Neck Construction and width

[trekster]

In looking over some of the many manufacturers of thru-neck basses, I've noticed that there are several styles of manufacturing.  One of the more prominent differences is the width of the neck laminates where the body leaves(sp?) attach.  For instance, Alembic seems to make their neck lams just about the width of the end of the fingerboard.  Others make them a lot wider (think Gibson Thunderbird basses and Firebird guitars), or add further laminates between the body leaves and the neck (which actually gives that sorta cool sports-stripe effect).
 
What I was wondering was if Alembic has a particular, scientific, asthetic or that's the way, uh-huh, uh-huh we do it uh-huh, uh-huh reason for thier choice of construction.  
 
Of course, if anyone has any opinions, by all means fire away.
 
--T

[sfnic]

Well, I'm not sure if it was part of the original reasoning, but one of the advantages of the Alembic design for _me_ is that I can get useful neck wood from slab-sawn maple 4/4 stock.  The outside lams being a real-world 3/4 wide means I can mill comfortable with little spoilage and end up with quarter-sawn lams.  In general, I can get two necks (2 1/4 wide blanks) out of a single 4/4 x 12 x 48 board of rock maple. (Plus the ebony, purpleheart, or walnut lams, of course.)
 
With wider outer lams, I'd end up spending a lot more for either 8/4 stock or quarter-sawn lumber.  So for me it's a cost/materials issue, especially if I'm using more expensive hardwoods for the outer lams (purpleheart or wenge, for instance, with two maple interior stripes).  Believe me, you don't want to know the cost per board foot of 4/4 quarter-sawn wenge...

[bigredbass]

I worked in the production line at Gibson when I first moved to Nashville in the early 90s.  Of course, Gibson has never been a big presence in bass over the years, nor were they at that time.  So when a TBird would come through, I studied them, having always been a fan of neck thru instruments.  As I look back, several things stood out:
 
If you've ever held a clear finish TBird, center section is almost all mahogany with only thin layers for the lams, almost a pin stripe layer.  I'm guessing they make up the stiffness with the ebony fingerboard, although mahogany is generally not an awfully temperamental wood.  Gibson did go to the trouble of drying the wood for a year after they received their lumber in their rough sizes.
 
Viewed from the butt end, another thing struck me.  Instead of the wing to lamination joint simply being a flat joint, the sides of the lam had a V-slot and the wings had a matching V-point
as the glue joint.
 
Also, on TBirds, the lam is much wider than the neck width.  The 'step' you feel above and below the strings on the body is the joint.  I wrote this off to some 50s styling ethic until it dawned on me it had to be that wide to allow them to include that massive Fenderish headstock.
 
My two Yamaha BB5000s are fairly straight forward with a twist:  3ply rock maple, with 2 mahogany strips between, Alder wings, and unstained Macassar ebony fingerboard so you see the 'fudge' stripes in the ebony.  But . . . the two outer maple plies are wider and there's a another mahogany lam where the wings add on . . .
but they don't show up on the edges of the headstock, which have the two centers but are maple the rest of the way to the edges.  Hmmmmm . . . . .
 
I'm sure it's done all kinds of ways, but those are two I've seen up close, besides my SPOILER 5.
 
J o e y

[son_of_magni]

Two things come to mind thinking about my building experiences.  First, if the neck blank is made wide enough there is no need to add headstock wings, which means one less step to perform.  And second I am more comfortable, for some reason, rasping out the neck-to-body transition if the neck stock is a good bit wider than the fingerboard.
 
But when making a large body bass and using these heavy hardwoods it makes a lot of sense from a weight perspective to make the neck blank as narrow as possible.  So my guess would be that Alembic does it the hard way mostly for ergonomic reasons.
 
(Message edited by son_of_magni on May 08, 2005)

[sfnic]

Another thing Alembic does, courtesy of the relatively narrow neck construction, is bury the scarf joint for the headstock.  First, they scarf the headstock with about a 14 degree (IIRC) back angle.  Then they glue on the wings to bring the headstock out to the proper width.  That hides the sides of the scarf joint.  Then they add the front and rear laminations, which hide the front and back faces of the joint.
 
Makes it much cleaner looking and, especially with the front and rear laminations, MUCH stronger than an exposed scarf joint would be.  
 
They could add even more structural support for the joine by adding an ebony (or graphite) spline joint (or steel pins, for that matter) to attach the headstock wings, but that's probably overkill and would add a touch of extra weight on what's already a slightly head-heavy instrument.

[bob]

Interesting... I knew about the little wings (pretty obvious), but hadn't really thought about them hiding a scarf joint, figured it was just to add width.
 
Though of course it would be a huge waste of wood to get that angle without the scarf, so I went poking around in FTC, and finally found one that makes it fairly clear (two, actually).

[David Houck]

I found this pretty interesting too!  Here is a page showing the construction of a non-Alembic guitar with a pretty good picture of a scarf joint.  Looking at my Orion, I don't think the stock set neck basses have scarf joints (there are of course no rear laminations).  If the Orion does, I sure can't see it.

[bob]

That occurred to me a short while later - necks with the volute use a continuous piece of wood. At one point I thought it might be cool to leave the ebony neck lams exposed on the back of the headstock, and without the back laminate they would have added a volute. I'm pretty sure in this case there would not have been a joint.
 
So why? Is it to save wood, when they have the option to cover it? And how does that trade off against the labor? Or is it perhaps even stronger to put more of the grain in line with the peghead? Doesn't seem like that would be likely, and pretty clearly not necessary.

[David Houck]

What I don't understand (maybe this is what you are asking) is why, if the headstock on an Orion is a continuous piece of wood, why the headstock on a through neck can't also be a continuous piece of wood.  It seems to me that the continuous wood would be stronger than the scarf joint, especially if you are putting multiple front and back laminates on it.  The thickness of a set neck at the body, since it sits in the body, is less think than on a neck through; thus there would be even more of a waste of wood.
 
I too think a neck through with a volute instead of back laminates would look nice.

[sfnic]

You can do a volute on a scarf-jointed neck fairly easily.  Instead of starting with a 3/4 thick headstock, take it up to 5/4 thick.  Then bandsaw the backside to shape the volute, as you would a single-piece, non-jointed neck. It only adds a bit of strength, of course, but it's really more of a brace to keep the headstock wood from splitting.  
 
(In rare cases, the headstock wood fails before the glue joint does; adding a faux volute helps eliminate that possibility.  It doesn't help the glue joint, though...)
 
The Orion may well have a scarf joint.  The necks I saw at the factory were VERY cleanly done; it was extremely difficult to see the scarf from either the front or rear.  On one of them, the joint line was damned near invisible, and they had matched the grain AND curl patterns to hide it.  Under finish, it'd have been impossible to see.
 
Another reason for using the scarf joint method on the neck-throughs is that it's common to use 48 long stock.  A standard point bass is, IIRC, about 48/5 long, from tip to tip.  During construction, it's an inch or three longer, as the neck blank is cut extra long to allow for jigging (having that extra protrusion at the foot makes a great clamping point) and later for shaping the point.  So using a hunk of the falloff (from the neck undercut) to extend the blank via the scarffed headstock means not having to go to non-standard maple stock.

[David Houck]

it's common to use 48 long stock.
 
Aha!!  Ok, that makes sense.  Thanks!

[mica]

The scarf joint also breaks in a very predicable and easy to repair fashion. It's one of the reasons the technique has been popularized and used for hundresd of years. Considering the angle of the peghead and the body, without a scarf joint, a great deal of material would wind up in the scrap pile. And as Nick points out, material is readily available in 48 lengths, though we do mill custom lengths for many jobs.  
 
No scarf joint on the set necks - the hefty volute does the reinforcing there. Unless it's a set neck without a volute, then there's a scarf joint hidden inside the ears. Only a few of the volute-style pegheads have come back for repair. These tend to break along one of the outer joints, and again, it's pretty easy to repair. There was one bass that went through a car accident. That poor Epic 5 sacrificed its head and the driver was totally safe.  
 
On to the original post - the precise dimensions aren't important, what is important is the glue joints. By using 4 or more joints, we can engineer a beam that is stronger and more predictable than an unlaminated beam. It's also lovely looking.  
 
We've always made the neck through the body portion of the neck the same width as the end of the fingerboard. Thinking back to the original Series I and II (even before they had those designations), the thought was to make the body lighter weight and hollow - so having a wide neck at the center would have greatly increased the weight.  
 
On some instruments, we add the racing stripes you refer to. My Essence (with new strings now Rory!) has Purpleheart veneers framing the neck. It's really cool, since the top is Kingwood, you can't see them except from the back.

[sfnic]

Well, let me clarify that statement a bit...
 
It's common if you're a cheap-assed builder like me, who's trying to save money on foundation wood (maple for the necks, mahogany for the cores) in order to be able to afford better hardware and electronics, and some really nice top/back woods.
 
This is not to say that I'm buying crap maple; it's very good stock, but in off-the-shelf sizes.  So I adapt my designs slightly to make use of what I can get easily.  
 
Now, the spalted maple billets I got for two projects (probably a matched set of fretted/fretless basses), and the double-cathedral-figured wenge for another, were definitely not off-the-shelf.
 
If only free time were as cheap as the wood...

[David Houck]

Thanks Mica!!  I certainly know a lot more about headstock construction than I did when I woke up this morning!

[trekster]

Indeed, thanks Mica and the rest of you,  My curiosity has been satiated.
 
Now for my reasoning -- I *finally* got my workshop cleaned out (after 3 years), and realized I have several projects in progress but no completion.  First to get done -- my 8-string.  However, when I bought my bubinga for the body parts (front and back sandwiching a mahogany core, maple veneer, and 1/8 purpleheart sheet), I didn't buy it wide enough to make a non-Spector sized body.  So, I was wondering (but not anymore!) if framing the neck-thru at the body with matching 1/4 bubinga and maple veneer for racing stripes would be a detriment to the sound or quality of my finished project.
 
--T