ANZLF Adjustable Neck Joint Group Discussion

Got a new way of doing something? Or maybe an old method that needs some clarification.

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Allen
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ANZLF Adjustable Neck Joint Group Discussion

Post by Allen » Sun Mar 02, 2008 6:28 pm

I've been studying adjustable necks for a few days now, and it seems that just a little bit it is starting to sink in :shock: .

A few differing approaches though. Grant's seems to rely on a spring type washer and bolt tension to set the angle. Another (I think it is Dave's) uses 2 standard barrel nuts and bolts, but uses adjusting screws to set yaw and neck set. This method seems to offer a more robust way of setting everything just so.

Then there is Jeff Babicz's method of just raising or lowering the entire neck, not adjusting the angle. I assume that he has set the neck angle to a happy medium and then allows the player to fine tune to his/her preference. This method seems to have some advantages, but I'm at a loss as to how he goes about attaching a neck firmly enough yet able to adjust hight with just an Allen key.

What's everyones opinion and pros/cons of various methods?
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Post by Kim » Sun Mar 02, 2008 6:36 pm

If I recall discussion correctly, Grant's neck can have those spring washers omitted so I don't think it is about spring-loading the joint but more a pre-tension before the strings go on, in fact I'm quite sure that Dennis left them out of his version with no problem but he would have to confirm this.

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Post by Craig » Sun Mar 02, 2008 10:11 pm

G'day Allen,

I've been studying others designs too and am about at the same stage as yourself. So far I favour Daves design ,as it can adjust the yaw ,rake and neck length ( intonation ), but like you , don't understand fully how the Babicz one works,,,,,,,but I'd like to ! :lol: Hopefully some one will let us both know.

I'm tempted to go for an adjustable heeless design I've been working on. Has anyone got any thoughts on NO HEEL :shock:

Keep us posted on your findings Allen . I for one ,am very interested. A consistant action regardless of weather conditions sounds good to me , and is what I'm definatley going for.


Cheers, Craig

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Post by Dave White » Sun Mar 02, 2008 11:51 pm

Allen,

My method is just an adaptation of Mike Dooiln's brilliant design - I invent very little. I'm of the view that if you are going to make it adjustable then do it so that you can adjust just about everything as according to Sods 9th Law you will have to at some stage. Most of the changes in a guitars geometry that you are fighting against need you to change the necks angle relative to the top plane rather than height and by slight changes in angle you can also get different playing actions for the same saddle height (set to "optimise" tone/sound) so the Doolin/Turner design seems better than the Babicz one to me.

Craig,

The Strat has an adjustable neck angle system with no heel so why not. Tell us more about the design features.
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Post by Hesh1956 » Mon Mar 03, 2008 12:32 am

I wish I knew more about this but I read a few days ago that Taylor guitars have an adjustable neck set-up using shims. Anyone know about this?

The poster of this information said that it was Taylor's way of making the need for neck resets a thing of the past.

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Post by Dennis Leahy » Mon Mar 03, 2008 5:16 am

Hesh,
I believe Taylor bolts the neck on, and also bolts the fingerboard down - no glue. In the players hands, it is not really "adjustable." Later, if the neck angle goes wonky, the Taylar neck can be unbolted (from the heel and top), and tapered shims that Taylor CNCs can be inserted behind the heel and beneath the fingerboard, as necessary, to get the nack angle back to playable. I would be amazed if Bob Taylor sticks with that system, and would expect him to go to a truely adjustable neck sometime in the future.

Craig,
In a heel-less neck, you'd lose that lower contact point to define the adjustable neck pitch. So, I would think you'd need to run a setscrew up toward the neck (near the neck/body joint) to change the pitch. Then you'd either have a hole in the guitar's back (a la Babicz) to get the tool in there, or you'd have to have either just a small neck block glued to the top or a neckblock that looks like a classical Spanish neckblock, empty in the center. Somehow, you'd need to get access to a setscrew head pointing up. (Yes, I can think of a way to screw in and have a mated piece go up, but that would be a machinist's project in itself.) Good or bad, I suspect the heel-less neck would make the neck into a whammy bar to some degree.

Babicz's patented design holds the neck two ways: horizontally, and vertically. It is held horizontally by a trapped slider (see page 5 of the PDF file), and vertically by a bolt. The bolt it trapped, so it just spins in place, and a threaded insert in the neck thus advanced up and down. To me, it is a complicated system, difficult to produce without CNC, and even if it was not patented, I would not attempt it. I also don't like the exposed hardware port.

The one thing I don't like about the butt joint neck (whether adjustable or not), is using inserts. I guess they work OK if you drill up through the neck heel and insert a wood dowel, so that the inserts have something other than end grain to bite into. But, to my eyes (thinking like a furnituremaker), the mortise and tenon with the cross dowel seems stronger and nearly foolproof, so why screw with inserts. (pun intended)

That leaves Mike Doolin and Grant Goltz. I have to say, I had never seen Mike's joint when I used Grant's. They both work, but I do like the added adjustability afforded by the setscrews. In fact, I now know for sure that I can easily hear a difference in intonation when I change the neck angle on my guitar using the Goltz method. So, at a minimum, I'll add upper setscrews to allow me (after a neck angle change) to tweak the string length back to exactly the same as when the saddle was intonated. Then, there is also the added benefit of being able to adjust the yaw (side-to-side) angle of the neck by manipulating a pair of setscrews. That could be a lifesaver especially if the neck block/body joint is off even by a degree compared to the centerline of the body. Finally, there's that bottom setscrew. The Goltz method does not use one, and it still works. However, it might just be the very easiest way to accurately change the pitch of the neck.

In conclusion... (I know, I'm long winded) by the time I add the 3 setscrews to Grant's design, I'm really close to Doolins, maybe even there, in terms of the core engineering. I do like the more graceful heel design (like a woman's high heel shoe), rather than the constant width heel I have seen on Mike's guitars. And, I disagree with Mike's decision to access the lower setscrew from the exterior of the guitar.

That's my $.02

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Post by Allen » Mon Mar 03, 2008 7:11 am

I'm trying to figure out how that screw on Mike Doolin's guitars can adjust the neck from the outside. If I'm thinking this through correctly, the two upper set screws will adjust yaw and intonation, the lower one does the neck angle. Then you use the 2 standard neck bolts to snug everything up.

How can you adjust the angle without first loosening at least the lower neck bolt, adjusting the lower set screw and then nipping up the lower neck bolt?
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Post by Dennis Leahy » Mon Mar 03, 2008 8:56 am

Allen, sounds like you're understanding this the same as me.

As far as I can tell, Babicz's system is the only one where you don't have to loosen bolts to make an adjustment, then re-tighten the bolts.

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Post by Dave White » Mon Mar 03, 2008 10:11 am

In Mike Doolin's old system, the adjustment was on the inside and used the bottom neck bolt that was "pre-tensioned" - trapped inside the neck block against a spring washer so that it pulled the neck out and in when you turned it and it went in and out of the barrel bolt on the neck tennon. I don't know how his new system works and if he has just used the same arrangement with an outside adjustment but there are other ways and you obviously don't have to loosen and re-tighten neck bolts on his new system based on his web-page.

On his Antartica guitar Rick Turner had an outside adjustment system that you can check out here on Frank Fords great website.

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Post by Sam Price » Tue Mar 04, 2008 12:21 am

The two best guitar engineering feats since sliced bread is the carbon fibre inlayed and adjustable neck.

From now on, I will always build my guitars with this feature- as being a guitarist for 20 years has enabled me to see a lot of guitars needing resets; I have an Avalon waiting for one, but as it is dovetail, I am waiting until I feel more confident!!

My current build has an adjustable neck, and the trick I found is to make those little set screws as snug as possible but easy to turn with a hex key.

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Post by Allen » Tue Mar 04, 2008 7:11 am

For the set screws, I've read that most just thread them through the wood. I was thinking that you would have a more positive connection if you embedded and epoxied in a nut. Steel thread to steel thread eases my mind somewhat to this rather critical design feature. You could use a nylock nut to limit the set screws tendency to want to move on its own.
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Post by Dennis Leahy » Tue Mar 04, 2008 10:54 am

Dave White wrote:In Mike Doolin's ...

... you obviously don't have to loosen and re-tighten neck bolts on his new system based on his web-page.
Hi Dave,

I couldn't find reference to that on Mike's site. It does say you don't have to loosen the strings. I'm thinking you could probably tighten the crossdowel bolts without cranking too hard, and that would probably still allow a bit of microadjustment using the setscrews (especially if you are turning the setscrews looser.) But for a bigger change in action, I'd think you still would need to loosen the crossdowel bolts a little bit.

This is conjecture on my part - just looking at the engineering - and I know that you have built a few (which I have not), so actual knowledge trumps conjecture any day.

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Post by Allen » Tue Mar 04, 2008 5:30 pm

Dennis Leahy wrote:... so actual knowledge trumps conjecture any day.

Dennis
I like that Dennis, I'm going to use that the next time I get an opportunity at work. 8)
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Post by Dave White » Tue Mar 04, 2008 6:53 pm

Dennis,

On Mike's old system the adjusting bolt was the bottom neck bolt. I think his new system is the same but with the bolt on the outside going into a threaded insert. The bolt is "captured" in the heel and so when you adjust the allen key it pulls the neck in and out about the top pivots. No need to loosen the strings or any other bolts. The really clever engineeering will be how he has "captured" the bolt in the heel while still allowing it to turn freely for adjustment. Didn't Mike do an article recently about his adjustable neck joint in one of the American luthiery journals? There should be more details there.
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Post by Dennis Leahy » Wed Mar 05, 2008 2:57 am

Dave White wrote:... Didn't Mike do an article recently about his adjustable neck joint in one of the American luthiery journals? There should be more details there.
I'm embarrassed to say I'm not a member of the Guild of American Luthiers (GAL.) My excuse used to be that I'm not a real luthier, yet. (still true) My new excuse is that I would rather buy wood with the money. :oops:

It looks like it is the GAL issue #86 from summer 2006 that has the most recent article on Doolin's (and Fleishman's) adjustable neck systems.

From the photos on that GAL page I linked to, it does appear that there is quite a gap between the end of the tenon and the back of the mortise, and that it is all dancing prominently on the setscrews. (I had visualized mortise and tenon surface contact, with setscrews "at the ready", but that was incorrect.)

From what I can tell by looking at the online photos published by GAL, I would still think that (for the engineering exposed there) you'd still have to loosen the bolts on a fully tightened neck in order to raise the action. That assumes that 2 crossdowels are being used, and no lower setscrew. Actually, I am confused by the photos shown on that page, as it looks to me that there are several different evolutions of engineering shown there. In the side view of the assembled neck, it appears that the bottom cross dowel bolt has been replaced by a setscrew. The setscrew there makes sense to me, as I see that could be used as the main adjustment for the neck angle. If that's an optical delusion, then I would think that one of the spring washers would need to go into the gap between the mortise and tenon, and that the distance between the fully compressed and fully expanded washer would be the limit of adjustability.

Sorry if I'm being daft, but I thought I had a pretty good idea of Doolin's (old) adjustable neck system from hearing it described. Now I know I don't know. I can't tell how he is capturing the bolt on the new system, but I just don't like the exposed hardware (in spite of the apparent ease of action change.)

So you see Dave, a full tutorial on your adaptation of Mike Doolin's "old" adjustable neck system would be greatly appreciated.

Unless I see something to make me change my mind (quite possible!), my current thinking is that I will use Doolin's old system, minus the spring washer, plus the inclusion of a bottom setscrew (evident in Harry Fleishman's photos.) Or, you could call it the Grant Goltz method, minus the spring washer, and plus three setscrews. The bottom line being that 3 setscrews would define the pitch and yaw of the neck relative to the body (and provide string length adjustability, for intonation), and 2 crossdowels with bolts through a (floating?) tenon would only serve to hold it in position.

I am debating whether to also use spring washers, not in the M&T gap, but rather right beneath the bolt head. I'm thinking that might make setscrew adjustment possible without loosening the crossdowels.

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Post by Dave White » Wed Mar 05, 2008 4:40 am

Dennis,

I'm afraid this is going to have to be a "trust me you can adjust without loosening/tightening any other bolts". Mike used to have a photo-documentary on his website of how to make the joint which I printed off at the time - the GAL photos seem to be versions of these. The bottom neck bolt is ALSO the adjusting screw. In the old system it was captured inside the neckblock with a tension washer pushing against the bolthead and against the heel-block. To raise the action you turned anti-clockwise, the bottom bolt came out of the barrel bolt slightly and with the bolt-head pushing against the tension washer and the neck block, the bottom of the neck heel went out (helped by the string tension pull). Turn clockwise and the bottom of the heel is pulled in. The amount off adjustment for a significant change in action height is very small (the barrel bolt does any necessary swivelling) and the top neck bolt doesn't need loosening or tightening. Try taking an ordinary bolt on neck with both bolts tight, now loosen the bottom bolt slightly and see if you can pull out and change the angle of the neck with the top bolt still tight - I bet you can. His new system will be similar but with external adjustment - he probably did this as it's tricky to get to the internal bolt through the strings into the soundhole.

I did my adaptation as I found it tricky taking the neck on and off with the captured/tensioned bottom neck bolt and so added a bottom set screw. This meant I have to slacken the strings to make an adjustment but this is no big deal to me.
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Post by Dennis Leahy » Wed Mar 05, 2008 5:19 am

Thanks, Dave. I feel like I have a better grasp of what Mike was doing, and a better idea of how I want to proceed.

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Post by Craig » Wed Mar 05, 2008 12:36 pm

O.k guys, here's a dirty and rough drawing of an idea to contain the bottom adjusting/holding screw.

Image


The screw is narrowed below it's head to fit in the steel insert. The insert epoxied in place

Your thoughts ??


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Post by Allen » Wed Mar 05, 2008 5:26 pm

That's spooky Craig. I was wide awake all last night thinking about how to do that and thought of something very similar. Seems to me that this is a very viable option. Now I've got an excuse to buy a small metal lathe :)

I just had another thought after I was trying to figure out how to convince the treasurer that I need a metal lathe. Head light adjusting screws on older style headlights (the round or square ones) have an adjusting screw with a recessed collar like that. Worth checking some out.
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Post by Dave White » Wed Mar 05, 2008 7:19 pm

Craig,

Is this a bottom neck bolt "captured" system I see before me :D

There are two essential things the system has to do. Firstly the captured bolt (and the barrel bolt/insert it goes into) has to have absolutely no play in it when in the neck and under string tension - you (or the string tension) can't move it in or out. Secondly you need a really smooth adjustment when you turn the bolt and it moves inside the capture mechanism. If you can machine and assemble the mechanism to do this then you will have it well sorted. There's only one way to find out for sure :D

I'm looking forward to seeing the heel-less ideas too.
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Post by Craig » Wed Mar 05, 2008 10:41 pm

Dennis , could you tell me why you aren't happy with Mike Doolin's decision to make an external adjuster ?

Dave , I'm still thinking this idea through . The fit between the insert and screw would hopefully be an interference fit . It's one element in the design I'm concerned about though.

I have yet another idea I came up with today, which I think may be better and easier . I will draw it up tomorrow and post it.

Allen , I can see it's hot on your mind at the moment too :lol: Would you mind posting your similar idea ? Better hold off on that lathe purchase mate . My next design won't require it.

Haven't had time for the heelless one at the moment Dave :roll: :lol:


Cheers ,Craig

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Post by Allen » Thu Mar 06, 2008 6:43 am

Mine was to use a thick washer with a slot cut in the top like your system. I had though that It could be used in a but joint system were the washer would be epoxied into a recess in the butt side of the neck after the neck was finished.
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Post by Dennis Leahy » Thu Mar 06, 2008 9:16 am

Craig L wrote:Dennis , could you tell me why you aren't happy with Mike Doolin's decision to make an external adjuster ?
Cheers ,Craig
Hi Craig,

Mostly just the aesthetics. And, frankly, that is being picky, because it is not obtrusive (especially on a "flat" heel. It might not look as good on a pointy heel.)

Allen, as long as you're getting out the metal lathe, maybe you could turn the exterior flange into a strap button with a hollow center?

I guess I kind of like the idea that you can have an adjustable neck, and show no hint of it. I like the truss rod nut to be faced towards the sound hole too - just one more spot where hardware is hidden. I would not want someone to hide the tuning machines within the box, however. :lol:

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Post by Craig » Thu Mar 06, 2008 12:47 pm

Here's version 2 of the Lawrence bottom neck bolt captured system.

I already had the strap button idea on my plan , but I see Dennis' post above beat me to the punch. I've taken your nyloc nut idea for the HEADBLOCK though Allen. I tested them out this morning and I can't get any to and fro movement from them, plus they won't undo themselves.

As you can see, I want to keep this as simple as I can . My first version rely on the interference fit between the screw and plate remaining an interference fit . It may do just that, but just in case that fit started to gain a little play after several adjustments ,I've come up with this ( more simple ) idea.

If any play should develop with this version 2 system , and I think it would after a little wearing in, it can easily be taken out by unlocking the two locking hex. nuts and taking up the slack.

In the left of the picture you can see these little nylon type washers. I got these from Bearfast some time ago. I don't think they are Nylon actually. He did tell me when I got them , but I forget what they are called. They are only .75 mm. ( .03") thick , hard ,and designed to slip. I'll try and find out what they are called later on. They allow for firm yet smooth tight operation. I'm thinking of maybe a steel or brass washer in front of them.

For the top two pivot adjusters I still like the set screws , but into metal threads not wood. I was thinking either T- nuts or Allen's Nyloc nuts fixed and let in to the front ( heel side ) of the headblock. Barrel and bolt in line between them.


Image


Your critique is most welcome and is in fact my aim


Cheers, Craig

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Post by James Mc » Thu Mar 06, 2008 5:50 pm

I've been following this thread with interest because in the tropics an adjustable neck would be a very good thing. I put on my engineers hat and gave the topic much thought and consideration last night while drinking beer. My conclusion was that there are so many ways it could be done it was making my head spin. You could use worm gears like those in a guitar tuner or cog and track system like the hight adjuster on a drill press. You could cut a triangular wedge out of the neck block and drill a hole thorough the middle then put it back in the block with a bolt set up so you can drive the wedge in or out to provide lift. Rollers with off center shafts.... it goes on and on. At the end of my deliberations I came back to the KISS principle and the fact that I want any guitar I build to still be around in 100 years. I also want it to be as low maintenance as possible, and as an engineer I wouldn't trust any system that didn't need to be tightened after adjusting to last 100 years without having to replace parts.

Now, I’ve been out of the game for 20 years so the fact that bolt on necks are no longer a novelty found on experimental guitars, but have actually become popular was news to me. I’m not really across how these bolt on neck joints are being done, but if they have a parallel slotted joint then wouldn’t the easiest way to adjust the neck be to slot the bolt holes in the neck block so you can loosen the bolts and slide the neck up or down as required. If you want to avoid removing the strings to loosen the bolts maybe you could make an allen key with a universal joint that can slip between the strings.

My old Fender Villager 12 string had a heel-less screw on neck. It was a very simple set up. Steel plate on the back or the guitar with four countersunk screws going through it and the neck block then screwing into the underside of an electric guitar neck. It was a shocker for the action changing with the weather so I made a few shims out some scrap Indian RW with two slots to match the screws. One was 2.5mm thick the other went from 1mm to 2.5mm. All I had to do was loosen the screws and slip in the shim that worked best for the current amount of wonk then tighten the screws back up. Simple but effective, just like the guitar.

If the main reason for adjusting the neck hight is because of the bridge moving with changes in humidity, would making the bridge or saddle adjustable be an option?

There are a heap of off the shelf bolt capture options available, both fixed and free, so before buying a lathe I think I’d be dropping into Blackwoods and seeing what they have.

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