocket is now 5.5mm and now has no slop
* I have printed and fitted this part and it seems good. however, I haven't done a whole bunch of printing yet.

NB. screw holes were never 'mis-aligned' on the R2 model they were just ridiculously easy to damage so that misalignment would occur. (and the instructions are basically promoting this to occur)"