Hi List, I'm working on a plate from a 1926 Steinway M that had been breaking lots of string along the capo.  Both sections broke about the same number of strings per semester.  Upon pulling the plate and looking carefully at both sections, the top section was really flat (plus grooved and crusty) and the lower section was more pointed like we like, but way deeper grooved (and just as crusty). So, my conclusion is that both too deep of string groove and too flat a capo surface experience the same amount of string breakage. Now, I can't remember the width of the "peak" of the capo, but seem to think along the lines of 0.5mm-1.0mm (top to bottom of whole capo)  Is this a bit too sharp? Could someone please remind me the proper "shape" before I begin filing?  Do all the string grooves need to be gone? Thanks for the input! Paul