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I've got a gap of 11mm at the saddle and I was shooting for 3-4mm. Where did I go wrong and how to fix?

The gap is from the top of the saddle to a straight edge held against a fretted fingerboard? Is the neck attached?

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Joe Beaver
Maker of Sawdust

Joey: As Joe says we need a bit more info. Possible photo. Most of getting the neck angle correct is in the building of the box. That aside things can be corrected.
Tom

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A person who has never made a mistake has never made anything!!!

I'll post a photo as soon as I get back to work. My main concern is what's more important, the height of the straight edge at the projected saddle position or the fact that the fretboard meets the body/neck in a manner that is flat.

I just built the LMI dovetail jig. When the neck angle is correct according to the jig the straight edge is about 11mm from the surface of the projected saddle position. I imagine I can sand it down a little bit but I don't know how big a deal this is, what other course of action I could take or if there is some other way to compensate. This is a personal build, so there is no client to be pissed. I need a guitar to play and I don't like the action high. I'll post images for reference tomorrow or Thursday depending on how much wine I have with Christmas dinner

Cheers and Merry Christmas.

Joey: The key point is the height of the straight edge over the top at the saddle position. The fact that the neck does not transition straight with the top can be handled with the mounting of the fingerboard. Looking forward to your picture or pictures.
Seasons Greeting to you and yours also.
Tom

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A person who has never made a mistake has never made anything!!!

The thing is to really be sure where you stand right now and have a clear picture how to proceed. Early in my 'building career' I have been guilty of jumping off to soon after discovering a problem only to make things worst.

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Joe Beaver
Maker of Sawdust

I'm still a bit confused on how to proceed with this neck joint. If I make it so that the neck and the soundboard meet so that the fretboard (straight edge at this point) sits flatly through the transition from the neck to the soundboard my gap is 11mm. If I'm not mistaken most people shoot for 3-5mm???

I haven't built the saddle or the fretboard yet. But If I move to the next step and fit the neck accepting that gap, can I compensate for it with a higher saddle, thicker bridge and thinner fretboard?

Or should I disregard how flat the transition from neck to soundboard is in order to achieve a smaller gap?

Or should I compromise between both factors and lessen the gap to about 8mm and compensate the remaining difference by speccing the remaining parts accordingly?

Thanks for the input! It's times like these that I wish there were a local builder I could hang out with for a couple days.

I posted a response before I got to read this. I think it may answer my question somewhat. In reading your post I realized that I am a dumb ass. I added a radius to the head block extension that meets the UTB when I "drove the bus" to radius the kerfings before fitting the top. I also put a 28' radius on the UTB like a dumb ass as well.

So now I suppose I should flatten the upper bout and try to correct the gap at the same time?

What Todd said. Plus there are different ways to do this, fit the neck but for me what I want to see regardless of if the upper bout has been flattened or slightly radiused is with the fretboard in place, if even temporary, a straight edge on the fret board just skimming the top of the bridge that you intend to use and with the bridge properly located. Some folks over or underset the necks slightly more but this works for me.

You can make a pseudo-birdge of the exact same height and figure out where it needs to be located to do the straight edge test.

Above all and I have dealt with this many times with newer builders there is a perception with some and their understanding of how necks and bodies go together that if one builds to a 1.5 degree neck angle everything will fit perfectly. Wrong...... Necks still have to be fitted and we call it "flossing the cheeks...." which reminds me of a store just down the block from our shop called "Bongs and Thongs..." Not kidding and Joe White noticed this store today and commented while visiting us..... College towns are great..... especially in the summer.....

The neck angle is critical though, very important and can be a deal breaker come set-up time if this is not done correctly. Using a taller or shorter saddle won't do and can create other issues from splitting the bridge (taller) to poor break angle and lack of volume (shorter).

The first couple of necks that I had to fit took me more than a day each but once I started understanding how to read the neck joint it got way easier.

A couple photos Joey could go a long way to helping the crew here understand where to help you?

Thanks for the comments fellas, I'm about to get back to work as I think I have a better grasp of what needs to be done. I'll post some pictures in a few before and after I make a few adjustments.

I have not built the fretboard or the saddle yet, so I suppose I should at least get that knocked out as well before getting too far ahead of myself.

Thanks again and happy holidays.

http://www.youtube.com/watch?v=L3YJh9OT4mw
this can help. This is all about geometry. I am now on 173 and I learned a few things that I share in the video. You need to get the geometry right to make the neck set perfect. Thing ACE Angle Centerline and Elevation. No matter what the neck joint you still have to maintain the proper neck angle , and center line of the neck to the body. If you don't think about this when the sides are in the mold , you can make getting that neck angle right difficult.

Here is how to prep the sides. No some use an arched traverse brace some don't. I use the flat but I also use the older style Martin brace, it has the same amount of wood but is stiffer.
http://www.youtube.com/watch?v=LrgRKKsxL-M

I don't over radius the top and pay attention to how I verify the created angle. When the body is done you can then true this area with a sanding block that rides the neck so the created neck plane is dead true.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

Great pickguards for sure. I can also tell you that the better you watch on the set up the less work to set a neck. My last few went is without doing anything. Like anything else , the more you set things up in the prep stage the easier it is in final assembly. I find that .094 is my target. This gives me a final out come of string height .500 . I set my bridge to .350 in the center that gives me a nice through saddle of .150 in the center .
Also I set the intonation to 3 cents flat on initial set up ,, as the guitar settles in about 2 weeks the intonation falls in perfect and I can do all final compensation on the saddle with room to spare.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

John, just watched all 5 of your dovetail videos. Good stuff!!! thanks for posting

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Joe Beaver
Maker of Sawdust

Hi John,

Haven't been on much in a while but have a couple on the bench…say, are you saying you do the initial intonation as normal except that you aim for 3 cents flat at the 12th fret, fretted?

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http://www.presnallguitars.com

yes on initial set up . What is going to happen , the top will raise and the bridge will slightly rotate. I use a 3/32 saddle and if you miss the mark the compensation on the B can let you with a thin spot. The 3 cents will fall in the stresses take hold. If you use a 1/8 saddle you can set up right on the front and you have room for later compensation. T

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I've got the fretboard thinned and radiused, the dovetail is just about flush and the bridge is shaped.

The gap from ruler to top of the saddle with the fretboard in place is 0.175" (4.45mm).

The thickest part of the fretboard is about 0.193" (4.9mm) with no frets yet.

The saddle is about 0.270" (6.9mm)



Is this acceptable or should I make some adjustments? The lower bout has really flattened out below the x and my bridge placement has moved a hair again due to other problems that have since been solved. I feel like I'm playing that bash the gopher on the head arcade game! Lol

Yes I meant bridge, not saddle. I'm so thoroughly con fused at this point. On paper everything should have worked out. I flattened the upper bout and got the 3.5-4mm gap as recommended by Robbie O'brien, made the bridge thicker than the fingerboard, and I'm still having a 4.4mm gap. I don't get where I went wrong.

Being the middle of winter could humidity be a problem? How is the radius of your soundboard?

It can get pretty dry here in the winter, noticing the garage door and 4 wheeler in the background, I thought humidity. I wondered whether the geometry issue could be humidity related and the soundboard a symptom of that.

Yeah I've all but given up trying to humidify the shop. It's in my garage and the only thing between the shop and the outside is a poorly insulated garage door. I never open the door but when it's -48 outside like it was last week the heater pretty much runs constantly just to keep the garage between 50-55 degrees. I still run the humidifier although it's probably futile but the humidity is usually 22-25% regardless of what I do. I figure- at least it's constant. I wouldn't sell this guitar, for me it's about the experience of the build and having something to play.

The geometry of the top where the X brace is still has a nice dome. Behind the X brace it flattens right out almost dead flat. I screwed up the dovetail on the first neck, but luckily my plan was for a baritone. It would have been way to low as a baritone and the neck screw up would have made it even worse. So I just changed the scale length from 27.5" to 25.7, shortened the neck with the new dovetail and moved the bridge a bit forward (back up on the domed geometry of the top. It seems like it will work out but first I have to make another bridge.

It's warned up from -48 to 22 degrees. Humidity is now all the way up to 36% in the shop. How long should I let it sit at that level (assuming the deep freeze doesn't return) before gluing the bridge? Once complete it will live in a 40% humidity controlled room in my house.