Prusa v2 x-end-idler z-axis captive nut holes too big

Im currently upgrading from the original Prusa Mendel (SAE) to the Prusa v2 LM8UU.....Im planning to use SAE hardware (which I thought I read was compatible with the v2 design).

I just printed out the LM8UU version of x-end-idler.stl but the hole for the z axis captive nuts seem to be way too big. A 5/16th nut just spins completely around in there, and an M8 nut can just about spin all the way around as well.

My printer is pretty dialed in and everything else i print comes out just about dead on.

I have a basic understanding of OpenSCAD, and im wondering if maybe i need to edit the configuration.scad file and change the M8 Nut diameter to something smaller (currently it's set at 0), then recompile the x-end-idler and other relevant files?

It seems wierd though that it wouldn't be correct to begin with... Or am i missing something...

Thanks!

Edit: I just added a few pics.

Edit #2: I just realized that the M8 Nut diameter is actually set to 14.1mm in the metric.scad file, and that's exactly how large my captive nut slots printed. It's wierd though cause all my M8 nuts are only 12.9mm, do i just have weird M8 nuts or something?

Edited 2 time(s). Last edit at 02/14/2012 01:01AM by daufhammer.

daufhammer Wrote:
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It's wierd though cause all my M8 nuts
> are only 12.9mm, do i just have weird M8 nuts or
> something?

Just measured my nuts . They are 12.8mm - so your nuts are about the right size.
Not sure about the metric.scad file though.

Ok, well at least im not crazy, or don't have abnormally sized M8 nuts....

Well, I just decided to edit the configuration.scad file and uncomment the m8_nut_diameter line and changed it from 0 to 12.7 which is the size of my 5/16 SAE nuts. I recompiled and exported the file as .stl and everything looks great. I even pulled up at the same time both the old .stl and the new one i created and could see that this did indeed reduce the size of the captive nut slot, so i think I am good to go.... just need to re-print it now!

Edited 1 time(s). Last edit at 03/18/2012 04:06PM by daufhammer.

You still should leave some clearance, otherwise it might be very hard to fit the nut in the hole. Something between 0.5 and 1 mm should do ?

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Most of my technical comments should be correct, but is THIS one ?
Anyway, as a rule of thumb, always double check what people write.

Metric fastener sizes

M8 with across flats is 13mm (according to specs)