Hi all,
After 8 months of daily use (1-2 hrs a day), the 1st 5 frets on my learner mando, an A-style Santa Rosa, were grooved deep enough to affect intonation, particularly on the A strings. The grooves were worst on 2-5 and only under the unwound strings. Assesing the job ahead, I looked at the Frets.com articles and checked this forum finding lots of good tips. I had always thought the frets looked a litle concave to my eyes, but after removing the strings and checking with a straigtedge perpendicular to the neck found that both the frets and the fingerboard had a slight but noticable negative radius. Is this common? I assumed that this was a a manufacturing defect resulting from exessive clamp pressure, cupped wood, or a poorly prepared neck surface.
Long story short my fret leveling and dressing fixed the intonation issues and made the upper fretted notes sound much better as well...but I couldn't bring myself to go with a negative radius sanding block to achieve the leveling, thus the fret ends now have less height above the board than the center of the frets. This will reduce the number of fret dressings that can be performed of course. I'm pleased with the intonation and the new smoother feel of the neck...but should I have maintained the concave radius?
Also, I used an alternative to a fret crowning file found here on the forum. Drilled a hole through a block of wood (for my frets, a 1/16 drill bit looked a good match to the fret crowns), split the block along the drill hole (ok this was a tedious process in oak using an x-acto saw) and used 400 grit sandpaper to line the hole in one block half and stroked each fret 30-40 strokes. Results were not quite as domed a profile as I would have liked to see, but after polishing th frets with 0000 steel wool, the old beater sounds better than it has in weeks. The new J74s helped too.
Scott
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