Easy to make and very handy to have on hand, it lets you draw curves and arcs of almost any radius. It’s made with a strip of clear, straight grained hardwood, cut to about 1/8″ thick. A string is used to bend and hold it at the desired curve:

One end has a slot cut for the string to go through:

The string loops over a piece of wood with a hole drilled through. This simple mechanism clamps the string in place, after the curve is set.

Two notches hold the string in place on the other side:

This bow produces symmetrical curves. To create a bow for asymmetrical curves, the strip would be planned thinner on one end – a straight taper of 1/8″ to 1/16″, for example. The bow will bend into a tighter curve on the thinner end.