Official Luthiers Forum!

My first guitar had a high neck action. When fitting the neck(minus the fingerboard) for the first time I was shooting for 3/32" above the soundboard in the bridge area. Obviously too much. Plus my fingerboard was too thick,so now my fingerboard is thinner, 7/32". So now the math.
Do most of you use a 3/8" thick bridge? So,3/8" minus 7/32" plus 1/16"? Clinton

   Bridges are actuall different thicknesses. Most production guitar companies with range 1/4 to as much as 3/8 of an inch.
    I use a rule of thumb so to speak 1 1/2 degree for a 28 foot top and 2 for a 25 foot taop radius. This will keep you within the range of the average bridge tolerances.
    To me .400 is too think I like to keep mu bridges around .375 if I can. The bridge adds mass so you want this to be as efficient as you can get. Too thin ad you can have a saddle fold over , too thick and you can kill the potential tone
john halltippie5339030.2364583333

[QUOTE=tippie53]    
    To me 3/8 is too think I like to keep mu bridges around .400 if I can. [/QUOTE]

John, is it my age? I think .400 is thicker than 3/8".

Ron

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OLD MAN formerly (and formally) known as:

Ron Wisdom

Somewhere in the middle of Arkansas......

That's what I was wondering? 3/8"= .375 My tops are are 30' radius. So what do you usually want, your fingerboard to plane the top of your bridge? Clinton

Mine are between .300 to .350 depending on the mass of the bridge wood.

Check out the Woolson/Fox jig for nailing the neck angle to match the angle of the upper bout. This takes any guess work out of the procedure.

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JJ
Napa, CA
http://www.DonohueGuitars.com

A queston about the Woolson/Fox Jig
I realize it allows you to find the correct neck angle to get the correct height
at the bridge postion, but what if that correct height doesn't match the body
of the guitar. Won't it then create a 14th fret hump or dip? Isn't the key to
have a Body that has the correct angle.    If the body has the correct angle.
the neck will align perfectly with the body and there for give you the correct
bridge height. (And have no change at the body neck joint)

Am I missing something?

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Andy Z.
http://www.lazydogguitars.com

Andy...as I understand the theory, the beam indexes off of the upper bout angle. The first step in the process is to allow the beam to match the body angle and lock it in once the indicator is just touching the bridge. Then with neck clamped to the board(which is now positioned at the previously determined angle) it allows one to rout out the tenon such that the cheeks are at the proper angle and match with the sides, the fret board lies flat on the upper bout and the string line projects precisely to the correct position over the bridge. Supposedly, the cheeks then require very little chiseling or filing and just minor flossing to get a tight fit.

I'm just completing the construction of the jig...I'll let you know if the theory works within the next week or so when I try it for the first time. I'll take pics and try to do a tutorial (hopefully, Paul can jump in and provide further clarification)

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JJ
Napa, CA
http://www.DonohueGuitars.com

Hi guys,
I have the Holden jig based off the Fox design. All the jig does is give you
a matching angle for the upper bout. In other words, its design
eliminates the possibility of the 14th fret hump. However, you need to
establish the proper angle for your upper bout beforehand.

In my opinion, the easiest way to do this is to use a radiused top that will
get you close to your needed clearance at the bridge. This will vary
depending on your bridge thickness and etc...   For me, 28' works just
about perfectly. For my design, I need an upper bout ramp that will give
me a 1/16" clearance at the bridge and this is without the fretboard. To
make it dead perfect, I stick a 1/16" spacer at the bridge and use a
sanding board to true the fretboard area - this requires very little sanding
and has no structural impact on the upper bout. In this way, I am able to
achieve a flawless neck angle every time and with minimal effort.

--
Simon

SimonF39030.0917476852

Clinton,
See Here

The difference in height between a 28' and 30' dome is only about .01" at the bridge location. Getting the ramp right as Simon points out is critical.

   You guys are right . A long day and I was tired. The point was 3/8 is the target and the upper and lower spec 1/16 from that but I hate to go over the .400 mark.
    Sorry for the confusion. Long days and short attention span.
   Hope this clears that up.

Simon, so you use 1/16" clearance for your neck(no fingerboard). When I put a 1/16" shim at the bridge area the line almost matches perfectly to my upper bout. With a little sanding, it should work.
So, guys, my question still remains, what are you lining up? Is your fingerboard planing with the top of your bridge?,with or wihout frets? Clinton

Great thread, i was also wondering about a better way to do this too, thanks!

Suppose you get the ramp TOO sharp...like 3 degrees...what's the best way to re-establish the angle? (I know, toss the body on the scrap pile, and pay closer attention next time?)

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http://www.presnallguitars.com

[QUOTE=L. Presnall] Suppose you get the ramp TOO sharp...like 3 degrees...what's the best way to re-establish the angle? (I know, toss the body on the scrap pile, and pay closer attention next time?) [/QUOTE]
Larry, you don't need to scrap anything. Just adjust the heal to fit properly (you'll be removing material from the top of the heal) then when you get it all set and in the proper plane, you can make a shim for under the fingerboard (should you need it). If the board is ebony, it's an invisible fix.

Clinton,
For good action that can have a fair amount of variability - it is best to be
able to lie a straightedge atop your fretted fingerboard and have the
straightedge hit exactly at the top of your bridge.

Depending on your design, your measurements might be different. But
here is what you need to take into account.

The height of your fretboard (mine is exactly 1/4"). The height of your
bridge (mine is exactly 3/8"). The height of my frets above the
fingerboard are very close to 1/16". If you take all that into account, you
will find you need an extra 1/16" on top of my fretboard + frets to equal
3/8". That is why I want my upper bout to angle itself to a point that is
1/16" above the soundboard at the bridge location.

With a 28" radiused top, I get very close to having the upper bout
pointing where I want. You can always do what Paul suggested and place
a shim - but I think what makes the neck-body joint look great is when
you have the angles figured out beforehand - it gives the fretboard a
much more solid look when viewed from the side.

Hope that helps. If not, keep asking and one of us will eventually have
the answer you are seeking.

--
SimonSimonF39030.6652662037

   As pointed out by others , the geometry should be such that your line off the fingerboard to the saddle location , will vary from guitar to guitar and experience will help.
   I use this formula
   At the point of the saddle location per scale length using the neck without the fretboard I want a 1/16 to 1/8 off the top. Using a standard fretboard thickness .220 this will let you use 3/8 bridge. I use a stock Martin bridge ( .410 ) and adjust that one I am ready to set the neck with the fretboard so I can adjust for the max saddle height. I like to see 1/8 of saddle if I can.
    I am not so cincerned about the angle as I use standard neck blanks from Martin or Stew Mac. They are usually 1 1/2 from Martin and 2 degrees from SM
John Hall

I know my ways is more work but I have refined it to the point where I start with a 1.5 deg neck angle on the heel end of the neck. I finish the guitar body install the bridge, glue the unfretted FB to the neck. (allow glue to cure) bolt the neck assembly to the body. sand the simi-final FB radius using a Stewmac aluminum FB sanding block so that the plane of the FB at centerline is .06-.08 above the bridge at the front of the saddle slot. Adjust by flossing the heel. Glue the FB extension to the body Check again. Adjust by sanding the FB again with the sanding block. Fret the FB, level the frets. Final Check for a plane defined by the top of the frets to be .095"-.13" above the bridge at the front edge of the saddle slot. I like this way because having the bridge installed gives me an absolute that will not change.

now this is for a 25.4 scaleMichaelP39030.6955439815

I guess there is more than one way to skin a cat. I really liked the FB extension I saw on another thread on a ( I believe) L-00 picture for Hesh. Sure brings alot of questions into the equation,at least for me. I'm looking to get away from that "14th fret hump". or a bad fit with the FB and soundboard. Thanks guys! CLinton

Clinton The 14th hump is the reason I settled on my process. I use to fret prior to finial neck set but would get the hump about 50% of the time. By attaching the neck and glueing down the fretboard extension and fine tuning the FB/Bridge relationship by sanding the fretboard to proper height, then freting I never get the hump.

Michael, how do you fret? Tap, press? How do you handle the frets above the 14th?

press through 12, hammer through 18, press the rest with Jaws 2