MIMF

So far all of my acoustic guitar string ramps have been carved square with chisels. Can anyone recommend a good wood file and rasp to provide rounded string ramps.

I usually do those with an in-cantle gouge: the bevel in on the inside of the curve rather than the outside. I got one years ago at a yard sale. It has an offset handle, so that you can push it while making the cut. I surmise that it was made as a pattern makers tool, used to form the fillets on inside corners of wood patterns for metal castings. I inherited another when my violin making teacher died; hers was used to trim the corner blocks of fiddles prior to gluing on the ribs. In either application the tool is being used as a bench chisel would be in cutting a tenon; the chisel lies on the surface with the bevel up and trims anything that sticks up, to make a flat surface. The in-cantle gouge makes short work of rounded string ramps on slot heads, requiring only a little clean up with sandpaper wrapped around a stick. If the explanation is not clear I can try to post a picture.

Twenty some years ago I bought one of these from Woodcraft but don't find it listed any longer on their website.




Looking online I see it's call a Grobet Swiss made pattern file. Coarse and medium cut. I'd say the medium is similar cut to 100 grit. Coarse is more aggressive but still smooth cutting. It's one of my essential tools.

Oops, I was thinking of the string ramp above the nut on a slotted headstock. Nevertheless that Swiss made Grobet is one handy tool. I recently bought a Nicholson "4 in hand" too. It's a squared off version of the Grobet.

Yes, the gouge. Are you using a 1/2 with an #8 sweep?

The 1/2" diameter round rasp looks promising for this application. That is the recommendation from the Cumpiano book.

I'm rasped up. I ordered a 6" hand stitched fine half round modelling rasp, a 6" hand stitched #5 cut half round, and an 8 mm fine cut round rasp. But I'm still interested in a 12 mm #7 sweep incannel gouge so I can be Mr. Edge Tool and smirk at rasps and sanding sticks.