Intro: How to Make Conductive Thread
This thread consists of very fine wire and thread combined together to create the strong, low resistance thread.
The actual process of making the conductive thread is quick and simple...
It is the tool needed to make the thread that can take the most time. Once the tool is finished the thread production takes relatively no time at all.
Step 1: Materials Required
In order to make this type of thread you will need the following:
1: 2 feet 1x4 cut into 3 pieces, 1-1 foot and 2 - 6 inch
2: 30 inches of 5/8 copper tubing (feel free to substitute)
3: stiff wire coat hanger or 5/16 brass dowel
4: Magic Bullet (tv blender) shaker lid or plastic salt shaker lid
5: 8 small circuit relays or very fine magnet wire.
6: fine cotton thread
7: 10 5/8 id washers
8: 2 fender washers
9: 1/2 inch sheet metal screws.
2: small hammer:
3: small flat screwdriver
4: small wire cutters.
5: Dremel tool with cut-off wheel or drill press.
6: tubing bender
7: Hot glue gun
Step 2: Build the Machine Base
The machine is required to combine the cotton thread and wires into the final conductive thread.
The 1/4 are screwed together at the ends into the basic C shape as shown in the first picture. The shape of this is not critical but this configuration works for me.
On one of the upright sections you will need to add 8 pegs for the spools of wire to hang on. This was done by measuring 1 inch spaces and drilling a 1/8 inch pilot hole. The upright hangers are 5/8 brass dowel but still coat hanger will work as well. These were cut at 2 inch lengths and tapped in with a hammer. 8 washers are needed for a bearing surface and these hang one on each peg next to the wood.
The top center hanger is for the thread and is just a 3 inch wood screw with a fender washer for bearing surface.
Step 3: Build the Machine Crank
This machine requires a hand crank with an optional spooler for winding the conductive thread.
1: The Magic Bullet shaker top is mounted to the base of the machine at 2 inches from one end by first drilling a hole in one edge the using a 1.5 inch wood screw to fasten. I used one of the relay covers (will explain next step) as a spacer. The mounting points were hot glued to maintain their alignment.
2: There is a eyelet guide needed and this was made by wrapping a piece of bare copper wire (household electrical grounding wire) around a 5/8 inch drill bit. The center of the eyelet aligns with the center hole in the shaker top. The base of the eyelet is screwed to the machine base using a short sheet metal screw.
3: Next you will need to drill a 5/8 hole in the opposite machine upright. It is critical that it aligns with the center of the shaker top.
4: Through this hole you will feed a 10 inch piece of the copper tubing. I flared the end with a special tool to prevent the sharp edge of the tubing from damaging the thread (picture 5). The washer that you see on the tubing in the 3rd and 4th pictures are to create a bearing surface and provide a stable cranking motion.
5: Using a tubing bender I bent a 'Z' Shape in the tubing to create the crank. The measurements are not critical but I left enough room to allow the machine to be placed flat on a bench and still be cranked.
6: The opposite end of the tubing was also flared for sharp edge removal.
7: The crank is then pulled snug and wrapped with electrical tape by fastening one end to the tubing and spinning the crank. Enough tape must be used to provide a secure and stable crank.
8: The spooler was made by making a j bend in the tubing using the tubing bender. The bend must be such that it make the j align with the center of the shaker lid. The other end was flatened in a vise and drilled with 2 holes.
9: The flat part of the spooler is screwed tot he base using 2 sheet metal screws and the other fender washer is attached to the 'J" bend using hot glue. This provides a limit for the spool.
Step 4: Harvesting the Magnet Wire
I could not find any suitable very fine magnet wire locally so I came up with an alternate source.
I had several small relays that I recovered from damaged circuit boards, I opened one to find that the coil has exactly what I was looking for.
These Omron G5LE series(can be found at Digikey for about $2 each, should you need to buy them) relays have a cap that is easily removed by lightly prying with a screwdriver. I used one of these caps for the wire guide support on the machine in the previous step. ( it was drilled with a small hole end to end for this purpose).
On the top of the relay there is metal flap and formed spring this cap was pried up using my fingers to reveal the center core of the coil.
This center core needs to be removed, A drill press will work but a much faster and reliable route is to grind the end off using a Dremel tool with a cutting disk. Just take the head off and the shaft can be driven out with a small screwdriver and a light tap.
Remove all of the metal tabs by pulling them straight out of the plastic base.
You will now be left with a roll of very fine wire on a small spool.
This is repeated 7 more times.
Step 5: Load the Machine
1: The spool of cotton thread is placed on the top hanger and the thread is fed through the center hole of the wire guide ( shaker top) and then through the eyelet.
2: I started at the bottom left an placed one wire spool on the lower peg and fed the fine wire through the lower left hole in the wire guide then through the eyelet. The wire is gently pulled and if there is any binding then the plastic wire spool may need to be trimmed with small wire cutters.
2:a:This process was repeated until all holders were full and all 8 holes in the wire guide were used. You should now have an unformed 8 wire assembly with a cotton thread core.
3: In order to feed the uncompleted thread through the crank handle you will need a piece of fine still wire to act as a fish. Simply push it through and attach the end to the thread assembly and gently pull it all the way through the crank and remove the fish wire.
4: If you hold the loose end to the crank ans begin spinning the crank you will see the wire and thread spin together. The goal here is to get between 6 and 12 turns per inch. once this has been achieved you can begin winding the thread onto the spooler.
NOTE: I ended up not using the spooler since I could not get the desired turns per inch and I only needed a short run of thread.
5: The spooler is first wrapped with a piece of paper to allow for easy removal later. The end of the completed thread is fastened to the paper using a small piece of tape. Since every turn of the crank produces only one twist on the wire you will need to pinch the uncompleted thread lightly with your fingers relatively close to the crank inlet side this will prevent the twist from being distributed over too great of distance.
6: You will have to experiment with the pinch to produce the optimum results.
Step 6: The Completed Thread
The finished product is essentially an 8 conductor cable with a cotton thread core. This configuration provides flexibility and strength.
This thread is still remarkably thin and can be threaded through a standard needle. I have not tried machine sewing with it as of yet.
The best part is that the thread is insulated since the conductors are magnet wire.
In order to be conductive the coating needs to be removed and this can be done by heating it with a soldering iron at the desired connection point A little solder ball on the iron helps greatly. This coating is nylon and stinks like burned electronics when melted off. This is why you use cotton thread, the poly thread will burn away and greatly weaken the structure.
Alternately you can rub the thread with a very fine sand paper to remove the coating at the various points where continuity is desired.
As you can see in the pictures The coated thread is insulated and does not conduct even when the meter leads are place close together.
The final picture shows that a 1.5 meter length of thread with solder ends only has 1.9 Ohms resistance