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Okay, silly elementary question...when you guys glue a box together what touches the back at the neck block...the whole surface of the neck block, or just an area the width of the linings? It seems that just gluing the width of the linings would free up the back plate, but maybe at a cost someplace else...?

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http://www.presnallguitars.com

Any takers? I'm reaalllly curious!

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Michael, I know you're there...I can hear you breathing!

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OK...I'll go first. I glue the whole surface of the block. When sanding on the radiused dish the angle that it establishes provides a uniform surface and angle for the plate to be adhered. I just think it makes it stronger. My other reason...it looks nicer.JJ Donohue38743.6009143519

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

OK Im here

I use a radius sanding dish, all of the neck block is sanded to this radius and makes full contact. The back is to be somewhat active but near like the top. I would think that by introducing a step to give the offset you are refering to would just inpart a weak spot in the back at or near it's greatest load bearing area.

Spread the load and save the toad

gee I wish I could type MichaelP38743.6087615741

Larry,

Of course I am new to guitar building but I have done a bit of research. Another reason to glue the entire block is to help lock the entire assembly which supports the neck angle you have established, which should increase the length of time between neck resets. I have seen many of the OLF'ers further supporting this neck block by using carbon fibre rods attached back to the sides.

you and me both Michael on the typing thing

ShaneShane Neifer38743.6140162037

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Canada

My thoughts too...I just had that idea running thru my head late last night...and I thought I remembered Cumpiano back in the day saying tap the back at the neck and tail blocks, listening for a hollow tone indicating that the block ISN'T touching at the neck block/back...but, I can't find it now, so I probably am just an idiot...

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Full contact for me. Although, I chamfer the end block to the width of the linings.

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Lance@LuthiersForum.com

Bad thing is Shane, I work a computer for a living MichaelP38743.636875

Stronger, too, with it glued to the back, idn't it? Otherwise, the same force that wants to pull the heel out of the block is carried by the lining. burbank38743.6473263889

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now known around here as Pat Foster
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Full contact. The headblock firmly attached to the back is one of the most crucial joints on the guitar. If it's not fixed, your neck's going to want to move around.

'Slipping' this joint, after all, is an acceptable way to re-set a neck on cheap guitars.

Mattia, that's interesting...elaborate on that "slipping" the joint at the back and headblock...I think I see what you're saying, but I'm not real bright sometimes...

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Full contact, and I know it is absolutely crucial for classical guitars as there is very little else holding the neck on. The top is glued on the neck, but otherwise, the neckblock is it. The sides are not glued into the spanish heel. The neck angle is also set by how the block is glued to the back. For classical construction, one way to set the neck is to get the neck at the appropriate angle, and then glue the center reinforcement strip right up against the neck block so it holds the neck at the correct angle. If the neck block wasn't glued, there would only be an area of about 2 square inches on the top holding the neck in place.

Cheers!

John

Larry: check the MIMF or Frank Ford's site for details, or wait for someone with more knowledge to tune in

My basic understanding is that you heat the glue joint between back and block, enough to let the piece 'slip' under tension into a position you'd rather have it.

Odd man out AGAIN ... I bevel the bottom of the neck block to the same width as the linings. 14 years worth of guitars with narry the first guitar needing a re-set. Martin is doing the same thing now on some of their models, hmmmm? If there was structural issues and possible re-set problems I don't think you would see a large OEM shooting themselves in the foot.

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tim...
http://www.mcknightguitars.com

Larry, I think your quoting Bill Cumpiano wrong.
He says to tap at the headblock to make sure there IS NOT a hollow sound. It is supposed to sound solid assuring that the headblock IS making full contact with the back.

I'm suprised to hear people beveling their neck/head blocks. Tail blocks I can understand, but not sure I see the advantage of doing the neck block.

Sure, more vibrating surface, but possible structural tradeoffs? You'd still have good triangulation between the sides and top, so maybe it's a non-issue.

Personally I like a rigid upper-bout and like the extra contact (torque resistance) of a Spanish heel.

   I would advise gluing the entire surface of the neck block to the back since such a load is resisted there. With the strings pulling the neck, the stress on that joint is tryng to pull it out at all times. Over time, the arch i the back can actually be pulled flat by those forces and becuase of it, along with a few other common movements that take place, the need for a neck reset becomes obvious.

   I would look to builders who are building guitars that are ending up in the hands of players for advice and information. A book is a great resource, but some of their authors just don't have the guitars in the marketplace to back up their claims or prove their methods.

Regards,
Kevin Gallagher/Omega GuitarsKevin Gallagher38746.0259027778

Colby, you're probably dead on about the misquote...for Bill to have said that didn't make any sense, so it's most likely me...every guitar of mine to date has the block angled to profile in the radius dish for full contact...I don't plan to change, I just got thinking about the possibilities a couple days ago...but the illustration of the neck heel always wanting to be "pulled out" by the string loads is vivid enough for me...

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Martin is doing the same thing now on some of their models, hmmmm?

They are doing it on their bottom-end models to save assembly time. They also counter it with an engineered top brace system that is very well fitted and precise.

I believe the vast, vast majority of anyone you speak to will tell you that you are following the wrong lead on this one.

You think you're gaining something by freeing up a bit of the back? I'm a "details is where it's at guy", so I'll bite.
How about making a wedge to fit in that gap, precisely, to make it think it has a full block(no bigger, no smaller), and passing it around at a gathering for everyone to hear it, then removing the wedge(attach a string to it so you can yank it out without even changing the tuning on the guitar) and see if anyone can hear a change. You can even have someone play it and yank the string to pull it out to see in real time what the change is.

"They are doing it on their bottom-end models to save assembly time."

If it is such a saver of assembly time please explain how it's timesaving (to the process as a whole) to add ADDITIONAL manufacturing steps [& material] by:
- adding another machining step to cut the neck block bevel
- adding a neck/fingerboard extension to the neck block
- mortise the FB/neck extension to accept the two additional diagonal braces
- manufacture two additional braces that have at least 5 more manufacturing steps vs. the "traditional" rectangular neck block & sound hole braces?

In my irrational path of thought it doesn't seem to be more time saving or cost efficient for a bottom end model.

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tim...
http://www.mcknightguitars.com

Wow! I didn't mean to start anything here...just had a thought about the neck block at the back...I once forgot to go back and bowl sand again after putting my linings in, and glued on the back! Went back and took it off, bowl sanded and put it back on... . It just struck me one night, what may've happened if I left it...good, bad, or indifferent...I didn't know Martin was doing it...between that and the supergluing bridges on thing at Larrivee it's a wonder they haven't come up with a "just add water and shake" guitar!

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f it is such a saver of assembly time please explain how it's timesaving (to the process as a whole) to add ADDITIONAL manufacturing steps [& material] by:

It's a time saver because it saves time in the dish, which is hand time, IE: man hours. Build 80,000 guitars per year, and 10 minutes of hands-on time per guitar becomes 13,333 HOURS of wages. At maybe $15/hour for the bottom guy working at this job, that is just under $200,000, but add benefits, worker's comp, etc... to the cost, and that 10 minutes costs around $300,000. THAT is where saving nano-minutes in manufacturing comes into play. Big numbers.

Apart from the bottom bevel, everything else was already in place years ago. So, they now take 8 seconds more, and cut a bevel on the bottom of the blocks, and save many minutes in fitting the back. CF the fourth pockets the savings...

Listen, you like how you're doing things, fine. Go ahead. You understand the risk VS the gain, even if you don't want to study if there is a gain(easily done and demonstrated with any of your guitars if you care to see), and you are obviously willing to accept it.

Me, I've seen enough old guitars with flat, non-bellied tops that needed a neck reset to know that the neck block and back area do indeed deform, so I'm not going to take anything away from that area, especially if I have to make it up by beefing up the top instead. But you go ahead, it's your right to.

Time will tell. I'm about 20 years younger than you, so I'll see for myself if they stand the test of time or not. We'll discuss the results 80 years from now while looking down upon the next generation, building formica guitars   

[QUOTE=Mario] At maybe $15/hour for the bottom guy working at this job, [/QUOTE]

Uh, those must be Canadian dollars.    I doubt the grunts on the floor are even clearing $10.00 (probably much less in California shops), though I'd be happy to find out I'm wrong.

Really? You can get $12-14/hr up here pumping gas. A bottom guy in a sawmill here gets $22-23/hr, and the papermill guys will start their toilet cleaners at $25/hr... A guy with a grade 3 edumacation who works his way up the line of prograssion will earn upwards of $50/hr these days in a paper mill(I know of a few who can barely write and who earn this much)

I thought I was being a bit low on my estimate of what a guitar factory would pay.Mario38744.6688425926