[TowerTalk] Another DIY Air Wound Coil Form

[David Gilbert]

I recently posted a link to a method of using a 3D printed form to make 
an air wound coil like the old Air-Dux coils and I still think that's 
the most efficient way to do it, but that version results in a slightly 
tapered form.  Other variables are likely to have at least as 
significant impact on the final inductance as the taper, but mostly for 
aesthetic reasons (as well as just the challenge of it) I tried to come 
up with a design that gave a coil with a uniform diameter.  You can 
check out the result at:

https://www.youtube.com/watch?v=S6spyk1GRoo&ab_channel=DavidGilbert

Once again, I speak pretty slowly so clicking on the "Settings" gear 
icon at the lower right of the video to bump the playback to 2x speed 
might be in order.  A link to the OpenSCAD 3D files are in the 
description below the YouTube video.  Again, the files are parametric, 
meaning that you can define pretty much any combination of number of 
turns, turns-per-inch, and wire size that you may want.  Per a 
suggestion from W7TMT, I provided a hole down the center of the coil 
form (the diameter of which can be defined) so that larger coils could 
be turned on an axle.

For the same coil diameter, it is only necessary to 3D print one copy of 
the coil form pieces as long as the length is at least as long as any 
other coils you might want to make.  Multiple copies of the same coil 
require only multiple copies of the strips, and changes to the number of 
turns, turn-per-inch, or wire size also only require additional strips 
as long as the coil diameter stays the same.

For what it may be worth ....

73,
Dave   AB7E