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View Full Version : Router Jig for Radiused Fretboards



saltytri
07-26-2017, 11:36 AM
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!"

https://farm5.staticflickr.com/4327/35381733853_8c9998b6b3_z.jpg

https://farm5.staticflickr.com/4322/35349702854_53265f3de5_z.jpg

https://farm5.staticflickr.com/4298/35381733433_f0afa0821e_z.jpg

sequoia
07-26-2017, 06:08 PM
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?

saltytri
07-26-2017, 07:12 PM
https://farm5.staticflickr.com/4322/35388034343_c8c3658c41_z.jpg

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

jcalkin
07-27-2017, 02:22 AM
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?

Michael N.
07-27-2017, 02:53 AM
Sanding that amount is probably strenuous. Planing with a block plane isn't, in fact it's easy and a lot less dusty.

saltytri
07-27-2017, 03:07 AM
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.

https://farm5.staticflickr.com/4309/35363124074_dc14dcce5e_z.jpg

https://farm5.staticflickr.com/4327/36031856312_b41dc6c16b_z.jpg

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."

https://farm5.staticflickr.com/4327/35363129614_f6d00672e8_z.jpg

jcalkin
07-28-2017, 04:05 AM
Sanding that amount is probably strenuous. Planing with a block plane isn't, in fact it's easy and a lot less dusty.

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.

Beau Hannam Ukuleles
07-28-2017, 09:20 AM
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!


https://www.youtube.com/watch?v=VzWoUrBE_J0

saltytri
07-28-2017, 04:07 PM
That take the prize for cool! I'll be happy coming in second to John Greven any day.

Michael N.
07-29-2017, 02:34 AM
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.

resoman
07-29-2017, 04:54 AM
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

sequoia
07-29-2017, 05:56 PM
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.

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.

saltytri
07-30-2017, 05:02 AM
Of course, he's built over 2000 guitars so he seems to have it under control. ;)

Beau Hannam Ukuleles
07-30-2017, 11:18 AM
Of course, he's built over 2000 guitars so he seems to have it under control. ;)

I agree- if John Greven does it, it works.

Michael N.
07-30-2017, 11:07 PM
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.

Timbuck
07-30-2017, 11:38 PM
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.

saltytri
08-05-2017, 01:19 AM
Maybe he uses shims underneath to compensate for different thicknesses.

mountain goat
08-05-2017, 01:57 AM
Of course, he's built over 2000 guitars so he seems to have it under control. ;)

+ 2

.....

finkdaddy
08-19-2017, 12:05 PM
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!

finkdaddy
08-21-2017, 06:44 AM
Anyone want to buy some slightly used StewMac radius sanding blocks?

Any chance that you still have your old block? I'm going to be buying one, and if I don't have to pay StewMac, all the better.

saltytri
08-21-2017, 10:07 AM
PM sent....

jupiteruke
10-19-2017, 09:41 AM
The original jig is very elegant. When I thought about it, I realized that one does not need to make full convex sides for the jig to slide upon. Two points are sufficient to make the top concave arc slide in a circle. With this in mind I made a modified jig out of 3/4" PVC pipe for 'rails' (very uniform, and slippery), and the arc plates I cut out of acrylic on a laser cutter. I put a threaded insert in the top and drilled a hole in the acrylic baseplate I use with my trim router so that I can simply attach the trim router with no need to change baseplates or anything. Works great. Here are some pictures, and a measured drawing I did first to get the dimensions reasonable.

saltytri
10-19-2017, 11:07 AM
That'll work! I've seen other versions of this jig that use pipe in the same way, so presumably, others are getting along just fine with your approach.

Bob Orr
10-29-2017, 06:59 AM
I use a very similar set up using pvc pipe and it works great. Bob

mikeyb2
10-29-2017, 11:10 AM
Firstly, with this type of jig I've read that routing across the grain can be problematic with tear out, so do you rout lengthwise up and down the board, turning the radius a touch each sweep?
And what size and type of router bit is used for the best results? Thanks Mike

saltytri
10-29-2017, 11:45 AM
I've never seen any tear out using a Freund 1/2" diameter straight bit with two carbide flutes. Some woods may be more prone to this but it hasn't happened with West African ebony, Macassar ebony, EIR, maple or the junk fir that I used to test the unit when it was first completed. I move up and down the board lengthwise using quite a few passes, probably a dozen or more, and always radius before cutting the fret slots to avoid the possibility of chipping the slot edges. I don't know how much of a risk this is but my process of cutting the slots doesn't care if the board is flat or radiused so I do the slots last so there's no risk at all.

Bob Orr
10-30-2017, 06:20 AM
I use a large 1/2 inch Triton Router and this bit from Wealdon, a surface trim bit and I use the 50mm one.

https://www.wealdentool.com/cgi-bin/sh000001.pl?WD=surface%20trim%20bit&PN=Online_Catalogue_Surface_Trim__3_Wing_250%2ehtm l#aT2410

I take a run lengthwise up the middle of the board then take alternate runs up and down either side. I never rout across the grain. The bit I use is good because the curved outer edge doe not dig in so you don't get tram lines like you can sometimes with a straight cutter. I also radius before cutting fret slots or tapering the board blank. Bob

mzuch
10-30-2017, 07:11 AM
Or, you can just use one of these router bits (https://www.ebay.com/itm/Fretboard-Router-Radiusing-Bit-16/112454716172?hash=item1a2ed2cb0c:g:9IAAAOSwvflZTiV C)and throw away the complicated jigs.

sequoia
10-30-2017, 04:38 PM
Or, you can just use one of these router bits (https://www.ebay.com/itm/Fretboard-Router-Radiusing-Bit-16/112454716172?hash=item1a2ed2cb0c:g:9IAAAOSwvflZTiV C)and throw away the complicated jigs.

These bits are made by SJE tools out of Australia(?) I believe. He posted on here a couple years back and offers many different radius sizes. He also posted a demo video. I have never used one so can't vouch for them.

https://sje-tools.com/

saltytri
10-30-2017, 05:53 PM
Those router bits have been discussed here before. Call me a weenie but they sure make me nervous!

http://forum.ukuleleunderground.com/showthread.php?104866-Fretboard-radius-cutter