The AM Forum

What would be a good, durable material to use as a non-conducting 1/4" shaft extension?  I'm thinking about using plexiglass rod, but is there something more durable?

My single FET class E rig uses a large bakelite knob on the tuning capacitor.  It's insulated, but my hand influences the capacitance a little bit while I'm tuning.  I want more isolation on my larger class E rig.

Jon

Fiberglass rod is what is usually used.

73DG

Go to  Mcmaster.com  .  On the left side, click on 'raw materials', and from there you can choose 'plastics' and from there 'rods' and even choose only 1/4" diameter.  Their basic product descriptions give a pretty good rundown on the properties of each type of material.  Take your pick.
Prices are pretty good, service is quick, and they are friendly to small orders as well as big company stuff.  They are my go-to shop for materials when I can't find something suitable in the junk box.

Home Depot 1/4 in. x 36 in. Oak Round Dowel $1.10

Sporting Goods Store

Arrow shaft.

Don W4DNR

Isolated shaft coupler.

https://www.amazon.com/Ceramic-Insulated-Shaft-Coupling/dp/B00LR0UDCW

I'm sure you can find cheaper.

Or,  piece of cutting board.   Cut a cube out of it,  drill and tap.   Insert 2 set screws,  tapped.


Problem solved.

--Shane
KD6VXI

Since there are no particularly high voltages involved, I like Pete's suggestion being a fellow Yankee thrifty type

Al

I used acrylic rod on my homebrew rig, the trick I found with it is to keep the length of the rod as short as possible, too long and it will start to feel like the shaft is twisting as you turn it. Just figure out how long of a section you need, score it, and snap it. It makes a nice clean break. http://www.ebay.com/itm/6-PIECES-1-4-DIAMETER-12-LONG-CLEAR-ACRYLIC-PLEXIGLASS-LUCITE-PLASTIC-ROD-/301485648733?hash=item4631f1eb5d

Thanks for all the responses.  I decided to go with Amazon for a fiberglass rod.  It's not as cheap as Home Depot, but they deliver. 

On another note, I've bolted both heat sinks on my new class E rig to an aluminum plate, making an assembly that can be added/removed from the transmitter.  It'll make assembly much easier since I'll be able to do it on the desk, and then transfer it to the RF deck. 

I'm also rearranging my shack to be an ultra-purist.  Now I'll just have two class E transmitters, my QRP 20 meter CW transmitter and an SDR receiver.  I'm probably going to disassemble my three 3-500 linear at some point.  Once I get this new transmitter going, I won't need it.  Plus, I'm still leery of having it around with kids.

Jon

Rubber hose of the type that does high pressure (but without metal weave in the rubber) makes
a very durable and stiff enough shaft coupler - get the 1/4" ID type. Two hose clamps, done...

driveway reflector on a 48" fiberglass rod. They were 1/4" diameter last time I used one. $2.18 each home despot
http://www.homedepot.com/b/Tools-Hardware-Hardware-Signs-Letters-Numbers-Driveway-Reflectors/N-5yc1vZc8fv

This was suggested to me here on this board long ago. credit where due.