6K TOW Carbin fiber thread... genius!

[Prostheta]

My first 5-string was a Maple neck and stable as well. No reinforcement. Sometimes a neck is good, sometimes not. Laminations do help stack the odds in your favour of course  Opposing grain has never seemed to make much difference to me beyond cosmetics. It's enough to maintain symmetry and aim for vertical growth ring alignment. I don't think quartersawn, or similar alignment makes a neck stiffer....just more geometrically stable as the wood moves around tangentially/radially.

I rarely get chance to select truly good wood on my budget or immediate availability, so a straight Maple-only neck could be a crapshoot for me as it's rarely ultra-perfect. If I reproduced my RBX-775's neck, I don't know if it would be as stable or stiff as the original unless I really spunked cash on an overpriced blank from a recognised source....even then....

Purpleheart is plenty stiff as it stands. Beyond a basic layup of ripped and flipped Maple, these should be more than enough. CF would be a bonus. Whilst I prefer compression rods these days, they do make a neck move around. Toneful beggars, but needy as well!

[Bizman62]

Well... some logical pondering here again without any real experience:

A laminated neck is more rigid than a single piece neck, right? And why is that? Obviously there's something else than wood involved. The glue between the veneers/slats is a solid uniform mass unlike wood. Now aren't square carbon fibre rods just that, solid uniform mass unlike wood? If ultra thin layers of glue can make wood stiffer, carbon fibre sticks can make it even stiffer. Will it be too stiff is about proportions. If a multi-lam neck is almost stiff enough, the thinnest carbon fibre slabs you can get are most likely enough. If not, keep adding them until you've reached your goal.

[mistermikev]

1 hour ago, Prostheta said:

My first 5-string was a Maple neck and stable as well. No reinforcement. Sometimes a neck is good, sometimes not. Laminations do help stack the odds in your favour of course  Opposing grain has never seemed to make much difference to me beyond cosmetics. It's enough to maintain symmetry and aim for vertical growth ring alignment. I don't think quartersawn, or similar alignment makes a neck stiffer....just more geometrically stable as the wood moves around tangentially/radially.

I rarely get chance to select truly good wood on my budget or immediate availability, so a straight Maple-only neck could be a crapshoot for me as it's rarely ultra-perfect. If I reproduced my RBX-775's neck, I don't know if it would be as stable or stiff as the original unless I really spunked cash on an overpriced blank from a recognised source....even then....

Purpleheart is plenty stiff as it stands. Beyond a basic layup of ripped and flipped Maple, these should be more than enough. CF would be a bonus. Whilst I prefer compression rods these days, they do make a neck move around. Toneful beggars, but needy as well!

right-o.  I think if I did this neck using a single piece of the birdseye I have access too - we'd be golden... but that's not the right wood for this build.  I believe you are right about the multilam being enough... but there is one variable I left out that might make it more uncertain - 35" scale.  I'm also using an allied truss which I think probably does add some stability as they are well made and fairly rigid.  all that said... If the price of knowing you've done everything you can do is a little extra effort and a few carbon fiber rods... I'm in.  Will be something I can check off my "haven't done yet" list too so... think that's the way to go!

[Prostheta]

My RBX is a 35" scale as are all my 5-ers other than the SB. It doesn't make that much of a difference, however I don't play heavy gauge strings. Just "normal".

Laminated necks are only slightly stiffer from their laminated nature, however it's common to laminate in stiffer woods for that goal. Bubinga and Wengé are two favourites I like to go back to, whether between Maple or Mahogany-ish woods. I choose my words carefully when discussing neck construction as stability and stiffness are two different things. "Stable" can often be confused or used interchangeably with "stiff", but generally it means the wood doesn't distort its cross-sectional shape excessively when taking in or giving back moisture to the environment. This is why I mentioned growth ring alignment....tighter radii in growth rings leads to all manner of screwy things happening, especially from tangential movement. Stiffness should purely be regarded as the resistance to bending under string tension.

A couple of carbon fibre rods are nice insurance, let's put it that way. They're not intrusive to the sound of the neck (some might spend ages arguing this, I prefer to practice, play and enjoy instead) and I think the task of slotting for rods is a good basic technical exercise, especially if in line with the taper. When not using compression rods, I really like the U-channel Gotoh rods. They're not the easiest to acquire sometimes, but they've always produced fine necks. Importing from Allied is a ballache.

You could always laminate in some CF pinstripes. Staple it on the endgrain both ends and stretch it over the laminate. If not that contributive, it's a fun thing to have in there.

[mistermikev]

40 minutes ago, Prostheta said:

My RBX is a 35" scale as are all my 5-ers other than the SB. It doesn't make that much of a difference, however I don't play heavy gauge strings. Just "normal".

Laminated necks are only slightly stiffer from their laminated nature, however it's common to laminate in stiffer woods for that goal. Bubinga and Wengé are two favourites I like to go back to, whether between Maple or Mahogany-ish woods. I choose my words carefully when discussing neck construction as stability and stiffness are two different things. "Stable" can often be confused or used interchangeably with "stiff", but generally it means the wood doesn't distort its cross-sectional shape excessively when taking in or giving back moisture to the environment. This is why I mentioned growth ring alignment....tighter radii in growth rings leads to all manner of screwy things happening, especially from tangential movement. Stiffness should purely be regarded as the resistance to bending under string tension.

A couple of carbon fibre rods are nice insurance, let's put it that way. They're not intrusive to the sound of the neck (some might spend ages arguing this, I prefer to practice, play and enjoy instead) and I think the task of slotting for rods is a good basic technical exercise, especially if in line with the taper. When not using compression rods, I really like the U-channel Gotoh rods. They're not the easiest to acquire sometimes, but they've always produced fine necks. Importing from Allied is a ballache.

You could always laminate in some CF pinstripes. Staple it on the endgrain both ends and stretch it over the laminate. If not that contributive, it's a fun thing to have in there.

always learn a thing or two when I chat w you - thanks for that.  I love wenge and have observed/used it's rigid properties at least two times now.  was not aware that bubinga was rigid.  I always loved the look of it... but passed it up at the local spot because I thought it was about the sm as mahogany.  I may have to snag some next time I'm there.  I imagine sapelle is on that list too.  have some of that and haven't cut any but I'm told it's hard on the tools.

the dif between stiff and stable is def not lost on me.  I am aware that mahog is very stable but it's not what I'd call stiff.  in fact, maple is perhaps more stiff but depending on the piece can be less stable. 

learned some new uk slang too... ballache! 

i like where you were going with the cf pinstripes.  I was thinking... if one cut some grooves on the back side of a shaped neck... then wrap carbon fiber thread around screws at both ends... turn the screw to tighten... then pour in epoxy.  Might add some stiffness.  Might look kind of cool.  Something to try when I'm feeling 'sperimental!

now that makes me think... what about carbon fiber binding?  wouldn't want to have to bend it around anything, but on the sides of the fretboard that could be pretty cool.  That said... it might fight the truss rod too effectively. 

just spitballing here. 

 

[mistermikev]

total divergence... but I meant to ask: do you perhaps use a tablesaw jig to put a taper in laminates for a bass neck?  if so... any chance you have a pic?  I've seen a few jigs that I'm not fully satisfied with and learning towards typical mitre jig with toggle clamps.  Just wondering what others use?

[Bizman62]

11 hours ago, Prostheta said:

I choose my words carefully when discussing neck construction as stability and stiffness are two different things. "Stable" can often be confused or used interchangeably with "stiff", but generally it means the wood doesn't distort its cross-sectional shape excessively when taking in or giving back moisture to the environment. This is why I mentioned growth ring alignment.

That's a very good point, something that especially we non-native English speakers easily can mix.

Stiff may indeed want to stabilize into unwanted shapes!

[Prostheta]

I don't know if it is entirely a matter of language, but certainly "stability" means different things to some people. Being specific about meaning makes all the difference. Very true about stiff woods wanting to stabilise. Cut a board from a tree that has lyly, or compression grain from growing on an incline and it'll stabilise into a pretzel however stiff it is!

[Bizman62]

Lyly indeed! Gotta love how you drop Finnish terms amidst perfect English. That's hilarious!

 

[Prostheta]

Well the truth of it is that I learned a lot of the more technical aspects of wood processing and manufacture in Finnish! Before my two degrees I wasn't that knowledgeable about tree anatomy/lifecycle, forestry management, sawmill processing and general lumber production, grading, drying, etc. I filled in my English terms across as I learnt it in Finnish. I'm not even sure if there's an English term for reaktiopuu....gravitropic growth maybe? It's easy to see off the log as you'll generally have a way off-centre pith and the growth rings can be read as having compression/tension.

[Bizman62]

Often when I'm not sure about the exact term in English I search for the Finnish Wikipedia and see if there's an English article about the subject. Like Reaktiopuu->https://en.wikipedia.org/wiki/Reaction_wood

[Prostheta]

So there is....! Well, that's in line with my understanding of things. You can read the likelihood of reaction wood as I described; the differentiation between growth rings being distorted illustrates the issues of less than ideal lignin or cellulose ratios on the compression and tension sides. I get a lot of this in Sapele since that rarely grows straight. Sawing that often releases internal tensions that feel like when sea ice booms as it cracks. Really deep sounds coming from within the material. When sawing wood that sounds like creaking boards on a pirate ship, yeah, watch out.

<edit: cool - that Wikipedia article mentions gravitropism as well! thanks>