SAE Printed Parts prusa

A general question about what SAE printed parts actually means.

I know that as far as holes go (rods) it means 5/16". What about the nut traps? 6-32 sizing comes with the SAE vitamins kit, but he nut size is substantially bigger than an M3 nut. The printed parts I have seem to have M3 sized nut traps, but my SAE vitamins kit has no M3 bolts long enough for the Z-axis top clamps (4 bolts).

Is this a "mis-print" of parts and those M3 nut traps should be for 6-32? Or should M3X25 bolts and extra nuts have been included in my vitamins kit?

Thanks in advace!

The traps on the SAE chassis are 6-32. The extruder is still metric.

6/32 SAE nuts apparently don't have a standard size. I've got 2 of them here with different outer diameters. A small one that measures 5.4mm across the flats, and a larger one that measures 7.88mm. Go figure.

You can find metric hardware with varying sizes too. It depends on which standards the components were manufactured to. ANSI/ASME metric, DIN, JIS, ISO, etc. That, and there are difference types of nuts and different grades within each standard which may have different dimensions and tolerances. The thread forms themselves are usually consistent (except tolerance classes), and will interchange in almost all cases.

I suspect that most people designing printed parts measure whatever they have with calipers, and aren't aware of what they actually have. If they buy their next batch of parts from a different supplier, they might end up with something that doesn't fit the parts they just designed.

And then there is printer calibration.

I think all the metric nut diameters are standard. There are different thickness's, etc, but I have never known the nut, or hex head diameter to vary.

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I haven't worked with enough nuts to say otherwise. I have worked with enough hex head screws to know that JIS head sizes are different from the metric fasteners you get here in the US. I had assumed the same would be true for nuts and other fasteners. I should probably look into this, but I won't have time until after the holidays. After which I will probably have forgotten.