Tesla Coil Winder

Once you start down the slippery-slope of Tesla Coil building, in addition to the “original” spark-gap TC’s, there’s SSTC’s (Solid State Tesla Coils), DRSSTC’s (Dual-Resonance Solid State TC’s), VTTC’s (Vacuum Tube TC’s), and more.   However, they all need resonators (coils).   After hunting around the ‘net for a while, I settled out on a nice design by Terry Fritz.   You might recognize his name from the famous “Terry Filter” commonly used to protect neon sign transformers (NST’s) from damaging RF & back-EMF energy in spark-gap TC’s.  His winder design can be found at:   http://drsstc.com/~sisg/files/SISG-coil/LittleWinder.pdf

I started with some nice, heavy Red Oak and a couple of kits from electronickits.com.   When winding your coils, you will be providing significant tension on the wire (at times), and the torque of the winding motor can flip light-weight winders right over.   This also uses a 36″ steel rod so longer coils can be wound:

The kits are the Bi-Directional DC Motor controller, and the 4-Digit Up/Down Counter kit.   I thought I’d try a Pulse-Width Modulation (PWM) controller instead of Terry’s linear voltage/current controller based on LM-350T’s.   As it turned out, neither gave me good control over the motor/gearbox I bought from Pololu.com.   Using the PWM controller, the motor wouldn’t start until the pulse-width was fairly large, then it would just “take off” (yow).  Needless to say, I was looking for a smooth-starting winder.   I ended up using a bench supply that has good current & voltage control.  This could be because the motor is fairly low-voltage (6 volts). Here’s the assembled kits:

The motor has a 4mm output shaft, while the winder rod & coupler are 1/4″.   A short piece of 1/4″ OD aluminium tubing with a small center hole was drilled out to 4mm to slip over the motor shaft.  A 6-32 sized hole was drilled into the side of the aluminium tube so the set-screw from the flexible collar could pass through it, and fasten nicely to the flat on the motor shaft.   A friend of mine, Jeff, thought that one up.   The micro-switch is going to be used to trigger the counter.  The base came out pretty well (if I do say-so myself); I used a couple of coats of MinWax PolyShades stain & polyurethane in-one (Pecan Satin):

I added a foot-switch to Terry’s design so both my hands could be free while winding.   It’s put it in series with the power; the 1/4″ plug has a bypass switch, so when the foot-switch is unplugged, the plug passes power (good for continuous slow turning while the HV finish dries).

So, here’s how it costed out (about $225 total):

4 digit up/down counter kit: $25.00
PWM bi-directional motor controller kit: $25.00
Gear Reduction motor & mounts (pololu.com): $22.00
Rod & bearings for winding support; connects to motor: $30.00
2 nylon pulleys from McMaster Carr, item 3060K21: $40.00 + shipping
Wood, screws & fasteners for base: $25
Electronics enclosure: $7
Fwd/Rev, power & micro-switches: $12
Foot switch: $20
Stain/polyurethane, brush, paint thinner: $15