Simple Fretboard radius jig

guitarbuilder

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I have referenced this design a lot in this forum but the concept really goes back before the internet.

In the early 1980's when I first started out building instruments, I wanted a way to put a radius on a fretboard. On my first couple guitars, I had used some pre- radiused ones that Gibson sold as seconds that I bought through a couple repair shops in Buffalo.

At the Fox school where I built my first guitar, we radiused the fretboards with a scraper followed by a sanding block. I never really felt that that was the best way for me to make them.

Having purchased and read in the Siminoff book that he radiused his fretboards by rotating the neck by hand on a belt sander, I figured that would be a good way for me to ruin good wood.

Now in the beginning, I did most of my building at work after hours. One day after changing a bandsaw blade, I got this idea that the bandsaw trunnion produced an arc and that I could adapt that idea to the router. Just like that.

So using some plywood, I cut out the parts and glued them together. It was for a full size router with a 6" base. It ran on about a 4' long track made from plywood. I wanted to be able to do bass fret boards too.

The base was just a plywood rectangle with two guide pieces of wood along the edges. The router produced nicely arched fretboards! It did leave some swirl marks and they needed to be sanded out.

How do you make the arcs? The arcs were made with a router mounted to a long piece of wood that rotated on a pivot. I had seen in a few different how to magazines in their " methods of work" columns on how to make round table tops using the router to cut it out. This led me to how to make consistent radius arcs.

I also realized the scrap when cut into shorter pieces and glued together could make a radius block for sanding. Funny how things work eh? Before that there were no wood radius blocks for sanding.

I started to make pretty decent necks. Then comes the internet.

MIMF starts one of the first forums. I post my radius jig idea there. It's in the MIMF archive. Other forums spring up including TDPRI. I join here. Then more forums start to spring up.

In the OLF, a guy named Todd takes the radius jig idea from Mimf and makes a tutorial. He modded it a bit. That was useful because he had a drawing of the parts. The jig was pretty well received from most of those who built it. For some reason, that has all disappeared.

I shared my idea here. The idea took off with a switch of pvc pipe for the wood rails.... the rest is history.

Anyway, I have recently started to make more necks again and I decided I wanted a smaller version of the jig for a trim router. So this is a scaled down version. I've been wanting to do this for a while, so here we go.
 
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guitarbuilder

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That sub assembly sits on the arcs. This still needs a few more pieces. To be continued. Oh, if you make the arcs in reverse you can make radius sanding blocks too.
 

guitarbuilder

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Old version base part upside down. I only did fretboards back then.






The top part that holds the router. The opening were for the handles of the Craftsman router. The things on the side keep it on the rails...otherwise it would fall off. The versions you see with pipe don't have this feature and you can't control it as well. This is the original one. I never had a need to make a 2nd, it worked so well.
 

RogerC

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I knew this was your version, Marty, but I didn't know how far back it went. Thanks for filling in the back story, and thank you for being kind enough to share it with everyone. This was the very first jig (of any type) I'd ever built. It has the 2 most important hallmarks of a great design: Simplicity and effectiveness
 

guitarbuilder

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Cool. I've seen this jig here before. I'll build one one day.
Thanks for sharing Marty!

I knew this was your version, Marty, but I didn't know how far back it went. Thanks for filling in the back story, and thank you for being kind enough to share it with everyone. This was the very first jig (of any type) I'd ever built. It has the 2 most important hallmarks of a great design: Simplicity and effectiveness

Thanks. I believe that this is one of the best things I ever came up with on my own and it's weird to see all the various iterations of it all over the place...
 

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I unscrewed the bottom of the clear plastic base, drilled the screw holes out with a 1/8" bit and attached it to the wood with #6 x 3/4" sheet metal screws. The base is offset from the center of the router. This will be a dedicated trimmer if it works well. I'll just leave it on there.

 

Mat UK

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It's great thinking and design like this that makes guitar building so accessible - another fantastic jig that is within most people's ability to produce without breaking the bank.

It would be brilliant if there was a sub forum that just contained verified jig plans just like this... It would also give the creator the opportunity to gain well earned credit!
 

guitarbuilder

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Thanks for sharing this Marty and the story, too! The best ideas really are the most simple!

Cheers,
Joe

It's great thinking and design like this that makes guitar building so accessible - another fantastic jig that is within most people's ability to produce without breaking the bank.

It would be brilliant if there was a sub forum that just contained verified jig plans just like this... It would also give the creator the opportunity to gain well earned credit!

Thanks guys! Most of this can be made from shorts or scraps.
 

guitarbuilder

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Gluing together the bottom on the fly. I stuck some glue and corner blocks in there to help hold things together before I add some dowel or screws. Two new parts are the rectangular cross pieces that are about 1" x 5" long each being glued with the HF bar clamps.

 

guitarbuilder

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I added 4 sheet metal screws to the corner joints and glued on 4 blocks ( 2 on each side) to hold the top in place onto the bottom. All that's left is the track.

 

guitarbuilder

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I took a piece of melamine shelving and put a couple pine guides along the sides with double sided duct tape. Now I need to find a straight bit.

 

guitarbuilder

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Great Jig. Wish I had you as a shop teacher when I was young, I would've started into the fantastic world of woodworking and guitar building a lot younger.

Thanks.... we did do some cool stuff over the years including a few guitars here and there.

I had to order a longer bit than I had here. I'll probably will see it in 1-2 weeks.
 




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