Router Sled - Fretboard Radius Jig

[grimjim]

OP if you're going to stay with your original design, I would suggest putting horizontal blocking in your radius box to keep it square and stabilize it better.

I like seeing all the different ideas for this. I'm a cabinetmaker and geek out over stuff like this.

 

[TerribleTim68]

Okay, Final Changes -
So I needed to widen out the radius guide to fit the new width of the router base. Taking some suggestions here, I added the supports "inside" and up against the sled bed, this makes the guide a lot more stable and keeps it aligned better -

I also added some screws to everything so we're not replying just on CA glue here. Then every sliding surface got a coating of Johnson's Paste Wax so it all slides better. Everything seems to be moving easily. The new position of the supports also gives me a little extra distance the radius guide can slide past the sled bed too, just in case -

I guess the next step is to see if I can do something with it.

 

[RichterScale]

I added the supports "inside" and up against the sled bed, this makes the guide a lot more stable and keeps it aligned better

I completely forgot to mention this little detail that I also did on mine. It helped reduce binding and chattering as it moves side to side. But you got it .
I didn't have paste wax at the time, so I used dry graphite spray. It works, but wears off quickly and is messy. I don't recommend it and will be using the wax on the jigs, now that I have some.

 

[Jaygetsreal]

Love the way you have approached this challenge and the way you have fine tuned the design to perfection! Bravo!

I tackled this back in 2017 but with a compound curvature for DB fingerboard. I used alloy rails and a wooden hinged swing arm to hold the blank underneath. If you're curious it's here EUB design and build and some lessons learned Have used this EUB for a few years now and love it. I also did a short video on request for another TBer who was doing a similar project.

Will follow your progress with great interest.

 

[tr4252]

I enjoy threads like this a lot. It will probably be remembered by many and inspire a few people in their future work.

It's amazing what you can do with wood on a project like this. I do similar work; never radiused a fingerboard, though. Birch and maple ply are handy, where I think I can get away with it in a jig, fixture, etc. A jigsaw and a belt sander are tools I use a lot. As a long time metalworker, I'm inclined to think in terms of linear bearings, milling parts, and so on, but working with stable wood is so much easier and quicker, depending on the desired end result. One quality I like is that an untried sub assambly like a traveler can be tacked together with a few spots of white glue, tested, then knocked apart and revised without starting from scratch (a lot of my creations have to be modified a few times before they do what I wanted them to).

Thanks for starting this thread Terrible Tim68, and to all the other how-to threads we get here from various members. You mentioned earlier that you were concerned about the glue being enough to hold your device together. Jobs like this, I like to screw the parts together, don't trust glue much, especially cyanoacrylate, but it's handy for jigging up assemblies quick and dirty. I remember how I used to have to come up with elaborate clamping methods to hold odd pieces together while I drilled them, then one day realized the parts are already "clamped" if they're glued. I just drill into them as if they were one piece. Pilot holes and countersinking are required; no big deal.

Tom

 

[Plain Old Barry]

I didn't have paste wax at the time, so I used dry graphite spray. It works, but wears off quickly and is messy. I don't recommend it and will be using the wax on the jigs, now that I have some.

If paste wax isn't handy, another great way to "lube" sliding MDF edges on jigs is a layer of clear packing tape.

Clear tape is also a great glue resist for pressing blocks or clamping cauls. When I'm vacuum pressing veneer, I cover the faces of my MDF platens and they pop right off glue squeeze out.

 

[rudy4444]

Love the way you have approached this challenge and the way you have fine tuned the design to perfection! Bravo!

I tackled this back in 2017 but with a compound curvature for DB fingerboard. I used alloy rails and a wooden hinged swing arm to hold the blank underneath. If you're curious it's here EUB design and build and some lessons learned Have used this EUB for a few years now and love it. I also did a short video on request for another TBer who was doing a similar project.

Will follow your progress with great interest.

I'll check that out, as all the different creative ways that folks find to accomplish a task is of interest to me.

I documented my method for creating a compound radius board in my 30" semi-acoustic fretless bass topic (starting in post #27). My solution was to make a carrier to use with my router table that presented the board surface to a router bit.

 

[byacey]

I went in the opposite direction. I made a router jig, but would end up with random low spots. And when you have a low spot, you have to lower everything else to match. I switched over to hand planing followed by the sanding block.

My thought is to rough it out with the router, establish the radius, and then finish of with a handplane and a radius sanding block.

 

[byacey]

If I want to put some vertical taper into the fingerboard, I can by raising the nut end a little bit more. If I raise the nut end to 0.080" above "0", then the fingerboard will end up tapering from 0.250" thick at the heel to 0.220" at the nut. That's a common thing to do to make the side edges of the fingerboard look more even in height.

I wound up making a shim to put under the headstock end to make the margins on the sides more or less equal along the entire length. My first test run with the jig was on a pine blank, and I found the margin went to about half the thickness at the wide end of the fretboard. I made the shim half the difference between one end and the other.