lacking radius block, what would you use?

[fretless19]

Title says it all really. In lieu of the proper tool for the job, what other ways of radiusing would you / have you used; to what effect?

Example Steve Wyn (I think?) uses a beltsander and hangs a neck over it in a sort of swing, with one end of the neck rotating at 15" and the other at say 9". He produces a perfect conical radius in this way.

 

[bholder]

Wow. Radius blocks aren't that expensive, but yeah, they can't do accurate conical shapes so well without a lot of painstaking work.

 

[fretless19]

Wow. Radius blocks aren't that expensive...

I agree they are the go to tool for the job, I am just interested in what other approaches people have used.

 

[fretless19]

Also, nice discipline avatar .

 

[FBB Custom]

Radius block is definitely the cheapest.
I think Carvin does CNC.
Others use the radiusing jig and an edge sander as Wyn does. Grizzly even sells the jig.
Some people freehand on the edge sander. This takes a lot of practice and you will need radius gauges to check your work.
I have seen someone do it on a pin router.
LMII uses a shaper to do it.
I used to have a router fixture to do it.

 

[HaMMerHeD]

A lot of people do it with handplanes.

Router jigs seem like the quickest and most reliable method.

 

[fretless19]

A lot of people do it with handplanes.

Router jigs seem like the quickest and most reliable method.

Do you mean to stair step with the router, or an actually radiused jig?

 

[Scoops]

Do you mean to stair step with the router, or an actually radiused jig?

I'm assuming an actual radius jig. I built one similar to this. You still have to go back and fine tune it once you've used the jig, but it works.

Fingerboard Radius Jig for Router

 

[fretless19]

Fingerboard Radius Jig for Router

That is a pretty brilliant setup.

 

[yoshi]

...so happy my preference is a completely flat fingerboard

 

[fretless19]

...so happy my preference is a completely flat fingerboard

I find flat boards to feel almost concave.

 

[Bruce Johnson]

You don't need a radius block to shape a fingerboard surface to a radius. A good stiff flat block will work just fine. In fact, a flat block is usually faster, because a smaller strip of abrasive is cutting at a time, so it doesn't tend to clog and skid. You work it in long straight strokes, rocking it to form the radius, checking it regularly with a radius gauge. To make it easier, start by sanding shallow bevels of equal size along either edge to use as guidelines. It really isn't very hard to work it to the radius that you want.

I have a set of the Stew-Mac radius blocks that I bought back in the early 1990's. I hardly ever use them. I find them to be so slow and clumsy to use.

I'm a pro Luthier, and I radius 2-8 fingerboards a week. I do most of them with a specialized router radiusing fixture, which I can dial in and adjust very accurately. It's fast. But occasionally I'll need to radius one by hand sanding with a flat block.

 

[/\/\3phist0]

G&L uses the swing belt sander method, works great, quick accurate easy to do many repeatedly.
Incidentally they use the same jig for cutting the slots for the frets once the board is radiused.

 

[HaMMerHeD]

Works great....if you happen to have a giant belt sander.

 

[Bruce Johnson]

I'm surprised that G & L and many other shops use those belt sander type radiusing rigs. I built a rig like that back around 1993, and messed around with it for a while. I never got satisfactory results with it. It roughed out the radius okay, but I couldn't get consistent straight surfaces. Too much heat buildup and deflection of the sanding belt. Every fingerboard needed hand block work to level it out. I finally abandoned that whole approach and went with the routing rig, which has been working great since then.

 

[FBB Custom]

One thing to watch out for with the router jig is splintering at the edges. I had a little bit of trouble with that when I was using a jig. Plan out your cut carefully.

For what it's worth, Bruce has a way to do almost every step of building a bass that would be harder for me to do but is somehow easier for him. I can't imagine using a flat sanding stick to radius a fingerboard but I don't doubt that Bruce does it in his sleep.

 

[fretless19]

Great information guys, thanks!