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RE: [TCML] Need coil winding advice
Jim (& other coil winders),
Here is what I do (sorry - no pictures):
1) Get a threaded rod that is about 4 inches longer than your coil form.
1/4 inch diameter works fine.
2) From 3/4 or 1 inch scrap wood cut two round inserts with slanted edges to
fit about half way into each end of your coil form. Drill a hole in the
center of each for the rod to go through.
3) Make a wood pulley out of 1 inch scrap wood. Cut out a round piece about
6 inches in diameter, drill a 1/4 inch hole in the center, put a 1/4 inch
bolt in it & tighten with washer and nut, chuck this in an electric drill
clamped in a vice (or use a drill press), spin it up and use a round file to
file a round groove in the center of the edge, thus making it a pulley.
4) Put the round inserts in your coil form, put the rod through them, slide
on the wood pulley on one end, and secure the rod with washers and nuts so
there is an inch or so sticking out past the nuts at each end. It is a good
idea to tighten a second nut on each end to make sure nothing comes loose in
the middle of your winding process.
5) Make wood supports that the rod can pass through to support the coil
assembly horizontally about a foot off of a support base. The supports need
to have some sort of bearings through which the rod ends pass. Real
bearings are best. Otherwise, some quarter inch thick pieces of metal will
do. (If you don't have metal bearings, the spinning threaded rod will "eat"
into your wood supports).
6) Make a small wood grooved pulley about 1 inch in diameter, drill a hole
in the center, and put a quarter inch two inch long bolt through it, tighten
on a nut, and chuck it into an electric drill. Mount the drill horizontally
on your support base so that the two pulleys align. The electric drill is
your drive motor. With its built in gear reduction plus the reduction with
your pulleys, you end up with a good coil form RPM with plenty of torque.
7) Make a belt using some about 1/4 inch diameter rubber (surgical) tubing
which you can buy at a hardware store. This material has good gripping
qualities, making it a good belt. Use just enough tension to give the
needed torque, but which also allows you to manually turn the form backwards
if you need to undo an overlapped turn, etc. Use your imagination to invent
a way to join the ends together. I ended up "sewing" mine together with
8) If your drill is variable speed, then you can set the speed so the coil
form rotates 1 to 3 times a second. Otherwise, a lamp dimmer or small
variac can control speed. Be sure it turns so the top of the form rotates
away from you - the belt can be a figure-eight if needed.
9) Others mount their reel of wire so it can turn freely and spool off the
wire. But you then have to cope with the inertia of the turning reel of
wire, which can lead to wire breaks or a mess when it coasts to a stop. I
prefer to put the wire reel with one spool end flat on the floor, so the
wire easily pulls off past the other spool end. The twisting of the wire as
it comes off the reel poses no problem.
10) On your coil form, put 4 to 6 lengths of double sided tape down the
length of your winding area. This secures the winding during the process so
you can stop winding as needed.
11) I let the wire pass through a rag or some thin foam rubber held in my
hand to control the tension (and prevent wearing a groove in my skin!)
12) A foot switch is a necessity. You can make one out of a door bell
button or other momentary push switch mounted on a piece of wood.
13) You really don't need a turns counter. Just take some of wire you will
use for your secondary, wind exactly an inch long coil of it on a nail or a
pencil, then count the turns per inch. Then figure out how long your coil
needs to be for the desired number of turns.
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Jim Harvey (UDN)
Sent: Friday, February 27, 2009 8:57 AM
To: 'Tesla Coil Mailing List'
Subject: [TCML] Need coil winding advice
Greetings... (sorry if duplicate)
I am designing my first TC and need to build a coil winder. My first
secondary coil will be:
Length: 18 inches
Wire: 26 AWG
Since the coil is not too long, I am thinking about a plywood frame
supporting a motor, turns counter, and arbor. A foot switch would be used as
well as some type of speed control.
Can anyone point me to some links that show working units?
73 & Stay Vertical,
Jim Harvey (W7YV) - The Great Curmudgeon
P.O. Box 18009
Salt Lake City, UT 84118
FIST # 13337
SKCC # 3194
"Calling CQ was like a box of chocolates. You never know what you're gonna
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