Primary Coil Construction

My primary is made of 1/4" refrigerator tubing obtained from a home center.

Here is my primary coil assembly:

:

The base of the primary is cut from a sheet of 1/4" Lexan (Polycarbonate). I used a router with a compass attachement to cut the circles. The coil is held in comb like strips of polyethelene cutting board. (We have a very nice small cutting board now which works very nice for cheese.)

I cut the slots on a table saw and shifted the pattern of slots for each comb so that I would have a nice evenly spaced spiral.

The keepers were cut from scraps of 1/4" acrylic sheet. The same is true for the supports for the strike rail. Note that the strike rail is not a complete circle. The white tube near the top of the picture holds the ends of the strike rail in line. Connecting the ends of the strike rail into a circle would create a shorted turn in the transformer and greatly reduce performance.

Here is a close-up of the coil:

You can see the number 6 self tapping screws I used to hold things together. The strike rail is held using P-clips.

Heres the connection to the strike rail. I made a copper clip and soldered it to the strike rail.

This next photo shows the inside connection of the primary:

I flattend the end of the tubing and drilled it for the screw lug.

I needed more than the 50 feet of tubing contained in one package. I spliced the needed length with a small piece of brass tube. I sweated the splice carefully and ended up with a clean splice.

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