Before we can build our wind turbine there are a few tools we
need to make. We'll need to make moulds for the magnet rotors and the
stator, and we need to make a coil winder. It's simply a spool made
from wood, with a crank that we can wind our coils on. The next couple
of pages will detail exactly how we made ours, but the idea here is
simple and there are surely many simpler ways to do this. Some of the
thoughts that went into this design included: having a fairly large
crank which makes handling thicker wire easier, and having the back
disk oversized, with steel pins so that we can change the form of the
coil and build different/larger sizes of coils if necessary. Ours is
also constructed like this because these were all materials we had on
hand. Your situation may be different. For a one off project, this
could all be simplified some. Before building this it might be helpful
to read the section on building the stator so you understand how we use
this tool - that will help you to understand why we make it this way,
and give you ideas about other possible ways to make a good coil
winder. Listed below are all the parts we'll require for this project.
- ¼" Plywood disk 6" diameter
-¼" Plywood disk 4" diameter
-3/8" plywood rectangle, ¾" x 1.5"
-5/8" plywood disk 6" diameter
-1" wooden dowel 2.5" long
-1.5" steel square tubing 7" long
-1" x ¼" steel barstock 5" long, qty 2
-5/16 - 18 bolt, 3.5" long
-5/16 - 18 bolt, 2.5" long
-¼" SAE washer, qty 2
-5/16 - 18 wing nut
-16 Penny nail, qty 5
First step is to cut out some metal parts. I find the portable
metal cutting band saw fast and easy, but a hack saw, sawzall or even a
torch would work fine. In building wind turbines we often have to adapt
a design to accommodate the tools are resources that are available to
us, sometimes this requires some imagination.
Whenever we cut metal there are sharp burrs at the cut. It's
nice to clean up all our cuts (and welds) with a grinder. Pictured
above George is grinding the cuts (he should be wearing a face mask).
Here is the square tubing we cut that supports the coil
winder. We need to cut it off square at 7" length, and drill a 5/16"
hole through it.
Cut two of these 5" long from 1" x ¼" tubing. One will be
welded to the bottom of the tubing. The other requires a hole to be
drilled and tapped 5/16" - 18. This one will serve as the crank, and
the handle will screw into the tapped hole.
Make this part from a 1" diameter wooden dowel. Overall it's
2.5" long, and we drill through 21/64" so that it turns freely on the
5/16" bolt. We also need to drill in 5/8" with a 5/8" drill bit to
accommodate the head of the bolt.
We cut the dowel off with any saw, and then drill it out on
the lathe. While it's on the lathe it's nice to round the edges and
sand it a bit. If you don't have a lathe, you could do this carefully
with a hand drill or drill press, or - if it's just for one machine the
wooden handle is not very important, it just makes for more comfortable
Drill a hole (9/64") through the 3.5" long bolt. The hole
should be drilled on center at 2 3/8" from the bottom of the bolts
head. The 9/64" hole is a good diameter to fit a 16D nail pretty
The nail serves as a pin to lock the spool to the shaft (the
bolt is the shaft)
Make 3 wooden disks. One is of 5/8" plywood (I prefer Baltic
birch for this) and is 6" diameter. Another is also 6" diameter, from
¼" plywood. We also need a smaller 4" diameter disk (in some of the
pictures we show a larger diameter disk on the front of this coil
winder that's been cut on two sides down to only 4" tall with two
slots. To avoid confusion just make that disk 4" in diameter and keep
the slot on one side as described later in the plans). All of these
need a 5/16" hole in the center. The 6" dia 5/8" thick disk needs a
slot cut to accommodate the nail we use for a pin. The slot should be
about 1.4" wide and deep, and 3.5" long so that a 16 penny nail with
its head cut off fits in there. Both the 6" dia 5/8" thick disk, and
the smaller 4" disk need 4 9/64" holes drilled as shown in the picture
above. These holes will accommodate pins around which we'll wind the
coils. Take the 6" diameter ¼" thick disk, and drill 4 holes, 3/32"
evenly spaced on a 5" diameter, and run a countersink in them. We'll be
using wood screws to attach this disk to the thicker one, and we want
the heads flush with the plywood.
It's important that holes line up nicely here. I would suggest screwing
the smaller disk, and the thicker 5/8" disk together and drilling all
the holes together.
Cut a piece of 3/8" plywood rectangular as shown above. It's
1.5" tall, and ¾" wide. Drill a 5/16" hole through the center. This
serves as a spacer between the disks.
Weld the 5" long bar stock that has no holes in it to the
bottom (the end furthest from the hole) of the square tubing. This
serves as a base so that we can clamp the coil winder to a workbench.
Put the shorter bolt (2.5" long) through the wooden handle and
thread it into the 5" long bar stock which has been drilled and tapped
to accept the bolt. Put a washer in between the handle and the bar
stock. Thread the bolt in so that the threads come flush with the back
of the bar stock, and the handle should turn freely.
Turn it over and spot weld where the bolt is through the bar
stock -this assures that the handle will never come loose.
Take the longer bolt (the one with the hole drilled in it) and
weld it to the other end of the handle as shown in the picture. It
needs to be square!
Put a washer over the bolt that's sticking out (we always want
a washer between any part that turns, and any part that doesn't) and
insert the bolt through the hole in the square tubing.
Put another washer on and then put the 6" diameter ¼" thick
disk on. The countersunk holes need to be pointing back, towards the
Insert the pin through the shaft and center it.
Put the 5/8" thick disk on the shaft so that it fits over the
pin that's through the shaft, and bring it tightly against the ¼" thick
Use 5/8" long wood screws to screw the two disks together
coming in through the back of the coil winder, through the 4 holes we
drilled and countersunk earlier. The screw heads need to be flush, they
must not stick out.
Put the small rectangular spacer on and align it so that its
in between all the 4 holes which will hold the pins around which the
coil is formed. Tack it there with a touch of glue so it doesn't
Cut a slot in the front 4" diameter disk as shown. It should
be about 1/8" wide and should come right to the center, and stop
between the two pins that are nearest each other. We'll start winding
the coils from this slot and it needs to be centered at the narrowest
part of the coil.
Cut 4 16 penny nails and cut them 1.125" long (including the
head). De-burr the ends you've cut (so they're not sharp). Once the
coil winder is finished, we'll insert these through the 4 holes in the
front (4" diameter) disk and they'll also go into the holes in the rear
disk, so that the disks are pinned together and the pins will be
supported both in the front and in the back. These 4 pins will form the
center of the coil.
Put the front on and use the wing nut to hold it on there.
(Ours which is featured in the pictures uses a normal nut - a wing nut
is easier though) The coil winder is finished, we'll discuss how to use
it when we start making the stator.
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