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In another thread on end mill bits, Tim Mullin pointed to a site called precisionbits. While there, I stumbled across this.

http://www.precisionbits.com/guitar-fre ... 13006.html

Anyone have any experience with them?

Thanks in advance

Steve

I bought a similar bit from another supplier expecting that it would make the radiusing job much easier. It grabbed the grain of the first board I fed to it and tore the fingerboard in the middle. (I had the board attached to a stout hold board with double-sided tape.) I decided not to do that again. I went back to the track guided router method.

I saw an advertisement for this https://www.luthiersuppliers.com/lsprod ... radius-jig and made one for 16”. I like it better than any of the methods I have tried so far (including having LMI radius the board for me). If you decide to go with that jig, I recommend that you just buy if from Luther Suppliers. I spent way too much time making one.

I also bought a similar bit, looks identical, from another supplier. I tried a bunch to get it to work. Very inconsistent results. I would not recommend this method. The Luthiers Supply one looks interesting, but it would not last long here in Hawaii. MDF just disintegrates here.

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

I really want to machine that jig in aluminum.

Seems that a CNC router could be used on aluminum vs a full-blown cnc mill. Just need to draw it up and find a friend with a router...

I never had any luck with those.
I had a custom set made to put in a planer and it also gave less than good results. I use a jig in my thickness sander

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I bought one of those bits, and although I haven't tested it out extensively, the board I radiused with it turned out O.K.. I just did a quick set up using a less than ideal fence and hot melting the work piece to a scrap of particle board. I took small bites with the router which I think is key to not putting pressure on the bit (causing it to chatter). With better jigging I think an acceptable result could be had. It went relatively quickly.

I use the ones made by sje tools. I think they were earlier to market. https://sje-tools.com/. I use them in 16", 20" and 24" radiuses. I really like them You need to be able to tape them to something to hold the fretboard flat They suggested a aluminium angle bar. I leave at least the thickness of the bearing un routed and finish by hand with a radius block. I probably done a dozen fretboard. It beats the other ways that I have done them.

The only real negative is that I need to radius an unslotted fret board or i get tear out. To deal with this and still have flat planes to work with while fretting I leave and area on both sides of the fretboard blank not radiused.

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http://www.Harvestmoonguitars.com

"I leave at least the thickness of the bearing un routed "

+1 (although sometimes a little less, if I'm feeling lucky)

I finish them off with a 2 ft level with sandpaper glued to the edge, sanding along the string paths.

I put a lot of energy into fingerboard radiusing jig ideas, but then I came to the conclusion that I was better off using hand planes, radiused sanding blocks and leveling beams to get the results I want. I think fingerboards benefit from slower, more precise shaping methods. If you need to generate a lot of fingerboards, then tooling up is better. But for hand builders, I think lower tech is actually more efficient. YMMV.

Luthiers' love of jigs are because they want to improve repeatability and precision. Most of the fingerboard radiusing tools and jigs are not perfect, but they get you close and give you a baseline to work from. I think most of us look at them as a way to "rough out" the board and not the finished product. There is a balance between tooling and handwork, and finding that balance is a personal thing. I prefer to do the bulk of the work as efficiently as possible and then spend the time doing handwork where it counts. I prefer simple jigs and tooling that is quick to set up and use and I am willing to sacrifice some effort to handwork because of that. The other extreme is the CNC machine, where the tooling is elaborate and the majority of the "work" (programming) is done before the milling starts. Nothing wrong with that if it gets you what you want.

I do understand and enjoy the quiet of hand tools. But, I am with Clay; if I can have a fast way to rough out any component I will take it, if safe and reliable. I also use planes, knives and chisels and a lot of handwork finishing the component. I may be more like Don in that I do not like making jigs, especially when making the jig will take more time than the component I need right now. It is just a matter of where I want to put my time. Hogging off a bunch of hardwood is not one of them.

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http://www.Harvestmoonguitars.com

I’m no Luddite; I use plenty of power tools and jigs, for all the same reasons. Maybe more than the average hand builder, to be honest. I’m simply saying that this particular task (arching a fingerboard to a compound radius, ready for fret installation) is one where I don’t experience any overall increase in efficiency by mechanizing any part of the arching process. And I’ve tried, because, again, I can legitimately be accused of loving me some jigs. Part of this is my conversion here lately to the idea of fretting as the last thing I do. Once the fingerboard is glued to the neck and the neck is attached to the body, hand methods are the way to get the fingerboard flat and straight, and then perfectly arched. Arching before the fingerboard is attached to anything just feels premature.

I use my CNC router and a 3/4" d round nose bit. The job takes about 30 minutes but I'm off doing other things while it's running. There is some fine sanding left to do before fretting but it's a minor amount. Anybody else use this method?

I do... followed by fret slots, inlay motif, and outside profile. I then mount the FB on edge and cut the sidemarker pockets. The FB ends up requiring very light sanding and is very flat.

M

Here is a picture of the fretboard after the frets are cut and the edges are tapered. I cut the slots before the board was tapered and I found I could "rock" the board as I ran it over the blade to cut slots of fairly uniform depth. They may need a little touch up with a hand saw, but probably not much. I marked the taper on the board and cut close to the line with a bandsaw, and then cleaned it up with the jointer.
I could see myself milling and radiusing several blanks and having them on hand in an unslotted state. I use several different scale lengths depending on the instrument so that is as far as I would take it.
One thing to note when using that router bit - If you don't pretaper the blank in thickness, when you taper the sides the nut end will be slightly thicker on the edges than the soundhole end (1/32 -1/16th). In some ways it is an advantage - When it comes time to refret and remove divots the top end will have a little more "meat" on it to be sanded off. Likewise a neck reset possibly may be avoided by planing and sanding the upper end of the board as is sometimes done for classicals. The non uniform edge thickness might bug some people and possibly require a change in the way you dial in the neck angle when building, but tapering the board thickness either before (easier?) or after radiusing would bring it back to typical.

I use a 1" core box bit, and then the frets with a .020" bit (I use Jescar wire with a .020" tang). 1/4" down cut for the profile cut. Very little post processing.

Never used the CNC to do the side dots. How do you accurately set up and fixture the board on edge for that?

Never used the CNC to do the side dots. How do you accurately set up and fixture the board on edge for that?[/quote]

I took 2 pieces of europly about 3”x18” and glued and screwed them at 90°To each other. I clamp this down to my 8020 deck and clamp the FB to the vertical side of the fixture. Then it’s just a matter of having an accurate drawing to create the vectors. I tried to find an image of the fixture with no luck. Hopefully my explanation isn’t too criptic.

Here is a pic of what I usually do for side markers.

M

Here is my program for a 12" radius. I have not had any luck using bits for fret slots. They break so easy. Maybe you can convince me to try again.

G90
G1F100
G59
G61
Z.5
X.2562Y.325
Z0
o100repeat [624]
G90
G19
G2Y3.075R12.3862
G91
G1X.015625
G90
G19
G3Y.325R12.3862
G91
G1X.015625
o100endrepeat
G90
G1F100
Z.5
X0Y0
M2
%
(Z0=part surface -.085)