Re: shaft fasteners for RSG?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Arpit Thomas" <arpit-at-inzo-dot-org> 

g'day; would it be worth persuing a solution like a properly machined disk 
for a coil based around 4 microwave oven transformers? Im kindov on a 
budget here you see.... maybe something like a static gapconnected to a 
compressor or a leafblower would be good enough?

*********** REPLY SEPARATOR  ***********

On 22/10/2004 at 9:16 PM Tesla list wrote:

 >Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
 >
 >
 >Don't consider Lexan for a large high power coil.  The heat will start to
 >melt the Lexan and send sparkgap shrapnel flying around.
 >
 >Use 1/2 inch dia. G-10 phenolic.
 >
 >A good design would be a 14 inch dia. G-10 rotor with 12 electrodes on a
 >12.5 inch dia. circle.  Use a cheap surplus DC treadmill motor (usually 2-3
 >hp) with a pulley and belt for reduction in speed.  Most of these motors
 >top
 >out around 3,000 RPM with a light load.
 >
 >Set the pulley reduction ratio to give you approx 600 pps (maximum) from
 >your rotor.  Power the DC motor with a standard 120 V 25 Amp rectifier
 >block
 >and use a healthy filter cap on the output for smooth DC power.  Use an RF
 >"hash" choke between the DC output and your motor to choke off any RF that
 >might feed back due to any spikes or induced currents in the sparkgap --
 >motor case.  Use one on both pos and neg legs.
 >
 >The treadmill motors are $30-$75 range or less thru surplus houses.
 >
 >This allows you to adj speed and pps for best results with your coil.
 >
 >Have a machinst to the layout and setup on the rotor (.0005" tolerance) and
 >then static balance it.  Don't do this at home as a do-it-yourself thing.
 >The rotors are a dangerous part of a coil setup and a quality machine shop
 >will do an excellent job.  Safety first --- it's a bit expensive but a lot
 >cheaper than buying one of your neighbors a new eye.
 >
 >We can machine you a rotor hub if you need one.  I would need to know the
 >shaft size on your motor.  Then take this and your G-10 to a local shop and
 >have them do the rest.
 >
 >Dr. Resonance
 > >
 > > I have started getting the urge to build a big coil again and
 > > I was wanting to do everything right this time. In the past,
 > > I simply used a bench grinder motor with the emory wheels
 > > removed and replaced with a lexan disc(s). I used the ex-
 > > isting emory wheel arbor to secure the lexan disc but I
 > > want to use better hardware this time around. I've noticed
 > > that most of the professional built RSGs have a sleeve or
 > > bushing cylinder that appears to go over the shaft with
 > > set screws to secure it to the shaft and about 4 set screws
 > > that secure the disc to the sleeve bushing. Home Depot
 > > and Lowes don't carry anything like this and I was won-
 > > dering where to get this type of shaft hardware (McMaster-
 > > Carr, I assume) and what name would it be listed under?
 > > I know that you can get G-10 sheets at McMaster-Carr
 > > also, but I found that I could also get G-10 at one of my
 > > local plastic suppliers for about 60% of McMaster-Carr's
 > > price.
 > >
 > > Thanks,
 > > David
 > >
 > >
 > >