groove accurately at both speeds. Any drift due to
belt slippage or other machining factors is compensated for by the tone arm’s ability to pivot laterally.
Metal Parts
I made most of the parts out of aluminum, steel rod,
or nylon, using a small lathe and milling machine.
Complete plans are at makezine.com/14/diymusic_
phonograph. First, I made the base plate out of
2"-thick aluminum. I indexed the mounting holes
using the digital readout of my milling machine
because it was available, but that was probably
overkill; a skilled operator could do it manually
with a ruler, scriber, punch, and drill press.
Then I made the 6 uprights to hold the drive shaft,
lead screw, and carriage rail. These are identical
pairs of aluminum blocks or rods machined and
tapped in various ways (see the plans) and mounted
to the base plate with ¼"× 20 cap screws. I also
turned two 1" pieces of ¼" steel dowel in a lathe to
sharpen them to 60° points, which fit into the lead
screw uprights. The points hold the screw horizontally so that it can rotate.
The drive shaft, lead screw, and carriage rail
themselves are made from standard steel rods. The
carriage rail is simply a 7" steel rod cut to length.
The lead screw is ½"× 20 threaded rod, faced and
center-drilled at both ends with a dab of grease
for the points. The drive shaft is 2" steel rod, held
in its uprights by a pair of Oilite bushings. I used a
lathe to turn a ¾" section of the rod near 1 end into
a crowned (rounded) drive pulley, for the 1: 10 drive
configuration. Flat belts stay on crowned pulleys
because they gravitate to the highest point.
The phonograph also has 2 crowned drive pulley
pieces made of aluminum, one for the motor
underneath to power the drive shaft, and the other
for the drive shaft to power the lead screw in the 1: 5
configuration. Both are held in place by grub screws
through their flanges.
Nylon Parts
I used nylon to make other components. I turned
the phonograph’s 3 driven pulleys on the lathe. The
motor-driven pulley has a flange for a grub screw to
secure it to the drive shaft. The 2 driven pulleys on
the lead screw are simple disks, secured on either
side by ½"× 20 nuts, thinned down on the lathe, and
washers; 2 more washers in between the pulleys act
as spacers.
Opposite the pulleys on the drive shaft is the
tapered nylon mandrel that holds the cylinders,
along with a sliding, tapered sleeve that helps keep
them snug. I also made both of these on the lathe,
using the compound slide to attain the angle on the
sleeve and offsetting the tail stock to achieve the
angle on the mandrel.
For the tone arm carriage, I cut a block of nylon
and drilled 2 parallel holes along its length 1" apart:
a smooth 8mm hole that slides over the rail, and a
½"× 20 threaded hole that engages with the lead
screw, which drives it. Then I cut away the top half
of the threaded hole to create a half-nut, so you can
disengage the carriage from the screw and slide it
back to the beginning of the cylinder. A metal weight
on the cylinder side of the carriage acts as a counterweight to push the half-nut up against the lead
screw, with the rail in between acting as the fulcrum
(Figure A, following page).
Box, Motor, and Speed Control
The box for the phonograph I made out of pine,
cutting the pieces on a table saw, joining them with
screws and glue, and finishing with some wood filler
followed by a sanding and a lick of stain and varnish.
I screwed the fan motor to the underside of the
base plate, which simply rests on the inside lip of
the box. I made the lip with a couple of passes on
the table saw (Figures B and C, following page).
A long strip of nylon screwed to the box runs flat
alongside the base plate. This carries the phonograph’s speed control, which is an off-the-shelf wall
control for a ceiling fan. On the back side of the box,
2 nylon donuts reinforce the holes for the power
and (mono) audio cords.
Tone Arm, Cartridge, and Needles
My tone arm came from an old BSR stereo turntable, and I rewired the cartridge to read cylinder
recordings. The challenge is that cylinder recordings
are vertical, where the groove varies in depth. In
contrast, mono 78rpm and 45rpm discs are lateral,
with a zigzagging groove, and 33rpm stereo LPs
combine both approaches. To convert a stereo
cartridge to read vertical tracking as its main signal,
reverse the wires on either the right or the left channel.
If that doesn’t work, reverse them on the other side.
The result should be clear sound from both speakers.
To play 4-minute cylinders, the cartridge holds a
sapphire stylus for 78rpm records.
Make: 143
