Local feral survivors in eight frame medium boxes.
I have not tried it. If I was to try it I would by a very fine toothed plywood blade and put it in backwards.
A low angle block plane worked great and is much quicker than I thought. The current PF-120 top bar is 1" wide so shaving 1/16" off each side of the end bars leaves a full 1/4" bee space between the top bars while providing 1 1/4" spacing. Here is a photo of nine PF-120 frames in a Rossman 8-frame commercial cypress box.I use a low angle block plane and shave them down by hand. Doesn't take as long as one might think. With a sharp blade the plastic cuts like butter.
Band saw ??? I like better Michaels Bush's idea better but why not try both, You are risking only one frame per idea.I'm planning to see how my band saw can tackle this issue. If that doesn't work, I think my best bet would be to try Michael Bush's suggestion and turn my carbide tipped blade around backwards in my table saw and try that.
I have not pursued this any further since I began this thread, but I continue to contemplate it quite frequently (I still have several full-size hives where the frames/combs are crowded too tightly between their vertical slatted racks). I appreciate the updated information about the top bars being only 1" wide, I hadn't realized that, so after trimming the end bars they still have an eight of an inch of clearance between their trimmed end bars and top bars (1/4" total clearance between the top bars of adjacent frames).A low angle block plane worked great and is much quicker than I thought. The current PF-120 top bar is 1" wide so shaving 1/8" off each side of the end bars leaves a full 1/4" bee space between the top bars. Here is a photo of nine PF-120 frames in a Rossman 8-frame commercial cypress box.