Filippo Morelli wrote:
Steven,
I just popped over to look at the thread you referenced in the first post. That was helpful. First of off it is clear that you have woodworking chops. So in this regard, while it is your first guitar (and Kent's post is apropos) you are dealing with something that is largely what I like to call a "carpentry issue". It has frankly little to do with sound and mostly to do with structure. To that end, and understanding your knowledge a bit more, let me see if I can provide some additional insights for you to consider in fabricating your neck.
If you are bent set on no truss rod (which is fine ... people here have pointed out the tradeoffs), a simple hardwood insert will work fine - 1/4" wide by 3/8" deep, for example. No taper is necessary. You can use a table saw, a router or be manly about it and bust out your router plane
. Ebony is fine and, in my opinion, any stable hardwood is perfectly fine. As I'm sure you know, gluing in that piece creates a fundamentally different (stiffer, more stable) structure. I keep carbon fiber in the shop for this. But I have also done it with hardwood inserts. Some of the classical guitar weenies I know are using pernambuco, which is to say, at the end of the day most of this is how many fairies are dancing on the head of a pin.
Your insert will serve you well and give you a bit of insurance. I suggest you make the insert somewhat taller than the slot - say 1/16" or so taller. This way, when you go to clamp up, the insert is proud and the clamps ensuring good pressure on the insert against the slot bottom. Any glue will work, but water based glues (AR/PVA/Hide) should be kept clamped for 2 days on the safe side, so the water works its way out. I like polyurethane (PU) glue for this as it is never coming apart (non-reversible glue) and there is no water involved. With PU, I know I said no water, but I like to wipe just a smidge of water on the wood with a slightly damp rag - enough to see the wood color change from transfer. Epoxy works as well. But water based is fine, as long as you clamp for extended time as I mentioned. Once dry, simply plane the insert flat. Make the same glue considerations when gluing the headplate and the fretboard.
Just to add fuel to the fire - I don't believe it has much to do with neck stability over the years, as much as getting some control over the relief that the guitar will have once under tension (since you have no truss rod to control that). You'll want the board flat. As a steel string you may choose to place several thousandths of relief (at greatest depth) between the #5 and #9 frets ON THE BASS side. Expect 0.003" or so relief pulled in under tension. So that gives you 0.005 to 0.007" relief (give or take a few) on the bass side, and maybe half that on the treble side. Alternatively you can put in in the frets after level, though my preference would be to put it on the neck, then dress any additional necessary in the frets after the guitar is strung up for a while.
Others may have a different point of view than what I've stated. This is the kind of stuff that classical builders muck with all the time because we don't generally use truss rods. I hope this helps you Steven. Let us know how it goes. I'll have to remember to pop over and look at your thread.
Filippo
I just popped over to look at the thread you referenced in the first post. That was helpful. First of off it is clear that you have woodworking chops. So in this regard, while it is your first guitar (and Kent's post is apropos) you are dealing with something that is largely what I like to call a "carpentry issue". It has frankly little to do with sound and mostly to do with structure. To that end, and understanding your knowledge a bit more, let me see if I can provide some additional insights for you to consider in fabricating your neck.
If you are bent set on no truss rod (which is fine ... people here have pointed out the tradeoffs), a simple hardwood insert will work fine - 1/4" wide by 3/8" deep, for example. No taper is necessary. You can use a table saw, a router or be manly about it and bust out your router plane
. Ebony is fine and, in my opinion, any stable hardwood is perfectly fine. As I'm sure you know, gluing in that piece creates a fundamentally different (stiffer, more stable) structure. I keep carbon fiber in the shop for this. But I have also done it with hardwood inserts. Some of the classical guitar weenies I know are using pernambuco, which is to say, at the end of the day most of this is how many fairies are dancing on the head of a pin. Your insert will serve you well and give you a bit of insurance. I suggest you make the insert somewhat taller than the slot - say 1/16" or so taller. This way, when you go to clamp up, the insert is proud and the clamps ensuring good pressure on the insert against the slot bottom. Any glue will work, but water based glues (AR/PVA/Hide) should be kept clamped for 2 days on the safe side, so the water works its way out. I like polyurethane (PU) glue for this as it is never coming apart (non-reversible glue) and there is no water involved. With PU, I know I said no water, but I like to wipe just a smidge of water on the wood with a slightly damp rag - enough to see the wood color change from transfer. Epoxy works as well. But water based is fine, as long as you clamp for extended time as I mentioned. Once dry, simply plane the insert flat. Make the same glue considerations when gluing the headplate and the fretboard.
Just to add fuel to the fire - I don't believe it has much to do with neck stability over the years, as much as getting some control over the relief that the guitar will have once under tension (since you have no truss rod to control that). You'll want the board flat. As a steel string you may choose to place several thousandths of relief (at greatest depth) between the #5 and #9 frets ON THE BASS side. Expect 0.003" or so relief pulled in under tension. So that gives you 0.005 to 0.007" relief (give or take a few) on the bass side, and maybe half that on the treble side. Alternatively you can put in in the frets after level, though my preference would be to put it on the neck, then dress any additional necessary in the frets after the guitar is strung up for a while.
Others may have a different point of view than what I've stated. This is the kind of stuff that classical builders muck with all the time because we don't generally use truss rods. I hope this helps you Steven. Let us know how it goes. I'll have to remember to pop over and look at your thread.
Filippo
Thank you, Filippo! For taking your time to make really great comments and suggestions. I really appreciate it! I'll probably go with an ebony insert as you suggested.
, that's way more difficult, and has no real advantage over a double action rod. For nylon strings, it may be a different story, I understand they're sensitive to weight in the neck.