Official Luthiers Forum!

I have attempted to design an adjustable neck that enables me to alter the action by using a radiused slide within the neck block. I haven't perfected the design but my assumption was that if the raduis was referenced to the nut (centre of the circle) I could maintain the scale length when I changed the action. Am I heading down a blind alley? Any thoughts?

So a cam more or less that raises or lowers the action. Am I right?

It would seem to me that unless the neck was on some sort of a guide track that kept the heal end of the neck in a constent plane relationship to the body, this would tend to change the set-angle as it raised or lowered the neck. Also any change in the height of the neck in relation to the saddel will change the string length some there by affecting the intonation.

I have seen adjustable necks. The Antarctic expedition guitar comes to mind. But the intent with them was to adjust to the changes the guitar went through due to climatic change. In other words the adjustments were meant to bring the guitar back to ideal set-up as it underwent shrinkage and expansion with the climate.
MichaelP38785.464224537

I don't exactly follow your design idea but ideally you would keep the 12th fret stationary and allow the neck to rotate on the pivot point. That way your string length is unaltered. If you set the intonation at the desired action and maintain that action thru changes in humidity by adjusting the neck angle then the intonation should also stay correct.
I guess

_________________
Tickle your guitar daily, and it'll tickle you back.

I was stimulated to see if there was a solution that allowed for different playing styles without adjusting the action at the saddle.
My initial working model had a sliding mechanism that the bolt-on neck would fit into. But that became a little complex and appeared to be more inclined to move out of line under tension. My second idea had two radiused grooves that would lock the neck into position but allow some adjustment using an adjustor through the fretboard or soundhole. I had assumed that if my slides were radiused with reference to the nut as the centre of the circle this would avoid issues of intonation. Perhaps I have made a big assumption about that! I will post a picture when i get a chance and you guys can give me your opinion.

OK it took me a little while to get that but it sounds like that might work. So your radius would be half of the scale length and that should keep the 12th fret in the same location (distance from the nut and saddle) thruout the rotation. It sounds good to me and you just set the angle you want and tighten it down. That is really intriguing. I have also given this some thought but your idea actually seems to be the best I have heard. There are always issues that come up such as supporting the fingerboard extension over the body but it's not a showstopper. It may take a radical twist to solve that but your adjustabe neck is already a radical idea so go for it and keep us posted.John How38785.5967476852

_________________
Tickle your guitar daily, and it'll tickle you back.

Im not sure im following you guys at all But have you seen Jeff Babicz adjustable neck?

_________________
Support the OLF! Bookmark our STEWMAC link Today!
Lance@LuthiersForum.com

Has anyone had a hands-on with one of these Babicz guitars? Looks like he re-invented the wheel, but is it still round?

_________________
Give me 50 cents worth of regular.
Check my oil too, if you don`t mind,,,

Remember as you change the string height, you change the intonation.

_________________
Dave Bland

remember...

"If it doesn't play in tune...it's just pretty wood"

Right you are Dave so an adjustable neck angle really should be used to maintain the same as original action. In other words, set the intonation at your desired action and just adjust the neck angle as required to maintain that. Of course if you want to raise the action for slide work the intonation is not required because you are intonating as a player.

_________________
Tickle your guitar daily, and it'll tickle you back.

Perhaps, something like this would help keep the neck aligned. The two aluminum bars are buried in the neck, and aligned parallel to the neck, body centerline.

CrowDuck

http://www.michelettiguitars.com/Images/Bolt-on_Under.jpg

_________________
Chris Nielsen
Soquel, CA.

It's beginning to sound to me like you guys are headed toward the Taylor articulated neck. Making the neck to body joint the pivot point? They do it with shims but you are thinking alone the lines of a easy mechanical adjuster? Maybe I'm way off base. It has happened before.

_________________
Joe Beaver
Maker of Sawdust

A simple mortise and tenon joint should keep things aligned pretty darn well, I'd think; I'm planning on doing a Doolin-style joint, also inspired by Mark Swanson's adjustable neck guitar. It's got 2 bolts (top one to snug things down, bottom on to adjust angle) and either two or three set screws bearing on small bits of brass rod epoxy'd into the heel; two up high, the pivot points (set-screws allow minor intonation adjustment), the third one I'm not sure is necessary at the bottom, below the angle adjuster, to 'lock' that in place. Only practicable way to adjust the darn thing while strung up (Sort of the point) would be some form of allen-key-on-a-rod that can get poked in via the endpin hold. Or an access panel.

I saw the Babicz adjustable system at Healdsburg. They did a seminar on adjustable necks that also featured Mike Doolin and another builder whos neck heel was actually suspended from the body by bolts.. the heel didn't even touch the guitar(I can't remember who it was) Most of it was over my head but it's an interesting idea. The Babicz design is super easy to use and the guitar stays in tune when adjusting the action.

Babicz has actually patented his neck pivot.. or I guess it should be called a slide, the neck angle is fixed. Thats something to keep in mind. Mike Doolin on the other hand seems a lot more open with his, he mentioned he was trying to get his heel design published somewhere before he would release it on his website. Both have enough info on their websites to imitate their design or get enough direction to find your own way.

_________________
CVT Inc.
A tour of our shop (Somewhat outdated)
My Personal eBay profile. BCWoodBug

I have an adjustable neck Hofner, from 1972 if I remember right. It does not have a heal, it looks like bolt on electric, but it has a hook that comes up from the seat and is adjustable by a screw which sits where the heal would be. The screw is reccesed about 1/2 inch in a hole. It works ok, there is a certain amount of twist that it can get but it never has given me any trouble. I could shoot some photos tomorrow if anyone wants to see it. It was a cheap guitar, nothin special, but it was my first.   
Mike

Mike,

I'd like to see photos of that Hofner. Every little bit of info helps.

CrowDuck

_________________
Chris Nielsen
Soquel, CA.

I'll shoot it,, I mean them in the morning..

I'm working on an adjustable neck design myself. I'd be very inerested in seeing photos of what you're doing, Tim. I can't picture it from your description, but it sounds intriguing.

_________________
Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Not a problem Todd. I will post a picture when i get back to the home computer

Doolin's design 'floats' in a cavity, bears only on a few points, maybe on a tenon as well. I'm still impatiently waiting for the GAL publication that's been in the works for, well, about a year now :-) Fleischman uses a free-floating adjustable neck, I believe, modelled on (I think) Overholtzer. Rick Turner's done a number of instruments in that style; visible gap between body and neck, adjust right there at the heel.

Mike Doolin's very much a proponent of the system, and from what little contact I've had (i.e., I sent him an email. Ahem.) he seemed to be very glad that more people were trying out adjustable necks.Mattia Valente38786.0627199074

Mattia,

I was lucky enough to print off Mike Doolin's adjustable neck block design when he had the article up on his website. Very clever.

I have done 2 adjustable necks now and am in the process of doing the third one all loosely based around his design. His design has the bottom bolt that adjusts "tensioned" so that it holds against string tension as you adjust it. This is clever but I found it harder to build and take the neck on and off with this system so have done an adaptation. This is my normal mortice and tennon with 2 bolts/barrel bolts holding the neck and 3 adjusting bolts. 2 on either side of the top bolt to set intonation/neck alignment. and one in line with the 2 neck bolts at the bottom of the heel to adjust neck angle. The 3 adjusters have corresponding brass inserts in the heel block and tennon. You can't adjust under full string tension - but as you say this is tricky anyway - and you have to slacken the strings and the lower neck bolt slightly, but I can adjust the neck angle in about a minute or so.

The hardest part with these joints in my mind is the cosmetics of accomodating the pocket that the neck needs to sit in for the adjustability. You no longer have the luxury of the heel cheeks butting nicely against the sides. Working out how to do a normal cutaway is still taxing me. I can see whay Mike Doolin does the cutaways that he does.

The big plus is you can do away with all of the fiddling to get neck angle/saddle height etc. You can dial all of this in with the adjusters.

Hopefully I'll post some pics in a week or so when the current build is complete.

_________________
Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Dave, could you give us a copy of that adjustable neck block design, when you post the pics? if not too much to ask though! Thanks

Serge

This is another reason for you folks to head out to the GAL meeting this summer! Mike will be there, and you can ask him about that neck joint, that's how I learned about it. He had a working model there, and he took all the time I needed to show me how it's done. The GAL is supposed to be running his article on it, we are all waiting for that one.
I built my neck joint much like his design, two bolts and two set screws at the pivot points. You don't need the lower set screw when you see and understand how to build the mounting bolts into the neck block with spring washers holding them tightly, this holds everything in position even when the strings are off or loose.

_________________
Mark Swanson
Swanson Guitars
http://www.MarkSwansonMusic.com

Mark,

Mike's design is very elegant and I understand how he uses the lower bolt only tensioned with the split washers. I am just willing to trade this elegance and ability to adjust under string tension for slightly easier build and neck dissasembly.

How do you design the pocket for the neck with a venetian cutaway and still keep the fingerboard level with the side at the neckblock and with a smooth contour into the heelblock? It's driving me nuts trying to work it out.

Serge - yes I will post pictures of the neckblock when I have it finished - and assuming it works OK

_________________
Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Thanks Dave, very kind of you!

I have closely examined Jeff Babicz's guitars-both the handmade ones he makes and the ones he imports.
I have yet to find a downside!!
They sound as good as any guitar I have ever played and play effortlesly.
The guitars do not go out of tune even with radical changes in action height.
Remember the neck goes up and down-it does not pivot.
As far as the intonation changing at different heights-I didn't notice it-if it does it's just sa matter of quickly loosening two allen head screws on the outside of the bridge-resetting the intonation and re-tightennig them.
Jeff does have a patent on his particular design.