FIGURE 2. Cutting wall blanks.
The design used an off-the-shelf width of UHMW
(from www.mcmaster.com), so to cut the basic outline
of the side and end walls I simply marked everything out
using the templates, and then cut everything to size
using a miter saw with a fine tooth blade (Figure 2). I
ordered an equal amount of both black and white
UHMW, so the bots would be different colors for easier
This quickly resulted in a big pile of wall blanks
(Figure 3). The UHMW was slightly oversize, but not
enough to affect the parts. The templates (Figure 4)
were then used to add all the various mounting holes
required in the part.
I then simply clamped the blank and the template
together, and drilled through all the holes in the
template to produce a set of parts (Figure 5).
In order to make the motor mounting blocks, I used
a stop fitted to the vise on my mill to consistently
position the UHMW strip under a 1” forstner bit
(Figure 6). These bits are designed for cutting wood, but
they also work well on UHMW. I would position the
strip, bore the hole, and then use the template to mark
off the required length and cut off a mounting block
(Figure 7). This procedure was repeated until I had
produced all the required blocks.
Each block requires two holes in one side to mount
it to the chassis. To accurately position these holes, I
made a small jig out of a scrap block of aluminum
SERVO 03.2013 27