Pictured here are three crossbow strings. In Green on the left, a commercially available heavy duty dacon string. You can buy these from amazon or any good outdoor sports centre and this will draw over 150lbs and made from 33 strands.
In Yellow on the right is my "get it done" bowstring, made from cheap poly cord. It was really a tools and technique practice on the flemish twist loop and winding. You can see the binding is a little scruffy, but this is perfectly serviceable at a low draw weight. It's about 3/4" too long, for lack of experience in how much slack it needs, and there are only six thick strands. I used this to test a synthetic prod, and around 70lbs the prod buckled because the shape was uneven and I've reasonable confidence you could push this up to 100lbs without it breaking. I think it'd fray easily and isn't ideal but it was a good trial run.
In the middle made from white dacron is my first attempt at a "real" string. It's a hand-wound flemish twist, made from 26 stands of 30lb line. It's still a little scruffy and my technique could be improved a little, but it holds strong and should be more than strong enough for a 100lb bow. It feels really solid, took a few goes to get right, but represents most of the tools and talent to get the job done.
After a few failed attempts I watched a couple of videos of this being done, and they don't half make it look easy. With practice you can hold the line in your hands, but for the rest of us there is no shame in using an extra clamp or two so you can focus on the bit you are working.
In fact, I'm considering a jig containing a couple of clamps on an axle. The jig has a two-fold benefit here, firstly in just giving you more control, and secondly my real limiting factor was that my hands cramped up from gripping and twisting the string. I'm sure with practice and experience you'd be able to make your own string quickly as part of a one-day-build crossbow, but for me I had to wind in short bursts and stretch out. A jig prepared in advance should make this pretty easy.
The second tip is to add beeswax to your fibres to bind them together. This gives you more control of the string as you manipulate it. Neither of my two efforts pictured above were waxed, but you can feel the green professional bowstring is waxy and it's something I've been experimenting with since.
There is another method for making strings called a continuous loop, which appears to be made out of a single long loop, and then wound and bound. To make this, a simple jig with the correct spacing for the length should be enough. I'm going to guess it's less traditional than the flemish twist but seems to require less tools and talent.
I'll report in with pics of the next few strings and then move on to prods and the furniture.
