As I’ve been modifying my own templates lately I've become more and more curious about the way the F4 developed from the introduction of the 2 point model around 1912(?) and specifically the adaptations to the narrow neck and the new drastic offset of the fingerboard in the Loar era. I’m also curious about the specific manufacturing procedure they followed (if anyone actually knows). It is clear there was lots of active designing and redesigning of the templates and molds, the glaring example being the shortening of the upper point after 1915 (or is it that the cutaway is less deep?) Of course this is ultimately about the F5, but I think it is important to study its genetics.
To preserve the balance of the scroll, the offsetting of the fingerboard relative to the center of the head block was a problem they were acutely aware of and had a number of ways to solve, with varying degrees of success. I see examples with what appear to be:
A tighter radius below the button/a narrower bell shape of the head block, leaving less meat on the treble/problem side (were there variations in the forms and is there proof of instruments with different shaped head blocks?)
The introduction of a parabolic shaped button rather that the previous ogive that screams CENTER
The steering of the ends of the binding into the button creating the illusion of harmony
The concealing of the misalignment of the center joint and button in the black of the sunburst
The introduction of a one piece neck with no stripe to suggest a true center
And sometimes no adaptation at all and a button that looks like it’s sliding off into the scroll.
A few things stick in my mind in terms of procedures (correct me if I’m wrong, of course): the mortise was established with 3 bandsaw cuts earlier on, and by the Loar era had a dedicated router setup. And the necks were fitted to the rim sans plates, then the back was glued on, and finally the top—this doesn’t mean the neck was glued in first, but that it was set with templates rather than eyeballing an alignment. And lastly the final piece of binding went around the button, which to me implies the neck was glued in after the assembly and full binding of the body.
Having built a lot of instruments and having also worked in a small factory setting I know that process is everything, and trusting a more or less skilled worker in the setting of a neck with a stripe down the middle, a pointed and ridged button and a fingerboard set way off to one side doesn’t seem like a very probable consistent factory solution. And that we love to recycle and adapt jigs and forms that already exist, with "good enough" as an acceptable outcome. I can only imagine that there were two independent operations: a jig to fit the (still somewhat wide) neck more or less on center (with the requisite room for error, cutting, shimming), and then a template with the shape of the fingerboard that indexed into the mold. This shape was drawn on the bare neck, and the neck was worked down to final size. I imagine this was also the procedure in the teens era, but the wider fingerboard made for a much more centered looking neck in most cases. In all of this there is the possibility of screwing up the alignment of the neck in the first place, screwing up the shaping of the neck, screwing up the positioning of the back and its centerline, screwing up the positioning of the top and the f holes relative to the bridge, etc. But in the end it’s all about achieving harmony rather than symmetry.
I would love any input from the resident historians (shoot me down) and also to hear from other builders who have worked through this problem themselves and the adaptations you have made (it looks like everyone crosses this bridge at some point). I have tried both ways, and I see nothing wrong with a redesigning of the head block to allow for a harmonious fretboard position relative to the scroll AND a harmonious button position, working with only one centerline. If you are building Loar copies, I can see the issue.
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