I have been using a lot more curves in my work and have been reaching for various devices to help draw those curves. I made a small drawing bow out of maple a while back and I use it pretty often. Lee Valley sent out an advertisement in one of their emails about a fiberglass drawing bow. They were good looking tools, but quite expensive. I thought I could do the same for cheaper.
I started with some fiberglass reinforced plastic. This can go by various names. G10, FR4, Garolite and others. A 1″ wide, 1/8″ thick, 4 foot long piece was 6 bucks from McMaster-Carr. Their shipping is aggressive and expensive, but if you buy a decent pile of stuff, it still comes out to be very affordable. I bought 3 of them.
Lee Valley uses nylon webbing to hold the shape. I had some, but it was 1″ wide also. Something narrower would be nice. I didn’t want to buy anything else, and I didn’t have a good way to attach the webbing to the G10. I went with paracord instead. Not exactly fancy, but it got the job done and I have scads of the stuff around. I drilled a hole and relieved the edge to make sure the paracord stays in place.
The paracord is really slippery and doesn’t like to hold well with typical adjustable knots like the taught line hitch. I printed this little 3 hole tensioner to help with adjusting the bow. Later ones I just used a single hole. It seems to hold well and allows for faster adjustment.
In all I made a 4, 3, and 2 foot drawing bow. This stuff is stiff enough you wouldn’t want to go much shorter, it just doesn’t offer enough curvature. The smallest bow could go tighter if you wanted to, but not a ton. I will need to find thinner or more flexible material if I want to do really tight curves. These make nice subtle shapes and will probably last a lifetime. Go make some!