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I built this jig to the OLF plans. My first and only neck that I cut using it had too much of an angle. I'm sure it is totally my fault, but I'm not sure how I messed up. Here is what I did.
I taped the bridge on the top at the appropriate location.    Next, I put the guitar body on the jig and adjusted it until the body touched at the bottom and on the bridge.










The angle measures at 4°. I'm thinking it should be about 1/2 of that. The top has a 25" radius, my bridge is 0.375" thick.

What am I doing wrong?
Thanks!

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Well, I don't use this jig but unless I'm mistaking you didn't take into account
your finger board and fret height.

I think Tommy hit it right.

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[QUOTE=TommyC] Well, I don't use this jig but unless I'm mistaking you didn't take into account your finger board and fret height.[/QUOTE]
How would that change the angle?

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Steve,
I don't use that jig but I know that in order to transfer the angle to the neck you need to do it without the bridge on.

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

That jig is designed to accurately transfer the angle ralation from the top to side onto the neck joint, if you use the bridge that angle will change dramatically.
try it again without the bridge on and that should transfer the exact angle.

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

Hey Steve

Look at the graphic I made. Points A and B stay the same, but when I move the vertex (point C, where the lines intersect), do you see how the value of the angle changes? I'm not sure how Paul designed his jig to work, but whether the fretboard is on or off will change the point of the vertex, which changes the value of the angle. Same goes for whether or not the bridge is on or off. That will change the value of the angle by moving point A in this case. Try to find out what needs to be on or off for the way Paul intends the jig to measure angle.

Because the Aluminum bar rests on the body, it represents the bottom of the fingerboard plane. So, yes, you need to reduce the thickness of your hypothetical bridge by the thickness of your fingerboard. Then you'll have a good angle.
Did you build this from the OLF plans? If so you'll notice that there is a bolt going through the aluminum bar at the bridge location. It's there because you can't have the thickness of the bridge in that location. So reduce the thickness of the bridge by the fingerboard thickness and that's how much bolt you should have sticking out.

Steve, great pics.

I don't have the jig either.

But immediately saw your dilemma...

I have the Dick Boak booklet which came with my only Martin Kit.

It shows this angle and says to shoot for 1/16th inch at the bridge location with a straightedge laying along the bare neck top join.

This follows what everyone is saying, no bridge needed at this point.

I hope you can salvage that neck. I like Paul's jig thingy and may build one myself if I switch to MT join.

The next one will be perfect.   

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I think this previously posted image shows the bolt?

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I just would look for a 1/16 - 3/32 gap @ the bridge location. That always did the job.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

[QUOTE=Pwoolson] Because the Aluminum bar rests on the body, it represents the bottom of the fingerboard plane. So, yes, you need to reduce the thickness of your hypothetical bridge by the thickness of your fingerboard. Then you'll have a good angle. [/QUOTE]My fingerboard is .250", my bridge is .375". What about frets and saddle?


[QUOTE=Pwoolson] Did you build this from the OLF plans? If so you'll notice that there is a bolt going through the aluminum bar at the bridge location. It's there because you can't have the thickness of the bridge in that location....... [/QUOTE] Yes, it is the OLF plan. This guitar is a baritone, and I build short scale along with more standard scales. I was thinking that it would be good not to add the bolt and holes in the bar but put the bridge (or appropriate spacer) in the proper place instead. Does that make sense?

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

I have been building following the Frank Finnochio method of making the upper portion of the upper bout flat at about 1.5°.
This is my first attempt at making the entire top radiused.
In the picture below, you can see the curvature against the straight bar.
It touches at the rosette but not at the top of the body.
Should I make the portion under the fretboard flat?
If so, do I do that before or after using this jig to rout the neck?




I repeated the measurement with a .125 spacer.
The measured angle changed to 3°.
This still seems high to me.



Thank you for your help.
I hope this is helping others also.

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Steve remove the bridge and replace with a 1/16" spacer. Should get you where you need to be.

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[QUOTE=Bobc] Steve remove the bridge and replace with a 1/16" spacer. Should get you where you need to be.[/QUOTE]
Is this what most people do even for a baritone or a short scale?

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

[QUOTE=SteveS] [QUOTE=Bobc] Steve remove the bridge and replace
with a 1/16" spacer. Should get you where you need to be.[/QUOTE]
Is this what most people do even for a baritone or a short scale?
[/QUOTE]

Steve, it doesn't matter. Either one. Don't worry what the actual angle is.
You're trying to get the plane of the fingerboard to align with the bridge
properly, regardless of the angle.

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Mike

"The Dude abides. I don't know about you but I take comfort in that. It's good knowin' he's out there. The Dude. Takin' 'er easy for all us sinners. Shoosh." The Stranger

OK - I used a 1/16' spacer. Everything looks right now. Thanks!

This is my first attempt at making the entire top radiused.    I have been building following the Frank Finnochio method of making the upper portion of the upper bout flat at about 1.5°. This took care of the gap problem under the fretboard at the neck joint.

What is a good way to deal with that gap? You can see it in the picture below.
Thanks!

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Steve, I'm going to give it a shot here, just thinking as I write, I hope this is understandable.

It looks like you are either going to have to taper the bottom of the fingerboard extension or sand away a bit of the top near the rosette/soundhole, essentially creating a taper from soundhole to neck joint. Or, you could make your bridge thicker which will allow you to increase the angle of the neck a tad and have the fretboard extension drop a bit near the neck joint taking care of the gap..... If you choose to sand away part of the top where the fretboard extension lies this might help.....attach the neck to the body at the proper angle, grab a piece of straight/level wood approx. 14-18" long x 3"-4" wide, attach about 6-8" of sandpaper to it at one end, then slide the board on top of your neck(without fretboard....the motion is from nut to bridge), keeping the sandpaper off of the neck and on top of the area where the fretboard extension will go. Watch carefully as you go until the board rests perfectly flat on the neck and the top where the fretboard extension will lay, it doesn't take much so go slowly. With a wider board it will flatten an area wider than the fretboard extension which is good, otherwise you will sand a groove in your top. If the top has some radius here it will help the process if it is flat then you may need to widen your sanding path to taper the top from side to side eliminating any possible grooves. One note, I cannot tell how big the gap is but remember that will translate into an amount to be removed near/over the rosette, your rosette needs to be thick enough or you could sand through....I doubt your gap is that large, if it is I might opt for fretboard tapering or a thicker bridge.

Greg

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Gwaltney Guitars

Thanks Greg. I don't think a thicker bridge is a good idea as it would make my string height above the soundboard at the bridge more than 1/2".
The gap is small, probably .025".
Peter M talked to me about the sanding method you described. That makes sense to me.
What if I mark the top where the gap is with pencil and sand flat underneath the fretboard to when I just start to remove the pencil mark?
It does worry me that I might make a groove, but my top is thin so I don't want to sand a large area.

Perhaps Frank's method is easier......

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Hey Steve,

My experience with this operation is that it is very difficult to get a dead flat landing zone unless you use some sort of long, flat piece of something riding on the neck, even then I constantly run a straight edge along the same plane to check the progress....I would NOT try to hand sand this area, that is, just try to block sand off pencil marks without registering off of the neck plane, it's really tricky. I think with a .025 gap you'll be O.K going this route, just remember you will sand a groove if you just sand below the fretboard extension, it seems to work/look a bit better if you spead the sanding a bit edge to edge as well. Good luck Steve.

Greg

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Gwaltney Guitars

Steve, Hesh gave a good tutorial on what he does here. Maybe this will help.

I just make the upper bout flat when truing up the linings before the top goes on.

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