Or you can just use something like this. I make these up with left over wood and use copies of the C&H ignition timing wheels. I make up a bunch and have a few hidden away in my van and when someone is setting up a plane out at the field I loan then one. After that they just have to have one or two of there own, I make them in lefts and rights, for a simple ten dollar bill they can have one!! They really are easy to make and take about an hour with over night setting up of the epoxy.