Official Luthiers Forum!

So, addmittedly my math sucks.
There for, I am looking to you folks for some help

I would like to make a few of Sylvans taper jigs. He gives an explanation of how to calculate the
size below...

"The jig itself is just a piece of wood about 5” long (not critical) with two notches cut into it; one end has a 9/16” notch (the taper) and the other has a 9/32” notch. Notice the second notch is exactly half of the taper. You can just simply just notch a piece of plywood with the two notches or, to be really accurate you can cut 3 pieces and glue them together to make the jig. The three pieces I used were 9’16” x 5 1/4”, 9/32” x 5 1/4”, and the center piece was 1 1/8” x 4 3/4”. Just glue them together as in the photos. The total width of the jig must be less than the total width of the fingerboard (in our case 2 1/4”). The finished jig has notches in opposite ends that are 1/2” deep although, as you will see in a minute, that too, is not critical."



OK, armed with that info, what size would I need for
A. 1 11/16 nut and 2 1/8th at the 12th (Not the 14th) fret?
B. 1 3/4 nut and 2 1/4 at the 12th (Not the 14th) fret?
C. 1 7/8 nut and 2 3/8 at the 12th (Not the 14th) fret?

For some of you math/excel wiz's' maybe a formula could be made up where you
enter the two measurements and it tells you the size? THEN what would be really cool is if
we could also add in the total thickness of the fretboard binding, and the formula subtracts it..

Thanks in advance for any help

FYI< here is Sylvans article in the Tools and Techs section
http://luthiersforum.3element.com/pages/jig_tools_tech/sylvan_wells_fb_taper.htm

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Lance@LuthiersForum.com

Todd,

That looks about right. Since I didnt have an overall fretboard length, I did my spreadsheet to calculate the fingerboard width at each fret. (Taper left as a exercise for the reader).

d = s – (s / (2 ^ (n / 12)))

where:
d = distance from nut
s = scale length
n = fret number

tangent of fingerboard slope = (width at 12th - width at nut)/scale length
width at end of blank = width at nut + 2 * tan * length of fretboard
width at any fret = width at nut + 2 * tan * distance from nut

scale length 24.9
width at nut 1.75
width at 12 fret 2.25

tan 0.020080321
distamce to fret width of fretboard
0 0 1.75
1 1.397529614 1.806125687
2 2.716621918 1.859101282
3 3.96167926 1.909103585
4 5.136856903 1.956299474
5 6.246076893 2.000846462
6 7.293041148 2.042893219
7 8.281243816 2.082580073
8 9.213982929 2.120039475
9 10.09437142 2.155396442
10 10.9253475 2.188768976
11 11.70968448 2.220268453
12 12.45 2.25
13 13.14876481 2.278062844
14 13.80831096 2.304550641
15 14.43083963 2.329551792
16 15.01842845 2.353149737
17 15.57303845 2.375423231
18 16.09652057 2.396446609
19 16.59062191 2.416290036
20 17.05699146 2.435019738
21 17.49718571 2.452698221
22 17.91267375 2.469384488
23 18.30484224 2.485134226
24 18.675 2.5

length of fretboard 19 2.513052209

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GregH
Fot Wuth

I think that type of setup will work fine, but nowhere near as consistant as this style. Plus, you dont need a new set every time someone wants a different nut or saddle spacing. As well, you have a ful length support for the FB, and a toggle clamp holding the FB in place so it cant move or bind.

easy to make, easy to use ....

Step one - set table saw fence, to jig amin fence distance as required, making sure to subtract binding/purfling form final dimension.

Step two - set stop two at nut end, to final nut width, again, taking into acct binding purfling.

Step three - set stop one, to half difference between first two settings, this gives even taper on each side of the fretboard. There is no need to ahve the fretboard at any given width, this will auto trim to its final size.

Here are some shots of the jig ... I have two, one set up for my std fretboard size, accounting for 80 thou binding and 20 thou purfling each side, 1.75 nut width, 2.350 end of FB width. the other is for whatever else I need to make, and gets adjusted with a micrometer - the cuts come out within 3-5 thou every time.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Uhhhhhhhhhh.........

Okay Tony....I can make some guesses here...but they are just that. Could you answer a few questions about your jig?

"set table saw fence, to jig amin fence distance as required,..."

Set the table saw fence in reference to what?...what's an amin?
Which stop is stop 1 and stop 2?
When you subtract binding thickness, is it the total thickness of both bindings on each side of the fretboard?

I actually have more questions but will stop there...so that my own level of incredible incomprehension isn't so apparent!!! I know you probably did this on the fly so if you could slow down a little for me that would be fantastic! Your help is most appreciated...believe me.

Chris

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There is no difference between the man that thinks he can....and the man that thinks he cannot.

I had to reply. It takes less than 10 minutes to make a jig for any particular size of taper. You just need to know two things: nut width and total width of fretboard, in order to make the jig. Taper is defined as the difference between the total width of fretboard and the width of nut. Whatever that number is, is what the taper is (i.e., 5/16", 9/16", 3/4" etc.). Once you know that number that defines one side of the jig as described above in Lance's post. 1/2 of that number defines the other side. I always make these jigs with three pieces cut on the table saw and glued together. Then I know both of the size of the "fingers" are absolutely correct. The only other variable in cutting the fretboard taper is you must have cut the fretboard to its' correct length before doing the actual tapering (longer or shorter fretboard does not change the numerical number taper but it does change the shape).
Additionally, if you want binding for the fretboard, just measure it (total binding width) and subtract it from the total width of the fretboard. The taper remains the same but the total width is the total binding width LESS the thickness of the binding you will glue on later. Very quick and very precise!
Additionally, if you need to replicate another fretboard this jigging makes it ultra simple. Two measurements and you are good to go!

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Sylvan
http://www.wellsguitars.com

Todd -
I absolutely agree with you. That is a function of the total length of the fretboard.

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Sylvan
http://www.wellsguitars.com

This actually does nothing to answer Lance's question, but I had to go another route because the outfeed length on my TS fence wouldn't work with Sylvan's jig. So I built a full sled. A little more work and only one fixed taper (but how many variations would one need? 2? 3? 4?) but it's another alternative for those with a smaller saw.

First pass, fret side up, nut forward:



Secomd pass on the other side, fret side down, nut forward:



Finished product:



Like Sylvan said, I just vary the width for the second cut based on binding width.

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Wes McMillian
Santo, TX
http://www.wesmcmillian.com

Also note that board length wouldn't matter with a full taper sled. You could leave it long for, say, custom shaped fingerboard ends at the soundhole and such.

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Wes McMillian
Santo, TX
http://www.wesmcmillian.com

I've used Sylvan's system ever since he wrote it up. I love it. I have a small table saw too and had to make carriers. Mine is a little narrower than the final width of the fretboard and I just use a featherboard to keep it tracking. I've used the same taper and length I set up for a 25.4 scale for a 24.9 and for a 20 and 18 fret board and the difference at the 12th fret is really negligible. For the 18 fret I just cut off what I don't need after the taper is cut.
I really like Tony's Karol's setup. Very slick.
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.

Ah ... good idea Sylvan making it a three piece glue up on your taper jig(s) .. otherwise its a bear to get the fingers the exact thickness as required.

Now back to the questions on mine ...

Setting the table saw fence - first, you need to know how wide the wider end of the FB is going to be, and take the binding (if adding binding) into acct - ie subtract it to get the CUT fingerboard width (then you will add on the binding to get your finished width, at each end. So lets say the fingerboard is going to be 2.250, and we are going to have .100 of binding - thus the CUT fingerboard width becomes 2.050. You need to set the table saw fence, such that witht he jig on the table saw, the main fence of the jig is 2.050 away from the blade. Now lets set the stops, 1 and 2 (2 being the one at the end of the jig, that gives the final width of the CUT fingerboard at the nut end, taking into acct binding) So we start with setting stop 2, and lets assume the nuut is going to be 1.75 - thus the CUT fb width is 1 .55 inches. Set stop 2 to this, measuring from the blade to the stop. Stop one needs to be set to the difference between the jig fence,and stop two - so add 1.55 to 2.05 = 3.6, and divide in half - set stop one to 1.80 inches.

Now lets cut the fb - step one ... with the nut end at the end of the jig with the stops, put the board with the nut end at stop one, lock in the toggle and cut.
Step two - flip the fb over (ie cut the taper on the opposite side ) and place the fb nut end at stop two, lock in and cut - its done.

Note that the FB does NOT need to be cut at any given width, it only needs to be square at the nut end to one straight side edge (and make sure that side is in towards the fence on the jig for cut one, and then the other side will get cut straight anyway)

Ok, so maybe its not as simple as having a whole bunch of Sylvans jigs kicking around, but with one jig I can cut any taper, and it takes into acct any binding/purfling scheme as I set it.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Wow, thats a lot of math. I use Sylvian jig with almost no math...LOL!

I simply cut my fingerboard to final length ( aprox 18.25" for a 22 fret 24.75 scale).

Simple math: The nut is 1 3/4 wide. The end is 2.25" wide. The difference between the two is 1/2". Simply make one notch on the jig 1/2" wide the other notch will be half that or 1/4" wide. (whatever the difference is between the nut width and the final width is, that is your jigs widest notch. The smaller notch is always half of that).

The cut: Set the blade to 2.25" wide (final width of f-board). Cut the first notch with fret slots pointing up with the 1/4" jig. Than flip the board over slots down and cut the same direction with the 1/2" jig. Done. Your cutting from the 1st fret toward the 22nd in a both cuts.

For bound fingerboards, just subract the total width of both sides of the binding from the last cut. If you use .060" binding, subtract .120 from the final cut. So in my case the width is 2.250" minus the .120 binding. I set my saw to cut the final width to 2.130".

Thanks to Sylvian for a great little jig. I have cut quite a few fingerboards now using this method and it always works....AND the gig is small and easy to store.

I did have to make a table saw fence extension, but it can be used for lots of things not just f-boards.

J

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Joe

hey J, its whatever works best for YOU that counts .... I have always done mine like this, so for me its pretty simple to use.

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Tony Karol
www.karol-guitars.com
"let my passion .. fulfill yours"

Hey Tony. For sure! What ever works...that is the bottom line. I love your jig set up. Very flexiable. For me, I am just doing one size fingerboard/neck. So for right now, flexibility is not that important. Repeatability is important for me.

BTW Tony, I guess it wasn't clear. I was saying "WOW that is a lot of math" to Todds spreadsheet and the long list of numbers that he posted after that.


Joe

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Joe