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PostPosted: Tue May 13, 2014 9:15 pm 
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Cocobolo
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I've been building Thinline acoustics for a while now and I have a question about neck bolts. Been looking at other guitars and noticed some bolt on necks are only using one bolt and brass insert. So my question is do I really need to use both bolts and brass inserts for a Thinline bolt on neck? It would sure make things easier.

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PostPosted: Tue May 13, 2014 9:30 pm 
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Koa
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Am curious too.

With a shorter heel and thus shorter tenon, you may only be able to get one bolt in there.
It should be fine.
However, I recommend some cross grain wood for the threads of the insert to bite into.

And a test run. It shouldn't take more than a few minutes to make a mock tenon from some scrap wood, pop an insert in there and see what kind of force it will take via cranking down on the screw to see what gives first.

D



These users thanked the author Dave Livermore for the post (total 2): Tim L (Wed May 14, 2014 9:53 pm) • Duhjoker (Tue May 13, 2014 9:58 pm)
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PostPosted: Tue May 13, 2014 10:01 pm 
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Cocobolo
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First name: Jeremy
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Yea I make all my blocks. It's just simpler that way to me. I have been using both bolts but I have to chisel away some of my UTB's in the middle and cap them in order to get the bolts in and out and be able to use a tool. One bolt sure would make that easier. Thanks for the info that really helped.

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PostPosted: Tue May 13, 2014 11:20 pm 
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Koa
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I use a single bolt on ukuleles but the forces are greater with six steel strings. I use a furniture-bolt with a tee-nut on the inside. I have considered using a dowel-pin in addition on my next project, a mandolin.

Bob :ugeek:


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PostPosted: Wed May 14, 2014 9:05 am 
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Keep the tenon, and mortice a 3/8" brass or steel bar vertically into the heel.
Thread a hole in it to line up with a single 6 mm mounting bolt.
Try a mock up and test that, you'll have a hard time pulling anything out of place before your wrist gives out.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.


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PostPosted: Wed May 14, 2014 7:07 pm 
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Cocobolo
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Ok I had an idea. I don't have a fancy CAD program like a lot of people sorry. I do things the old fashioned way. Any way take a neck and look at it from the side. The headstock to the left and the heel to the right. Now imagine that is all slotted and fit together and you can see through the neck block. All right so add the strings. That's automatically gonna pull the neck forward toward the body. Right. We know this. So what if I put the bolt lower than dead center on the tenon? By maybe a quarter inch. Wouldn't that relieve the tension better and allow it to balance out? Do you get what I'm saying?

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PostPosted: Wed May 14, 2014 7:50 pm 
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Yep, the lower you can get it, the better. I see no reason two bolts should be necessary. The bottom one is in tension, and the sides and fingerboard->soundboard glue joint support the compression force at the upper end. The upper bolt is just kinda sitting there doing nothing.

Look at violins. The tension force is taken by the continuous grain of the back "button" that the heel glues to. Your bolt is taking the place of the button in that situation. Lower = more leverage.

And if you're not already sticking a dowel down vertically through the heel, do that, so you have some continuous grain between your bolt and the pivot point that it's levering against. Plus better grain for the threaded insert to bite into.


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PostPosted: Wed May 14, 2014 8:51 pm 
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Cocobolo
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Excellent thank you!!!!!! Would you mind posting a pic about the dowel bit. ID like to see exactly what you mean. And thank you again.

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In order to make an apple pie from scratch you must first invent the universe.
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PostPosted: Wed May 14, 2014 9:15 pm 
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You axed me to text you.


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PostPosted: Wed May 14, 2014 9:18 pm 
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Oops sorry, trying to read posts and text messages.


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PostPosted: Wed May 14, 2014 9:22 pm 
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This thread has good pictures: http://www.luthiercom.org/phpbb3/viewtopic.php?f=89&t=1834

EDIT: Now that I think about it, the dowel's probably not necessary for a thinline since the heel is so short anyway. But still not a bad idea since it gives the insert better grain to bite.


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PostPosted: Wed May 14, 2014 9:51 pm 
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Cocobolo
Cocobolo

Joined: Mon Sep 30, 2013 12:51 am
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Location: Where Palm trees grow
First name: Jeremy
Last Name: Wood
City: Galveston
State: Texas
Zip/Postal Code: 77554
Country: USA
Focus: Build
Status: Amateur
Cool thank you I get it now.

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In order to make an apple pie from scratch you must first invent the universe.
- Carl Sagan

Check out F.O.F. Custom guitars on Facebook.

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