[Contributed by Ed (etech)]

Part 1

Some of you saw the coil winding machine in my post about rewinding Philco shadowmeters and asked for information on how to build one. I built my machine shown here from plans I received from Gary (Radiofixer).

Winding Machine

Foot Control

Gary has given me permission to distribute his articles on the construction of this machine to those who want them. With that in mind, I asked Ed (Blacksmith) if he would host the files on his server, at least for a short period of time, so that those who wanted them could download them. Ed graciously agreed to host the files. You can find them here.

http://www.renovatedradios.com/

Just click on the downloads page and you will find the articles about the coil winding machine on that page. Then just right click on the files to ‘save as’ to your own computer. The first file is 5.3mb and the second is 3.7mb.

You will notice that the machine I constructed is not exactly the same as the one Gary described, but is effectively the same in principle. I just modified the plans somewhat to use materials that I had on hand or materials that were readily available to me. The heart of the machine is an 18 volt reversible 3/8 variable speed battery operated drill motor. I purchased mine on sale from Harbor Freight for about $14. I took the drill motor apart and mounted it as described in Gary’s article. I made the foot controller by mounting the original trigger controller and battery from the cordless drill motor as you can see in the second photo. In addition, I purchased about $5 worth of hardware to complete the project including the 3/8″ threaded rod that is used as the supply and take-up spindles, as well as the ‘L’ brackets and other nuts, bolts, and washers as needed to complete the project. In all, my actual cash outlay was less than $20 to build the basic machine, provided you have enough wood in your junk collection to complete the box.

You will notice a couple of additional items on my machine which were not on Gary’s original version. One is the addition of a forward reverse switch up on the motor mounting bracket, to allow for easy switching of the rotation. I also needed to find a way to stabilize the reels or bobbins so that they would turn true, since all have different sized center hubs. For this, I found the black wooden balls shown on the take-up spindle in the photo above. I found them in the craft section at Walmart. It was only necessary to drill a 3/8″ hole in them so they could be placed on the spindles. With these, any size center hub will be forced to be centered and run ‘true’ on the the spindles.

With this machine, you can put your wire reel on the supply (lower) spindle, or you can just place your supply reel on the floor between your feet for the unspooling process.

I have used this supplier for magnet wire. http://www.oemwire.com/index.html His prices are reasonable and he carries a good selection. Stripping of the insulation is not required. I just heat the wire with the soldering iron and apply the solder. Within a few seconds, the insulation is burned off, and the wire is tinned.

Rather than build the CMOS turns counter as Gary used in his machine, I purchased the Redington LCD Totalizing Counter from SMC Electronics for $12.50

http://www.smcelectronics.com/emod.htm

and the Door Window Alarm which contains a magnetic reed switch and a magnet for $1.99 from Harbor Freight. I have yet to implement this, but the basic idea is to mount the magnet on the take-up (motor driven) spindle and mount the magnetic reed switch nearby. The switch output will be fed to the LCD counting module to provide a turns counter for the machine. The cost of these additional parts was not included in the materials cost stated above.

LCD Counter and Magnetic Reed Switch

I built and have used my machine primarily for rewinding speaker field coils for some of my radios for which the replacement speakers are either not available, or are quite expensive. I recently used it to rewind a couple Philco shadowmeters. Obviously, there are many other uses for such a machine and I can attest to the fact that the benefits are well worth the time spent constructing it. I would be happy to answer any questions regarding the construction of the machine, if anyone decides to build it.

Part 2

I finally got around to adding the counter to my homebrew coil winding machine. Here a couple of pics.

At first I did some testing to see what it was going to require for the counter to operate. It has a self contained battery which the manufacturer claims has a ten year life span and the power is permanently on. I measured the batteries in the home security alarm and found that they produce only 4 volts, not enough to trigger the counter, since it requires a minimum of 5 volts dc to trigger or reset it. So, I decided to remove the batteries from the home security alarm and use an external 9 volt battery.

I cut the circuit board traces to the magnetic reed switch inside the home security alarm detector and brought out two magnetic reed switch wires through a hole I drilled in the side of the box. I figured the original box would be a good way to mount the magnetic reed switch. It worked just fine. I just used the double sided tape to stick the box to the side wall of the coil winder.

I mounted the magnet assembly to the driven shaft by using the double sided tape supplied by the manufacturer. I decided that the magnet assembly was not secure enough, so I added a couple wraps of electrical tape around it to further secure the magnet assembly. I found the placement of the magnet assembly was not too critical, adjust it for best operation of the magnetic reed switch. I then tested the magnet assembly at the maximum speed of my drive motor, 500 rpm, and it seemed very solid, so I proceeded with the rest of the installation.

As you can see I mounted a 9 volt battery bracket to side wall of the coil winder and routed the wires to the magnetic reed switch and counter in such a way as to not cause any interference to the mechanical operation of the unit.

I mounted the counter to an ‘L’ bracket I found in my junk box and also added a normally open momentary push button switch to the bracket to be used as a counter reset button. I then proceeded to mount the ‘L’ bracket assembly to the side of the coil winder in a spot where it could be easily seen.

A test of the operation of the counter revealed that it would operate properly from a very low speed to the maximum speed of the drive motor. This counter arrangement should be very easy for anyone to duplicate. BTW, I recently saw the same home security alarm that I used in this assembly for 99 cents at my local Dollar Tree store.