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I have thicknessed, slotted, and tapered the fretboard for my first guitar. The underside of the fretboard from the 12th fret to the soundhole needs to be relieved to match the contour of the slightly arched top.
My books call for hand planing the ebony fretboard, but I'm not very confident about my skill, so can I achieve the same result by dragging a sheet of sandpaper between the guitar top and the fretboard?
I have used this technique in many other woodworking joint fitting operations.

Thanks,

Ray

seems to me like thats a whole lot of ebony to remove just by sanding.
perhaps doable but i'd guess its both laborous and very patience-wise challenging.
perhaps you could make a cardboard template of the break angle,transfer it unto the FB and than rasp it down or grind it on a belt sander...?
with my guitars i know that neck angle i'm gonna end up with and ive built a small jig that enabels me to cut that same angle into the FB on the table saw.

Ray,
The variable angle jig shown here works great for this purpose. It doesn't have to be fancy. You just need a board on a hinge and something on which a router can ride horizontally. In fact, I developed an earlier version of the one shown specifically for what you need to do. It was only later that I realized the concept would also work well for elevated fingerboards/necks.

Another way is to make a quick router jig to invert the fret board at the desired angle and route off the board.  I think there is a jig mentioned in another thread.

BTW your instrument is stunning!  I hope to do as well.

_________________
Steve Walden
Aspiring Builder,
Bartlesville, OK

I also might suggest the Wagner power planer in a drill press option.  Again there is a thread in the archives on that.

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Steve Walden
Aspiring Builder,
Bartlesville, OK

Sanding isn't so bad, but I would not drag the paper between the top and the fingerboard. I glue very course sandpaper to one end of a long piece of flat wood or particle board and lay that on the table. Then I tape a shim to the underside of the fingerboard near the nut to get the desired angle.   I slide the fingerboard over the the sandpaper with pressure near the end that is to be sanded. It really goes guite fast and is perhaps easier for a first guitar, where the builder may not have developed tool skills, yet.

Sorry to 'go against the grain' here, but.....
I think you'd be farther ahead to spend an afternoon (or even a whole day) to get your plane sharp and do some practice on scrap wood. Develop a bit of skill and you will be able to do this job (tapering FB underside) in a few minutes using a plane. It is not that difficult to do.
Also, once you have your plane sharp, you will be able to level the FB, tapering the bass side if necessary(after gluing and before fretting). It's a lot more accurate than trying to do everything with sandpaper, rasps, etc etc.
You'll never regret developing more woodworking skills. Anyway, isn't that the point? If you just want a guitar, it's a *lot* cheaper to just buy one.

BTW- I concur with the advice against dragging sandpaper between the top and FB, for another reason as well. It's difficult to avoid loose bits of grit getting under the smooth side of the paper and scratching the 'good' surface. I've had to learn to be very careful about this when fitting necks to sides by 'flossing'.

Also, contrary to some advice you may get, it's not necessary to have a very expensive plane to do this sort of job. Take what you've got and get it sharp and properly adjusted.

Cheers
John

I agree - learn how to use a plane for this.

but if you happen to have a Safe-T-Planer it makes quick work of it... just shim the underside (fretted side) at the 19th fret and take light passes adding shims until it fits good, then scrape it.

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Instagram: @jfrenchluthier
Web: https://www.jfrenchguitars.com/

Yes, planing skills are good, but I cheat and use the Wagner. I have a jig that is two boards hinged together with a slot for a shim to spread them apart to form a wedge with the desired angle. The fretboard gets double side taped to the wedge, a heavy line is marked across where the 12th fret is, and then the board is passed under the planer until material is removed back to the 12th fret line.

I'm trying to write up the math to do both the relief from the 12th to 19h fret and a full length taper with the shims worked out in advance, but I don't have it all cleaned up yet (and tested to my satisfaction).

Jim

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Jim Kirby
kirby@udel.edu

Hey Ray,

I'm inclined to agree with John and Joshua here. Planing it off a bit at a time will likely be the quickest and most accurate way to accomplish this.

But I would like to make a comment about building a classical with an arch up in the fretboard area to begin with. To my knowledge, this generally isn't done -- for just this reason. The soundboard and the underside of the fingerboard are both flat in this area, which allows for easier fit-up. I build all my classicals with a flat upper bout.

Best,

Michael

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Live to Play, Play to Live

Yeah, but even with a flat upper bout, if the neck has the normal 2 -3 mm negative slope to the nut end, it would still create an angle when you apply the fingerboard.  Not much of one, but an angle non the less.

_________________
Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

Thanks to all. I took John's advice and sharpened my block plane and started practicing on a Walnut/Poplar leftover piece from an IncraJig project.
In no time at all, I am getting pretty good results.
I will make a few more trials on scrap hardwood, then re-sharpen and give the ebony a try.

Thanks again to all,

Ray

[QUOTE=WaddyT] Yeah, but even with a flat upper bout, if the neck has the normal 2 -3 mm negative slope to the nut end, it would still create an angle when you apply the fingerboard. Not much of one, but an angle non the less.
[/QUOTE]

The negative slope is not necessary on a classical. I began building classicals using Cumpiano's method, and still do most of the assembly the way he outlines in his book. Cumpiano builds his classicals with no negative slope, and so do I. Based on my own results, I really don't see the point in it.

Best,

Michael

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Live to Play, Play to Live

Michael - If you have no negative slope, do you have to compensate by tapering the fretboard? My understanding (possibly flawed) is that Torres and a lot of early 20th century guitars have no forward set, but tapered fretboards.

On the other hand, a friend of mine has a Raya Pardo, which I gather is fairly typical of the modern Granada instrument, that has a LOT of forward set (I estimated 4mm or a tad more) and no fretboard taper.

_________________
Jim Kirby
kirby@udel.edu

Way to go, Ray!
Shavings, not sawdust!


Cheers
John (owner/user of many sanders)

[QUOTE=jtkirby] Michael - If you have no negative slope, do you have to compensate by tapering the fretboard? My understanding (possibly flawed) is that Torres and a lot of early 20th century guitars have no forward set, but tapered fretboards.[/QUOTE]

Yes, I taper the fingerboard -- on the bass side, although not to the extreme that some other builders have -- most notably Jose Ramirez during the 60s and 70s.

Best,

Michael

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Live to Play, Play to Live