Saturday, June 18, 2011

RepRap Step 1: Cutting

The first step of actual construction of the Prusa RepRap is to cut rod stock to length. The instructions on the RepRap wiki are for 1 meter lengths, and so, not much use to us here in the U.S. with stock that is a  yard long. For this step you'll need seven pieces of three foot long, 5/16" threaded rod.

We need to wind up with six pieces that are 370 mm long, two that are 210 mm long, four that are 294 mm long, and three pieces that are 440 mm long. In SAE measurements, that winds up in the neighborhood of 6 x 14 5/8", 4 x 11 5/8", 3 x 1/3", and 2 x 8 1/4". If you can use a ruler with a metric scale you'll find it much more convenient than going by the SAE scale.

I have developed a cut plan that makes the most of the stuff we have, and leaves pieces left over that you can use for building a second printer. But honestly, there is no great way of doing it.

Cut Plan; 36" threaded stock, in mm


This leaves enough for 1x370 and 1x210 pieces for your next printer.

Cut Plan; 36" smooth rod, in inches
13" x2 ~10"
16" x2 ~4"
16 1/2" x2 ~3"


A hack saw, a bench vise or a clamp, and a ruler will get you through the cuts. A file is nearly necessary, and using some of your 5/16" nuts will help a great deal. Optional, but recommended is a cordless drill to make threading the nuts a lot quicker.


7 x 36" long 5/16" dia. threaded rod
3 x 36" long 5/16" dia. smooth rod

How To

The general process is: first, thread on three bolts to the approximate length of the section to be cut. Refine the measurement by turning the center nut to line up one side with the precise spot where the cut should be made, and to lock the neighboring nut (on the outside of the guide nut) against it. The opposite nut is to smooth out the threads after cutting with the hack saw. Cut the rod, then file the ends flat.

RepRap Rod Cut Closeups from Kevin Wixson on Vimeo.

Cut the smooth rod to length. Obviously you'll just measure, mark and cut them because you can't use anything like the nuts as a guide.

Next up: build the frame!

I'm building a Prusa RepRap 3D printer and documenting the process in exhaustive detail. My intent is for others to be able to follow along as they build their own printer. As entertainment, the way a cooking program on TV is mostly for show, my own effort will fail. This is by design. If, however, you are sitting down with your parts splayed out in front of you and eager to get to work, we're on target! Dig right in.

- Posted using BlogPress from my iPad

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