Fingerboard Radius Jig for Router

[LedBelli Bass]

I have gone back to my original jig. I've had some recent requests for info, so this post is to address that.

 

[LedBelli Bass]

I have gone back to my original jig, but it has been modified from the earlier verson. I've had some recent requests for info, so this post is to address that.

The Jig:

Close-up of the fingerboard bed:

The router carriage. The router sets inside the sled . . .

The endpieces in their respective radii:

The length of the fingerboard bed is 38 1/4"

The pipes are 41" long.

Note the shims on the 12" radius. The make up for unwanted taper to the fingerboard.

To use: just tape your fingerboard to the bed. Set the pipe carriage on, put your router in the sled, set the proper heights, and go . . .

 

[funkomatic]

That is absolutely brilliant.

You could make that into a wood thicknessing jig, too.

 

[LedBelli Bass]

Don't ask me . . . .

 

[Beej]

Oh, wow. Cleve, I am once again in your debt.

This thread is a perfect example of why this forum is so incredibly valuable. Hopefully the fact that we have this amazing community here doesn't go unrecognized by anyone. To think that only 15 years ago, all of these resources cobbled together in one place was impossible for me to imagine...

 

[stevetx19]

this is phenomenal...

i'm sorry, i don't understand what you mean regarding the shims on the 12" radius and the unwanted taper; could you elaborate?

thanks!

 

[tjclem]

 

[tjclem]

Oh, wow. Cleve, I am once again in your debt.

This thread is a perfect example of why this forum is so incredibly valuable. Hopefully the fact that we have this amazing community here doesn't go unrecognized by anyone. To think that only 15 years ago, all of these resources cobbled together in one place was impossible for me to imagine...

Very well stated!! Nice jig. Thanks....t

 

[LedBelli Bass]

this is phenomenal...

i'm sorry, i don't understand what you mean regarding the shims on the 12" radius and the unwanted taper; could you elaborate?

thanks!

Sure. Because the pipes are 5" apart, and because a 12" radius is a smaller circle than a 20" radius, the pipe would actually run slightly "downhill" from the 20" to the 12".

This downhill runout is actually pretty significant. The more the difference in radius between the two endpieces, the more pronounced this runout is. On a 12/20 it's about 1/16" over 3 feet.

Therefore, I put shims under the 12" circle to correct this runout and keep the sled running level.

Of course, this is a non-issue on a device with a constant radius, say a 12/12 or 16/16. Both ends would be even.

All that being said, there are times when one might want to exploit the runout. On my first bass I actually tapered the fingerboard with the equivilant of about 1/2 - 1 degree of runout (thinner at the nut) so that I had simulated a neck that was laid back. I intend to do the same on my next bass.

Clear as mud?~!

 

[LedBelli Bass]

That is absolutely brilliant.

You could make that into a wood thicknessing jig, too.

You could, particularly for smaller pieces of wood that would not be planer-friendly . . . bridges, faceplates, etc.

Of course, you would need to make jig end-templates that were straight/flat.

 

[pilotjones]

Like LB said, the shims are there because the pipe spacing produces a different "between the pipes drop" at each end.

When the shims and the cutting depth of the router bit are adjusted so that the bit would just recut the curve of the end panels (if it could be brought down that far), then the radii that are specified by the end panels are produced. If the bit were high or low of the virtual cone surface formed by the two end panels, a correspondingly larger or smaller radius would be produced. (Example: if you adjusted it so that the router would just skim the end panels, then you dropped the bit by 1 inch, you would get a cut from 11 inch radius to 19 inch radius.)

The radii of the fretboard are further determined by where the blank is placed between the ends. A blank that ran clear from one end board to the other would receive the same radii as the end panels; a smaller board placed in the middle gets radii from somewhat larger than the small end, to somewhat smaller than the large end.

LB, I don't see the shims in the picture. Are you putting collars on the pipes, or a strip on the riding surface of the small end panel?

 

[LedBelli Bass]

LB, I don't see the shims in the picture. Are you putting collars on the pipes, or a strip on the riding surface of the small end panel?

Look at the bottom of the 12" endpiece; there are two 3/4" aluminum channel pieces between the endpiece and the base.

 

[Stone Age]

That is pretty slick. Looks very manageable to build and use.

 

[funkomatic]

How high is your fretboard bed? It looks like it is ~6".

It also looks like the top of the endboards clears the bed by about 1/2" is that about right?

Thanks

 

[LedBelli Bass]

How high is your fretboard bed? It looks like it is ~6".

It also looks like the top of the endboards clears the bed by about 1/2" is that about right?

Thanks

Pretty close. The endboards are 3/8" clearance at the crown. 6" is the about right for the fingerboard bed.

 

[RDW]

Brilliant! Best DIY radius jig I've seen. Thanks for sharing.

 

[DerHoggz]

How do you secure the fretboard?

 

[LedBelli Bass]

How do you secure the fretboard?

With double-sided carpet layers tape. I only use about 4 tabs (2"x2") over the length of the fingerboard and that secures it very well. Too much tape makes it difficult to remove and you risk damaging the board.

You just want to be sure that the fingerboard is secured FLAT, with no raised areas. Use as little tape as needed to accomplish this.

 

[DerHoggz]

Goodness you guys love double-sided tape.

Great jig, simple, yet effective.

 

[mikeyswood]

I'm going to bump this back to the top just because of the brilliant simplicity. Great job Cleve!