# Wire increasing in width

I have been using my brand new durston 100mm combination rolling mill to draw wire. I have been told that wire decreases in thickness, increases in length and that it’s width remains the same. However I find it’s width does increase not by much but by enough to make it noticeable, about half a millimetre. This does not sound like a lot but when I want to make, say 4 mm by 2 mm rectangle stock and end up instead with 4.5 mm by 2 mm rectangle stock I am upset. What Ann i doing wrong?

Do you turn a 1/4 turn after each pass? I keep records of before and after dimension and then use a simple proportional calculation to repeat the results for different lengths. It takes time to collect this data. You can also go to the hardware store and buy various gauges of solid copper wire and experiment with it.

I did lots of experiments some years ago and created a graph of of wire width to thickness for various thicknesses. From that graph I devised some equations and then created a program that I use for determining what size round or square wire I need to create strip of a particular width and thickness.
I’ve made this program available at the following URL Rolling
You specify what width, thickness, (and optionally, length) of wire you want, and it tells you what sized round or square wire you should start with. If you specified a length, it tells you what length to start with.
Normally you don’t have the required size in stock, so you just say what you have and then roll that down to the starting size, then roll the strip.
Works for me.

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Sounds amazing thank you so much for sharing

Thanks, so far I have tried just rolling the square stock 0.7 or 0.8 thinner before milling it down to rectangle (or half round) it works pretty well. I will have to try your way.

Thank you for this. Very helpful.