"vdubbs" wrote in message
ups.com...


I don't follow you on why it would not work. If the wheel follows the
surface and fits around the pencil, then the pencil would be held
parrallel to the surface you are needing to fit too. As long as the
pencil stayed perpendicular to the surface you are scribing on, you
should get a very close fit as long as you allow for any inside
corners.

BTW, I pretty much failed geometry, so feel free to correct my error on
this as I don't see where the problem is except for the price.

Take as an example a semi-circle. Run the wheel round the inside of the semi
circle and the copy will be parallel, but the new semicircle will be smaller
by radius of the wheel. Try it, like I did, with a pencil and a washer.