what do these heel bolts do

[tomana]

was watching a video about Making a Greenfield Guitar and when he was getting set to glue the neck to the body I noticed two bolt-looking things in the heel. Anyone know what they do, or are for?

[fazool]

I saw that too and couldn't figure it out either.....

[gitarro]

Just look at the cleanness of the fit and finish and exact craftsmanship of wood on display in that shot!

[Simon Fay]

They are dowel bolts. The bolt attaches through the headblock from inside the guitar body. This is a pretty common method of attachment for bolt-on necks. They are also used commonly in furniture building. This photo should explain their function.

[nacluth]

I'm not sure of Greenfield's construction methods completely, but my guess is that they are threaded inserts like are found in furniture construction. They are inserted in a hole perpendicular to the bolt hole. A threaded bolt would come in from the heel block side internally and fit into the insert. On a "put it together yourself" piece of furniture, you could use a screwdriver to hold the insert straight while running the bolt in. My guess is they probably glue or mechanically attach these inserts to keep them aligned.

If this is not the case from my brief observation I would like to hear as well.

edit: Simon beat me to it and with a picture!

[fazool]

Ah yes - I've seen/used those in furniture assembly - didn't recognize them on a guitar. Very clever.

[tomana]

ah, now I get it. He glues the fretboard but the neck is a bolt-in. Thanks for the replies and yes, his craftsmanship (and Olson, etc) they are the superstars of guitar making

[justonwo]

Like on Ikea furniture! Ha ha.

[Pat Foster]

I've heard them called barrel bolts. Michael Gurian used the method in the 1970s and it was picked up by William Cumpiano and many others.

Pat

[dekutree64]

Yep, Cumpiano taught a lot of us that method via this page http://www.cumpiano.com/an-improved-neck-body-joint

[Jeff Scott]

Originally Posted by dekutree64

Yep, Cumpiano taught a lot of us that method via this page http://www.cumpiano.com/an-improved-neck-body-joint

Thanks for that link, now I can learn about that method. My two Yamamotos use that but I didn't know the source of it until now!

[johnbaz]

Hi

I just bought a hand made acoustic that has a bolt on neck, I saw a slight gap at the heel and thought the neck was coming loose but when I looked through the soundhole, I saw two bolts also so the slight gap at the heel isn't causing a problem!

The action is a little high so I removed the strings and ran a 24" rule along to the frets and instead of sitting on the bridge, It butted up to it, It's about 1.5mm below the top so then I got to thinking that the neck was shaped wrongly when it was made but when I put the 24" rull back on the frets there's quite a large hollow in the centre!
The neck is in relief and needs some back bow so the trussrod need tightening I reckon, I'm hopefully going to find a competant luthier not too far from me to give the guitar a setup and trussrod adjustment (Or whatever it takes to make the instrument more playable!)



The rest of the guitar..






Sorry, I couldn't get a pic of the two large head bolts inside

OOOPS!, Sorry for replying to a years old thread, I shoulda looked at the date first!
Cheers, John