The Bow

If you ever done any pattern drafting you would often find yourself drawing curves. The hemline of a skirt is a typical example. For small curves a French ruler or a compass would do just fine. But what if you need to make a big curve, let's say with a radius of a meter or more?

Ladies and gentlemen, please let me introduce you to "The Bow":

The immediate reaction I get when showing this to people is "what IS that thing?"
Well, let's take a closer look:

This is just a long, flat piece of metal. In one end there is a hole with a cord pulled through. In the other end it's the same, except there is also a cord lock attached.

The more interesting part is what it does.
By pulling the cord you can adjust the bow into large or small curves. You can then use it as a ruler for drawing.

Making one yourself

You need a long and thin metal bar with a decent length. The one I got is 1m long, 1cm wide and 2mm thick.
A strong and thin cord is needed for this. An accessory cord is perfect. That's the kind of cord climbers and hikers use. Both items can be found on most hardware stores. You can also find accessory cords in sports stores, outdoor shops and army shops.

Drill a small hole about 5mm from each end, and smooth them with sandpaper. The hole should be as small as possible, but just big enough to get the cord through. Put in the cord, insert cord lock, make knots. Done!

Note: this bow have some limitations:
The smaller the curve (the more you tighten the bow) the less even is the curve. The more you tighten it the more it will turn into ellipse rather than circle. For big curves however (when you only tighten the bow a little) the curve is very even. You'll mostly be using it to make big, moderate curves anyway so it's not quite a problem.