The Koil Kutter uses a Dremel, and it costs about $70 plus shipping.
I’m considering getting one for myself because I do cut so many
coils. Here’s a tutorial on its use (and the coils look crookedy
after the cut because they move when you take the lid off the cutting
jig).
http://www.members.optusnet.com.au/hamishrodda2/page001.htm
And here’s a couple of old Ganoksin post about how to get the Koil
Kutter and what it does:
Hope that helps.
Sojourner