fingerboard shaping tolerances

[peter havriluk]

Just spent a couple of hours (I'm slow when doing something new) using a shaped block to sand a radius into a fingerboard. Made a whole lot of rosewood dust which I saved in a pill jar. Measured the fingerboard thickness at the edges and I'm within a couple of thousandths between them and my straightedge tells me the shaping by sanding looks like it has no low or high spots. The board is just as thick at one end as at the other, measured at the center. Are there generalizations as to what the tolerances of a sanded fingerboard need to be, and how much variability is tolerable? A sanding block ain't a milling machine and a fingerboard ain't a block of aluminum, neither, but I'm guessing that an uneven fingerboard is not a good place to install frets, but I don't have an idea of how even I need to make it.

Thanks very much.

[ken cierp]

I don't want to sound like a "smart a**" here, but this is a guitar not an Indy race car engine. Care has to be taken not to obsess, you are looking for a reasonably straight, level, consistant surface along the length. A few .000's" is not a concern, that would be something viusally undetectable and certainly will not detract from function. The tweaking of a finger-board is done during set-up -- at that point frets are leveled and re-contoured adjusting fret top plane relative to the plane of the strings. Note that as a guitar ages the finger-board surface wears but its not until the frets wear does it become a playability issue.

[peter havriluk]

Ken, thanks for the reasonability comments. They makes sense. The fingerboard I have now, roughsanded to shape with 80-grit and with no low spots that I can find, will get no more attention until after it's glued to the neck and finish sanding commences in place.

A couple of years ago I remember being told the same thing in virtually the same words, but it applied to homebuilt aircraft, 'it's only an airplane, don't get all worried'. Some dimensions ya gotta worry about, and some you don't lose sleep over. Trick is to know which is which and when to worry.

[Dave Bagwill]

" Trick is to know which is which and when to worry"

Peter, ain't no truer words ever been spoken.

[peter havriluk]

Thanks, Dave.

[TonyinNYC]

A wise man once told me, 'You got to know when to hold 'em, and know when to fold 'em. Know when to walk away, and know when to run.'

Well...he told anyone who would listen, not just me. But the point is clear. Sort of. Like Peter said, you have to know which is which and when to worry.
You never count your money when you're sitting at the table.