I have spent the past two days, since my large spool of magnet wire got here, making a 120 turn really nice coil.It is the nicest coil I’ve ever constructed. Unfortunately that isn’t saying tooo much… I took pictures of it, but the jig I used was destroyed in removing the coil–and I forgot to take a picture. Anyway, it was difficult to make, and I used a lot of superglue. This was bad for a couple of reasons; 1.) Superglue fumes are bad. 2.) it enlarged the dimensions of the coil beyond a reasonable margin of error, causing it to hit the axel on the prototype galvo frame. Fortunately this was just a prototype, so I had the opportunity to learn. One of the main problems was it turning out too thick, requiring me to cut a divot in to the galvanometer frame so that the axle would fit in. Second, it didn’t seem as if i was being very efficient in winding, nor could I be consistent with all that messy glue and putting each turn on and pushing it in to place with a screwdriver as the super-glue set. Now, discussion on how I think the winding pattern can be improved.

The current 120 turn winding pattern was this:
I plan on replacing it with a 124 turn coil, of different dimensions like this:

OLD:                      NEW:
0000000000       0 0 0 0 0 0 0
                  0 0 0 0 0 0
0000000000       0 0 0 0 0 0 0
                  0 0 0 0 0 0
0000000000       0 0 0 0 0 0 0
                  0 0 0 0 0 0
0000000000       0 0 0 0 0 0 0
                  0 0 0 0 0 0
0000000000       0 0 0 0 0 0 0
                  0 0 0 0 0 0
0000000000       0 0 0 0 0 0 0
                  0 0 0 0 0 0
0000000000       0 0 0 0 0 0 0
                  0 0 0 0 0 0
0000000000       0 0 0 0 0 0 0
                  0 0 0 0 0 0
0000000000       0 0 0 0 0 0 0
                  0 0 0 0 0 0
0000000000       0 0 0 0 0 0 0

0000000000

0000000000

Silly ASCII art was limiting here–these are actually wider than taller, but you get the picture. The interleaved pattern of 10-9-10-9-etc will make sure it does not exceed the height requirement, as I believe the first one did after slipping in to an offset pattern.

For this coil i used a jig made simply of a piece of basswood cut to the required inside dimensions, and glued it to another base piece, and wrapped the coil around it. It was especially hard at the top of the coil. For the next coils, i have an idea for a jig made of plexiglass and aluminum, that will use an aluminum core, and plexiglass top and bottom–bolted together. This will allow me to use far less glue to hold the coil together during construction, and hard limiting its thickness.

I’m also going to need some better glue– i’m thinking a rubbery kind? not sure yet– hopefully one that gives off less fumes.

I estimate it takes maybe 35 feet of wire to make a single coil. I estimate I have maybe 1 mile of 28awg magnet wire. This means, I should not be in danger of running out due to making this, or the next, practice coil.

P.S. The whole thing turned out to be like slightly less than 2Ω.