Official Luthiers Forum!
https://www.luthiersforum.com/forum/

Fingerboard Radius Jig Question
https://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=31406		 Page 1 of 1
Author:  sdsollod [ Mon Mar 07, 2011 2:56 pm ]
Post subject:  Fingerboard Radius Jig Question
For my previous 5 builds I have used pre-slotted and radiused fingerboards...

I am getting ready to make my 1st fingerboard from a blank for a Taylor style Grand Auditorium. I know there are jigs of various designs, some using a router, but I came up with this idea that should work...

I intend to use Stew-Mac's 16" aluminum radius sanding block (yes, I sprung for it...) and construct a jig with guides for the radius block, on each side of the stablized fingerboard blank, that will limit the ultimate thickness of the fingerboard. The sandpaper will only cover the inner portion (approx. 2 1/2") of the sanding block, leaving the edges of the radius block to glide over the guides (MDF), thus evenly creating the 16" radius in the fingerboard.

My question is this... To what thickness should I make the guides to ensure that I have the proper overall thickness of the finished, radiused, fingerboard? Or, in other words, how thick should the edges of the fingerboard be? ...1/4" ...3/8"?

I hope this makes sense...
Thanks,
Steve
Author:  Brian Forbes [ Mon Mar 07, 2011 4:16 pm ]
Post subject:  Re: Fingerboard Radius Jig Question
Lets see a pic of what you are looking at, its hard to put all that together in my head. It seems too like it would be a snap to cover that radius sanding block you have with 60g and go to town on the fretboard to make your own radius. I do it myself with a 8" wood radius sanding blocks, and it's like a 15 min process.
Author:  Alain Moisan [ Mon Mar 07, 2011 8:49 pm ]
Post subject:  Re: Fingerboard Radius Jig Question
sdsollod wrote:
Or, in other words, how thick should the edges of the fingerboard be? ...1/4" ...3/8"?


Your looking at it the wrong way. Because the fingerboard is tapered, the edges will be taller near the nut and shallower toward the end of the fretboard, although the middle of if will have constant thickness.
Author:  woodbutcher50 [ Mon Mar 07, 2011 9:30 pm ]
Post subject:  Re: Fingerboard Radius Jig Question
Steve,

I can not see why it wouldn't work. Like Alain said, figure out how to get your jig to stop at the proper depth for the centerline thickness of the finger board. I make mine 1/4" thick at the center line. If your board isn't wide enough to hold itself tight in your jig, you might plan on holding it in the center of your jig with double-sided tape.

Mark
Author:  Alain Moisan [ Tue Mar 08, 2011 8:42 am ]
Post subject:  Re: Fingerboard Radius Jig Question
Hi again Steve,

Mark is right. It can totally work. What I told you about the fretboard side thickness is correct, but it doesn't mean your jig idea is wrong.

Sorry for my mistake!

(I edited out the part where I'm wrong in my previous message...)
Author:  Dave Stewart [ Tue Mar 08, 2011 9:20 am ]
Post subject:  Re: Fingerboard Radius Jig Question
You may also want to check out Mauro Marchesini's clever jig at
http://mimf.com/cgi-bin/WebX?50@204.ebw ... 2cb6f60b/8
Author:  nickton [ Tue Mar 08, 2011 9:57 am ]
Post subject:  Re: Fingerboard Radius Jig Question
That jig looks cool but it looks like you don't have much room to move the sand paper.
Author:  Alain Moisan [ Tue Mar 08, 2011 12:15 pm ]
Post subject:  Re: Fingerboard Radius Jig Question
Todd Stock wrote:
Or just double stick the board to a flat surface, mark with chalk (centerline plus across the width every inch or so), and sand evenly until the centerline just disappears...

If you want to invest time in a jig, I'd go with a router jig...they make pretty quick work of the job.


I agree with you Todd that a routing jig is much better. But I disagree that just sanding until the centerline disappears is good enough. It can work, I've done it in the past, but you still can induce a twist in the fretboard surface using this method.
Author:  sdsollod [ Tue Mar 08, 2011 12:53 pm ]
Post subject:  Re: Fingerboard Radius Jig Question
Thanks for the comments...

If I were to taper the board before sanding, I would expect that the edge would be thinner at the wide end and wider at the nut end... but I could sand the blank after cutting it to a uniform width, of say 2 1/4", from end to end, and using the sanding block, with 80 grit paper, sand it to thickness of side guides (of a determined thickness [1/4"?]). About 1/4" of the sanding block edges would not have sandpaper on them so the sanding block could glide over the side edge guides. The side guides would keep the entire thickness of the board uniform and consistent from end to end. Double-sided tape, registering pins, or MDF stops would keep the board stable. After the board is radiused, I can then taper it to the dimension I want, like 2 1/8" at the 14th fret and 1 3/4" at the nut. (..or as needed for binding...)

I thought that this could be an easy, straight forward way to radius my fingerboard blanks... [:Y:] I haven't made the jig yet, so I don't have any pictures...

What do you think... 1/4" side guides? (...as long as the center of the fingerboard is radiused... An overall starting thickness will have to be determined [3/8?])

Am I making some wrong assumptions?

BTW, I could start the radiusing with a plane...
Author:  ChuckB [ Tue Mar 08, 2011 4:55 pm ]
Post subject:  Re: Fingerboard Radius Jig Question
Sounds like it would work as long as the aluminum sanding block is not eating away at the mdf guides. You could still also taper your board in advance (in case you bind the board), as long as the guides remain parallel. As far as thickness, I make my FB's 1/4" thick in the center.

Chuck
Author:  Terence Kennedy [ Tue Mar 08, 2011 6:14 pm ]
Post subject:  Re: Fingerboard Radius Jig Question
Sylvan Wells has a sanding jig that works well to keep the radius block aligned. I used his technique successfully on a number of fretboards before I built a router jig. It's in his free articles section. I didn't run it through the sander first, just did the whole radius on the tapered and slotted board with the sanding block.

http://wellsguitars.com/Articles/Fretbo ... g_Jigs.php


If you build a router jig a box core head router bit with a 1/2" shank works well to avoid tear out. I've been using the design Todd Stock posted on the MIMF a long time back. Works great for a straight radius. Still use that Todd??

Image
Author:  Alain Moisan [ Tue Mar 08, 2011 8:38 pm ]
Post subject:  Re: Fingerboard Radius Jig Question
sdsollod wrote:
I thought that this could be an easy, straight forward way to radius my fingerboard blanks... [:Y:]


Well, don't put your hopes up too high. Even with a jig like the one you intend to make, radiusing a fretboard using a sanding block is nothing easy and strateforward! If you start at 3/8'' to end up with 1/4'' in the middle, you will need a two weeks vacation just to rest your arm and shoulder!

To figure out the height of your side stoppers, you will need to do a little geometry. Depending on the radius of your sanding block and the width of your block, if you want 1/4'' in the middle, you will have to extend the curvature all the way to the side of the sanding block to figure out the height of the stoppers.

Here is a little drawing which hopefully will help illustrate what I'm trying to explain:

Attachment:
Sanding block.JPG


Hope this helps!
Author:  Ian Cunningham [ Tue Mar 08, 2011 10:30 pm ]
Post subject:  Re: Fingerboard Radius Jig Question
Hand Plane beehive
Author:  Haans [ Tue Mar 08, 2011 11:05 pm ]
Post subject:  Re: Fingerboard Radius Jig Question
6" X 89" belt after glueing to neck to get it close. Hand sanded with radius blocks after it's glued to the box...really fast!
Author:  ChuckG [ Wed Mar 09, 2011 11:06 am ]
Post subject:  Re: Fingerboard Radius Jig Question
Rick Micheletti has plans on his web site for a good router jig. It's not hard to build and you can do a compound radius if you want. I use it for a 12" to 16" compound radius (nut to 21st fret) and it works very well.

http://www.luthierscooltools.com/Dwgs.htm#FB%20Radius%20Jig

Chuck
Page 1 of 1 All times are UTC - 5 hours
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/