(Figure 1) to do this.
I was careful to leave a small gap
between the motor body and the
gear to ensure they would not bind
up when running. A few minutes of
work, and all three were complete
I had intended to completely
machine the two thick UHMW walls
but decided to save time by having
them watercut along with the
Watercutting can only produce
2D shapes, so first I modified the
parts to remove any of the pockets
and recesses, then generated a DXF
file of the outline and through
openings (Figure 3).
You can see a 1" square added
to the DXF; this is used to check that
the scale of the part is correct and
you don't get a part that is much
bigger or smaller than expected!
(Yes, it has happened to me). I
ordered the watercut parts from
Team Whyachi, remembering to
specify "zero draft" on the sides.
A conventional watercut part has
an angled slope on the sides cut by
the jet. This doesn't matter too much
SERVO 03.2014 29
FIGURE 2. Motors with gears.
FIGURE 3. DXF for watercutting.
FIGURE 4. Adding chamfers to rear.
FIGURE 5. Watercut parts.