Single edge razor blades are better for making long cuts in styrene, but they are impossible to hold by hand. I made an inexpensive holder that makes it easy. Just google "S.E.R.B. holder mod 1"
Gary, the Google search did not work very well. Just copy the hyperlink and then use the hyperlink insertion tool in the header of a new post dialog box (the chain link icon) to insert the link in a post. You could just edit your original post, wipe across the "S.E.R.B. holder mode 1" text and then click the link icon and paste the hyperlink in the URL box.
The holes could be drilled with a #43 bit and then tapped with 4-40 threads for the screws, eliminating the nuts.