AMATEUR RADIO

John J. Marlatt K7AGI
N. 6707 Standard #3
Spoka.ne WA 99208
Build
a
$2 Drill
- - and put your razor to work
I
f you need to drill small
holes, th is little motor is
handy and inex pensive. It
easily drills thr ough 1{8" of
bakelite, fiberglass or aluminum.
It beats putting a #60
(.040") drill in a motor and
immediately breaki ng the bit.
Small sizes need speeds up to
7000 rpm or more.
The following describes
conve rsion of Sunbeam
"Shavemaster" razor motors
into usefu l hand-held drills.
Model "W" seems to be plentiful
at local salvage sto res of
Goodwill Industries, St.
Vincent dePaul and Volunteers
of America, at prices
from 15¢ to 504.
The procedure is as fo l­
lows: Remove two screws
from the bottom of the
plastic case and lift out the
works. Brush off any dust
and cli ppings. Remove the
retaining washer from connect
ing rod and take off the
nyl on rod. Remove 4 screws
and discard all oscillating
shaver parts, but retain the
large diecast plate.
Unsolder two wires from
ac power input post.
Remove two brush holder
clips, keeping your fi ngers
over the holes to prevent the
brush springs fro m flying
away. Remove the 4 hex nuts
holding the end bell to the
motor frame. Sli de out the
armature.
Carefull y remove the two
motor brushes. If they are
less than W' in length they
shou ld be replaced (shaver
repair stores have them).
Brush out carbon dust, etc.
Place the armature in a
vise and unscrew the crank
(counterclockwise). Discard
the crank. Run a 4-40 tap
into t he hole in the shaft.
This is preferably done in a
metal lathe but can be
successful ly performed by
hand . On the reverse end of
shaft, saw a screwdriver slot
with a miniatu re hacksaw
blade. Fi le off any burrs left
by the saw.
Place a drop of oil on each
bearing and, if there are
spacer washers o n the shaft,
put at least one o n the commutator
end for a th rust
bear ing. Re assem ble the
motor and solder the wires
back on power input post.
Now, test the motor.
Take the plate saved from
shaving mechanism and saw
off the bosses or projections
that held the shaft. File it
smooth, and round off all
corners and edges as you hold
this in your hand after
assembly. Replace on the
motor frame .
Drop the motor back in
the plastic case and measure
points o n the ho using even
with ends of the armature
shaft . Dri ll W' holes in each
end . Enl arge the crank
opening to W', preferably
with a tapered reamer, as it is
very easy to split plastic with
a large drill.
O b ta in a steel 4-40
machi ne screw about one
inch long, and cut off the
head , leaving it about W' in
length. Smooth the threads in
a 4-40 die if possible. Screw
this into armature shaft.
If you have the original
power cord with the spec ial
120