I was wondering how do people decide what size drill bit or wire to use to round PE hinges. i find the instruction in the PE sets tend to be too big but when I do them I find that I can roll the flat hinge part into a circle but with too much left over, if that makes sense. So is there away to look at the flat hinge, dfeore rolling, decide what diameter bit or wire I would need to roll it properly?

I usually eyeball it and start smaller than I think it should be. I'd rather start small and work my way up rather than starting to large.

I agree with Scott. it's easier to make the "hole' for the pins larger than it is to try to make it smaller.

Of course, you could just do the math...

Circumferance = pi x Diameter

Circumferance = the length of the PE that will make up the walls of the hinge barrel

Divide by 3.14159 (pi)

Voila, the diameter of the hole you get or the pin you need, theoretically. Of course, nothing ever goes the way it should theoretically, but this will get you into the right ballpark. And the pin should be slightly smaller than the theoretical hole size to allow movement.

Paul