MIMF

Has anyone ever made fret roundover files? Pics?

Do you mean a crowning file or an end dressing file? I use the same file for both processes - a small triangular file with an apex ground smooth and rounded. I'd buy a crowning file if they didn't cost so much.

Yes a crowning file. Can I ground a concave in a piece of brass and use emery cloth in the concave cut?

You can give it a try. I think the problems will be trying to squeeze the cloth into such a tight radius, making sure none of it sticks out and scores the fretboard, and then changing it since it won't last long.

You can even make it out of hardwood since it will be protected from wear by the sandpaper. In order to freshen the worn sandpaper just slip it sideways a bit to get a new surface.

I made an abrasive stick once to level shell purfling in the channel of a fiddle. I rounded over the end of a hardwood stick to the correct shape, and used CA to glue on carbide grit from a rock tumbler set. When it got dull and clogged up I just glued on another layer.

I got one of these http://www.stewmac.com/Luthier_Tools/To ... Stick.html and filed a groove in it. I use it with fine girts to polish the frets after I crown them. I guess you could use heavier grits to crown, but it might take a while. I started using a triangular file with one edge filed off to round the fret tops. That worked fine. I graduated to the three-in-one file which worked better. I do enough that it was worth getting the StewMac diamond fret file. But, if I only did it occasionally, the triangular file would be sufficient.

Triangular files were used for many years in the factories. It is important to avoid gouging the fingerboard though, so you need to grind the corners safe and then some. When I reshaped the file I use I had a 6a' sharpening stone on my bench and a junk fingerboard to practice on. The point is to keep grinding off the file teeth near the corner so they don't dig into the fingerboard surface when you lean the file over to get to the upper portions of the frets. The corners become rather parabola shaped rather than round with flat sides (the flat sides being the teeth of the file). Just keep grinding on your stone near the corners of the file and eventually you will have a 'safe' file that will not damage fingerboards but will still easily cut the frets. If your file scratches the fingerboard just grind the edges of the corners. It becomes clear when you are making this happen.

It takes a long session to get a hard file ground down on a sharpening stone, but keep after it and you will be rewarded with a tool you will use for many years. I have been using mine for more than twenty years and it still does the job for crowning frets. It is too easy to grind too much if you use a motorized grinder, and you will be tempted to do so because this process seems to take so long, but it pays off if you make it through the process. And polish the 'safe' corners. They need to be smooth and slick so they do no damage to fingerboards.

Jason Brown wrote:Yes a crowning file. Can I ground a concave in a piece of brass and use emery cloth in the concave cut?

I have done almost exactly that but instead of grinding a concave I just drilled a hole through the brass and then cut the end off through the center of the hole. I then tapered the end as shown. I use wet and dry sand paper to polish the frets after using a crowning file. Just cut a strip the width of the tool and slide it across to bring up new paper after each fret.
The fret board needs to be protected of course and I use those little slotted steel fingerboard guards that Stewmac sells.

I also read an article somewhere by John Gilbert describing how he made fret crowning tools from small sharpening stones.

I make mine from pieces of hard rubber. They are quite a bit like Mick's, but easily made and replaced. You can use rubber squeegees that are made for applying auto body filler, I get them at body shop stores.

If you wish to 'permanently' glue the sandpaper to a form, try contact adhesive or 3M spray adhesive (77, I think). When you need to change it, wet it down with naphtha and the glue will dissolve and any residue can be wiped away.

Double stick tape on the sides of the form works well too as it's easy to peal the paper and shift it an 1/8" over for the next 2 frets or so.

Cant file with edges safed...more flexible than crowning files and holds up well to use. Vintage mando wire is about .040" wide...I usually go with stainless Jescar for these refrets...SM's crowning files are too large to work this wire, but the cant file (a repurposed saw sharpening file) makes fast work of the job. Very old school approach to crowning, but it works for all frets and should be in any pro's tool chest.