Basing all m3 nut trap sizes off ISO 4032
For the captive nut traps used in the actuator, stage, and stand:
The calculations now use sizes specified for the M3 nut in ISO 4032.
There is no geometry changes except for rounding which results in a ~1um change which is 10x smaller than the smallest step size on the Prusa Mk3.
nut_from_bottom removed as it is unused.
It could more cleanly be recreated using m3_nut_hole (see below) and hole_from_bottom.
nut and nut_y become m3_nut_hole and m3_nut_hole_y
According too ISO 4032 maximum flat-to-flat distance of an m3 nut is 5.5mm (minimum is 5.32mm). As the corners are rounder the minimum width across corners is specified as 6.01mm.
As 3D printers slightly undersize small holes, 5.7mm is chosen as the standard nut trap width. giving 0.2mm clearance with the flats and still 0.31mm interference when trying to rotate the nut.
There is also a tight option for m3_nut_hole which sets the trap width to 5.6. This should be the same as the gears have been for years.
This is the size of the proposed slot overlayed on the maximal and minimal nut size:
Use new m3_nut_hole function for condenser nut trap
In the condenser the nut trap (see clamping_bolt_and_nut) was specified yet a different way. This time the circumscribed circle was radius 3.3mm. This gives a width across faces of 5.715mm. Baring the 15um tollerance, this is the same as the new m3_nut_hole, so this has been changed too.
Further discussion
These changes:
- Remove the last "fudge" terms from the code base.
- Replaces many of magic numbers with numbers pulled from ISO standards
- Only allows M3 traps. If we wish to use other nut types we can do similar calculations, rather than guessing the nut sizes off major diameter
Test prints still needed but this should close a number of issues