Simple i3 x-axis strain relief bracket

(for x-axis idlers with offset leadscrews)

(v1.1 update, added ability to adjust arm lengths in the scad file)
(v1.2 update improved customizer support)

A design flaw in many Prusa i3 X-axis setups is when tightening the x-axis timing belt, the tension pulls on the z-axis straight rods and leadscrews, pulling the leadscrews off vertical and possibly bending the z-rods.

One solution is to print a complete new x-axis setup with tensioners that load the x-axis rods instead of the z-rods, like:

Smooth X-axis for Prusa i3 with Leadscrews
by MazaaFIN:
http://www.thingiverse.com/thing:1103976

or

Prusa i3 improved XZ axis
by jkoljo:
http://www.thingiverse.com/thing:372056

But for a beginner like me they seem like quite challenging print projects to work up to. One day though!

I have a MaxMicron Prusa i3 clone with an x-axis setup where the leadscrews are offset from the straight z-rods, like the HIC design by Zeigbo:

HIC Prusa I3 X-axis Motor Carriage OFFSET Z-AXIS RODS
by Zeigbo:
http://www.thingiverse.com/thing:712896

(This offset lets all four of the leadscrew mounting screws be used, unlike many inline versions where only 3 of the four are used, which is nice.)

The offset means the top and bottom of the right end idler is clear, and gives room for a very simple bracket that can solve the strain problem well enough to keep going and work up to a really big print!

So, I have designed a simple clip-over bracket to put the x-idler stress back onto the x-rods. Not as fancy as an actual tensioner, but a lot simpler.

Here is a parametric scad file that fits my MaxMicron, and probably any printer with an idler like the "HIC Prusa I3 X-axis Motor Carriage OFFSET Z-AXIS RODS"
but it can be adjusted for other dimensions if needed. I used 5mm thickness, but it might be worth trying different if you like.

The STL is the most likely fit, saved from the scad file, set to use M3 captive nuts and 20mm M3 screws. The scad has option for M4 screws, and M5, but the M5 option may need some work to get the larger nuts to fit outside the x-axis rod holes without weakening the bracket too much. I use M3 just fine.