Router Jig for Radiused Fretboards

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saltytri

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OK, I know that not everyone thinks that radiused fretboards are worth the time and trouble that it takes to make them. Maybe, maybe not. At a minimum, I have a lot of sympathy for people like me who have some degree of hand dysfunction and who feel that a radiused board is helpful, particularly with barre chords. At any rate, I've been making them by sanding the radius by hand with concave blocks. This works but I wanted an easier and quicker method so this jig was the result. The board is attached to the central spine with double stick tape and the router slides both laterally and longitudinally. The amount of hand sanding that it takes to finish the job is minimal. As the Brits say, "It works a treat!"

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This a beautifully built jig. I've just spent 10 minutes trying to figure out how it works and then I realized I could never pull something like that off. Beyond my wood chops. But I get the basic idea. Also this method could be used to radius blocks and even back braces maybe. Nice work.

Just one question: How did you cut out the radius guide to begin with? In other words, how did you make the jig that made the jig?
 
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I already had this swinging beam fixture to make nuts and saddles to match the radius of the fretboard using the oscillating belt sander. The cross arm was added to support the long pieces used for the convex curved guides. These were first cut close to the correct curve on the bandsaw and then swung across the belt sander to get the radius just right. These convex pieces were then used to mark the curves for the concave runners, which were then roughed on the bandsaw and refined on the oscillating drum that you can see to the rear of the belt sander. Then strips of self adhesive sandpaper were put on the convex pieces and the concave pieces were scrubbed back and forth until they matched nicely.

CA was wiped over the surfaces and sanded to make harder bearing surfaces so that things would slide smoothly. Also, there are polished acetal plastic pads under the cross pieces so that the whole assembly slides easily along the central spine.

I hope that I live long enough to be able to say that the hours of work that this took will eventually be justified by the time saved by not having to sand each board to shape by hand. :rolleyes:

Anyone want to buy some slightly used StewMac radius sanding blocks?

http://www.stewmac.com/Luthier_Tools/Tools_by_Job/Tools_for_Sanding/8_Radius_Blocks.html
 
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That's such a smart idea! Radiusing guitar fretboards with the blocks is 25 minutes of the most strenuous labor a luthier has to do. I get tool envy every time I see one of those belt sanders that sits on its side. I'd probably finish all the curved edges with a Robo Sander on the drill press. I wonder if routing a pre-slotted board would cause a lot of chip out?
 
Thanks, John! Of course, this was copied and adapted from someone else's jig, which was probably copied and adapted from an earlier version. You know how that goes. :)

That sander sees a lot of duty and makes short work of a lot of little jobs. It's a really useful tool.

Good question about chip out. I used to cut slots on a table saw carriage that requires that the board be flat when slotted and then radiused later. Lately, I've been slotting with a CNC router. It doesn't care if the board is flat or radiused so I can avoid the chip out issue by doing the radius first.

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Slotting with the CNC has the additional advantage of avoiding exposed fret ends, at the cost of doing a lot of tang removal. The boards can be bound or not. If not, I think of them as "faux bound."

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Michael N. said:
Sanding that amount is probably strenuous. Planing with a block plane isn't, in fact it's easy and a lot less dusty.
Click to expand...

I'm sure you're right, Michael. I could also rough them in on the belt sander to save a some time and effort. These days I radius so few fingerboards that I just tape them to my saw table and have at them with sanding blocks.

A low-angle block plane might be a worthy addition to my shop, but I haven't used my other planes in decades and they aren't part of my thought process. In my shop planes are obsolete and generally useless.
 
Nice, -The best tool i've seen (this is second best btw) is by John Greven who uses an electric planer with a bit/planer blade he had custom ground to a radius- one swipe and its done!

 
That take the prize for cool! I'll be happy coming in second to John Greven any day.
 
My guess (and it is a guess) is that you need very well behaved wood for that to work. Switching grain might prove somewhat problematic?
His fretboard slotting method looks somewhat dangerous.
 
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That's exactly how I slot my fretboards, with a sliding miter saw. But, the guard is on mine and I still shut the saw off when I move the template.
Works great and it's fast and accurate
 
Michael N. said:
My guess (and it is a guess) is that you need very well behaved wood for that to work. Switching grain might prove somewhat problematic?
His fretboard slotting method looks somewhat dangerous.
Click to expand...

I agree with Michael. That left hand postilion made me feel a little queasy. Jumping tools happen and I seen it and have the discolored underwear to prove it. However, I really like the idea and with some more rails and clamps where you could get behind the tool, this is a very interesting and workable idea. Very slick and very fast, but knots and dull blades happen and things could get out of control very quickly and that would not be fun.
 
Of course, he's built over 2000 guitars so he seems to have it under control. ;)
 
No one is suggesting that it doesn't work but there is a safer working method. It only takes one distraction at the wrong time. No one in industry would get away with using a machine in such a manner. Of course you are free to use whatever dangerous practices you wish - providing it's just on yourself.
 
The problem with cutting the slots from above like that, means you have to make the fretboards all the same exact thickness ,otherwise you get varying depth of slots.
 
Maybe he uses shims underneath to compensate for different thicknesses.
 
saltytri, that jig is one of the coolest things I've seen in a long while! Once I've sold a couple of instruments and have some extra cash, I am definitely going to make something like that for myself. Thank you so much for sharing this!
 
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