Increasing the screw size means the
hole in the brush housing that the
screws pass through also needs to
increase. Be careful drilling the hole
where the leads come through, as it is
easy to damage the wires.
assembly. One of the assets
of the T- 64 motor is that it
is already geared down to
the appropriate output speed
in a fairly compact form
factor.
However, to accomplish
this compactness, the motor is
designed with the output
shaft of the armature mating
directly to the first stage gear.
Any change to the orientation
of the armature in relation to
this first stage gear can
damage the armature and
gearset. So, in order to ensure
that this assembly stays intact and
tight, I machine the mounting plate
to accept a 1/4 20 thread, and use a
set of graded cap screws (McMaster
part number 91251A090) to
assemble the motor. The larger and
higher quality fasteners resist
stretching, and the durability has
been greatly improved. There is
virtually no weight change from
stage 2 to stage 3.
For combat use (with
whatever stage modification you
have on your motors), you should
frequently check the motor
assembly for tightness on all the
fasteners. I check mine after every
match. This may seem extreme, but
should be considered really for
every motor from any
manufacturer. Some of this is
due to vibration, and some
due to stretching, but it can
be astonishing how much
things can loosen in just one
match.
A final modification that
is cheap and easy is to wrap
electrical tape around the
outside of the brush housing
to confine the brushes. It is
extremely rare to actually see the
brushes pop out (I have only seen
this a few times, and never on an
NPC), but it is certainly possible and,
of course, the fix is really simple.
Here we see all the versions. Right
to left we have an unmodified new
motor, stage 1 with shortened brush
housing and coupling nuts;
stage 2 with machined 6061 mounting
plate; and stage 3 with larger cap
screw fasteners.
SERVO 08.2010 35
