Hi Nomeous,
The first flat bow I made was out of a hickory stretcher pole, that broke as it was too dry. The second, third, fourth, and fifth, I made out of two pickax handles joined at the middle by a box joint as the bow did not bend through the handle. You must back the bow with either sinew, linen, silk. or plant fibers for safety and make sure it has a moisture content of 10% to 12% before you start work. Having said that, I still have, and shoot my pickax handle bows frequently. I designed them specifically for speed shooting and that means a lot of work in the limbs. Make sure when you select your limbs (two pickax oval sectioned handles) that the grain matches as closely as possible and runs across the widest part of the handle right through to the nock end, and keep your limbs as wide as possible and rectangular. When you come to tiller keep your desired weight, say 60#, the same at each increment, I.E. 60#@15", 60#@ 20", and so on until you reach your desired draw length. I am assuming you are using a wall tiller board and pulley system.
My pickax handle bows work well for me, and there is no sign of stress as yet, although they follow the string slightly. If you keep to the 64" or higher length between nocks rule you should decrease the string follow. I like a little string follow as the bows are not so sensitive and don't jump too much in the hand. I shoot off the hand and not off a shelf, so you must make sure if you do, that your arrow spine is perfect. My draw length is 27.3/4" and my arrow diameter is 5/16" My bows are all between 60# to 65# so it is possible to make a good bow out of pickax handles. I use Araldite two-part 24hr glue for the handle, cured in a incandecent bulb heat box with thermometer (handle section only) at 100%, turn the bulbs on and off to regulate the temp, and waterproof PVA glue to soak the back of the bow and fabric in before backing, unless it is sinew. I hope this helps. Good luck Johno.
