This is why I ask questions, I didn't even think of that and now it seems like common sense. Thanks. Is there a cheaper one out there than the $60 shipped that I would have to pay LMI for these 3 little pieces of metal? I think it's funny that once you call something a "luthier tool" the freaking price triples. I mean seriously I can buy a 64GB memory card for my digital camera that is WAY more high tech than this tool for about the same price.

I suspect that if millions of people bought gramils the price might come down a bit. You can certainly make your own for much cheaper... I hear they're made from just three little pieces of metal.

The bevel on a gramil blade would affect the cut a bit and that's why you would cut slightly wide and finish with a block plane. But since I wrote my previous response, I, too, came around to thinking of a fine toothed saw. THIS ASSUMES THAT THE SIDES ARE NOT YET GLUED TO THE END BLOCKS. It also assumes you have a band saw.

I'd rest a side on its bouts and measure the height of the waist above the resting surface. I'd make a temporary fence a bit higher than that. I'd clamp the fence to my bandsaw just proud of my desired cut line. With a fine toothed blade on the saw and properly tensioned, I would hold the side as flat as possible to the table--starting with the neck end flat to the table and the tail end in the air, rotating the side as I progressed until both bouts were on the table. Carefully keeping the side against the fence, I'd advance it slowly through the waist area until the blade was engaging the lower bout. Then I'd rotate the neck end gradually UP, keeping the side stock on the table until the blade exited the heel end. Of course, I'd pay close attention to where my fingers were located at all times. You could use the band saw to make a support for the waist area, too. Tape it to the side just outside the cut line.

You can make a woodworker's cutting gauge from a marking gauge by screwing a blade to the end of the beam. As had been said, cut from the inside and outside until the cuts meet. Cut with the bevel away from the narrow binding piece, that way the piece is essentially done when the cut is complete and you can use a plane to clean up the larger piece ready for the next cut if needed.

Why not do this before the side is bent?

Ed

You make it sound difficult. It's a very straightforward task that requires little in the way of tooling.

Sounds to me like your original end mill trick ought to work out well. The cool thing about doing it this way is that now your bindings are bent perfectly. If you have a drum sander it would be easy to thickness the bindings perfectly.