Intro: Jumpwire Jig
I am embarking on building an LED Matrix that is going to require a few hundred strands of 4" jump wire, and I really didn't want to measure and cut all of those wires. I decided to make this jig that would give a roughly accurate wire length, and allow me to cut down the time I spent measuring and snipping wires.
Stay tuned for a wire stripping jig....
Step 1: Cut Down Stock
I grabbed some 1" mild steel square channel stock from the scrap bin, and cut a 6" piece with the cold saw.
When using a cold saw it is important to properly vice your work. Steel requires a lower cutting speed than aluminum would require, so be sure to check the cut settings on the saw before you begin your cut. Once there was coolant running through the blade, I slowly pulled the saw through the square stock.
Step 2: Mill the Part
Here at the Instructables/Autodesk workshop at Pier 9, we have an awesome metalshop with a Bridgeport Mill. Using a 3/8" end mill and collet, I was able to make several passes and mill a channel out of the square stock.
I set the square stock on 7/8" parallel bars in the vice, then raised the bed of the mill up to the end mill. I only had to lower the quill a little bit.
I set a spindle speed of a little less than 1200 based on the the spindle speed equation: (SFPM x 4)/diameter of end mill. That ends up being (110x4)/.375=1175ish RPM - In High Gear/High Frequency I began to mill my part.
I made 5 passes with the mill, sinking the end mill into the material about 30/1000s of an inch with each pass.
Step 3: Finished Part
I deburred the edges of the jig with a metal file, and then threw it in a sandblaster to get all of the tool oils off of the part. Sandblasting also took off all of the printed material info from the square stock, and left me with a perfectly frosted Jumpwire Jig.
Step 4: Wind the Jig
I used a little bit of electrical tape to secure some solid core wire to the edge of the jig, and then began to wind wire around the jig. I got about 50 turns on the jig before I had filled it.
When I reached the other end, I taped down all the other end to the jig.
Step 5: Tape and Snip!
I was nervous about the wires coming loose as I snipped them away, so I secured them all with masking tape that would be easy to remove. After taping the sides of the jig that I wouldn't be cutting, I began to snip my wires.
Moving across the channel I had just milled, I slowly snipped all the turns on the jig. I was left with perfectly uniform length wires. I repeated this process three times, and it worked great.