SAE Mendel
Release status: Experimental
| Description | Building a Mendel entirely from SAE hardware/fasteners.
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Summary
An attempt to build a Mendel from 100% SAE components. In Canada (and USA I hear) SAE parts are not only MUCH easier to find, but are much less expensive as well... This should help reduce the price, and make sourcing parts a lot less painful for those of us on this side of the pond.
I've begun my build, and I'll be making basic jot notes here as I go... Once done, I'll photograph, and update a BOM for the SAE build, so that others can recreate my results.
Notes
- Using 8-32 screws instead of M4 (diameter 4 mm --> 4.17 mm)
- Using 5/16 inch (7.938 mm) smooth rod instead of 8 mm smooth rod -- the difference is about half the thickness of a sheet of paper; you probably won't even notice the difference.
- Using 5/16" threaded rod instead of M8 threaded rod (diameter 8 mm --> 7.94 mm; pitch 1.25 mm --> 1.41 mm)
- need to calibrate the steps per MM number in the firmware during commissioning
- At least one functioning RepStrap used 1/4-20 threaded rod: diameter 1/4 inch (6.35 mm), pitch 1/20 inch (1.27 mm) -- Builders/Frank#Calibration and Testing
- Using 6-32 screws instead of M3 (diameter 3 mm --> 3.51 mm)
- Bearings from Ultimachine that I got are just a hair too small for the 8-32 screws (like .05mm) so I had to mount them in my drill press and file down the threads by a hair. nuts still work fine, and now bearings fit, but going forward might want to get different bearings.
- SAE nuts are a little bigger than metric. Trapped nut holes are a pain. I can make the 6-32 nuts fit, but not 8-32. So that means dropping the screw sizes for those spots as well... We will see if this causes problems. The fit is still tight but it works.
- SAE 8-32 washers are higher diameter than M4, so they are too big when put against a bearing (touches outside of bearing). So need to use 6-32 washers and they work perfectly. (note 6-32 washers will only fit on an 8-32 screw after the filing trick I mentioned above)
Imperial Reprap SAE
These pages should be merged such that both pages do not attempt to cover the duplicate topics.
Folk, I'd suggest just folding this in to SAE Mendel.
this page is the compiled location of all metric to imperial or SAE that I have found as well as a conversion of my own.
the full list of metric parts for a mendel is at this link Mendel-m4-assembly-data-sheet.ods
a list of conversions of proper sizes is found at SAE Mendel.
a full list of parts adapted from the Mendel build guide will be attached soon
a complete SAE prusa is attached here SAE Prusa Mendel.
See also
- SAE Prusa Mendel
- Mendel Drawings in Imperial units
- RepRap forum: About the Smooth Rods
- RepRap forum: "Questions about a Mendel build" has some comments about substituting Imperial sized parts for metric sized parts.
- The Tommelise project has a "Getting parts for Tommelise" page with tips for people in the US trying to buy parts for a RepStrap.
