Double Bass Do I need to cut a new bridge for this Kay?

[unbrokenchain]

Would I use maple like the neck or ebony like the fingerboard? Also, doesn't it look funky AF when you reprofile the back of the neck towards the heel to make it uniform thickness? The neck is already crazy thin... Has anyone that has done this operation before have any pictures to help inspire/motivate a guy? I am super curious...

The neck on my Kay has a rosewood shim. Condino did that one, but I did another one a couple years ago with his help, I believe that shim was ebony. No reprofiling was necessary. It's documented here Why hide glue? somewhere later in the thread. I did the carbon fiber reinforcement too (Condino did the routing) and it wasn't bad. To me it's something that all Kays could use, but I also much prefer thick necks.

 

[klyph]

Klyph, can you take another picture of the neck closer the heel?

You bet. The finish job is not the prettiest, but the sound and playability are great...

 

[JBarz]

I'm really considering it, gang. I've got a router that hasn't gotten much action in a while and would love to try to lay in those CF rods... It looks like the taper is so gradual that you don't actually have to reshape the back of the neck then, yeah? My main bass is an American Standard cut down to 42", so I do feel better playing a thick neck... Do you guys much prefer this method for overstand supplementation vs adding material to the bock of the heel block? It seems like I could always just take it off if I wanted to take it back to stock...right?

When this bass was traded in for a SB90, the fingerboard was super ate up with 2mm deep groves in first position, so I had to plane off a lot of material and it's pretty thin but plays perfect. I would want to shape a new thick piece, though, right? - but then, why not just plane the taper into the fingerboard?

Sorry for all the questions. The main reason this is all so exciting for me is because I really don't know much at all about this stuff, so I super appreciate your wisdom, guidance, and patience!

 

[Steven Ayres]

It looks like the taper is so gradual that you don't actually have to reshape the back of the neck then, yeah?

To just increase neck thickness, a flat shim is the thing. To both increase overstand, raise the break angle over the bridge and improve bow clearance, as many prefer on a Kay, the approach is a wedge.

 

[unbrokenchain]

The shim I put on that 69 Kay was flat, it required no manipulation to neck or fingerboard, just a taller bridge. Glued the shim to fingerboard, trimmed down the shim on belt sander, glued to bass, trimmed a little more to flush, and that was it. Getting the fingerboard off in the first place took way longer
My '46 with the Condino neck has a tapered shim, and the break angle is the steepest I've ever seen (which I dig).

edit - you'd also need a taller nut

 

[JBarz]

Oh, ok - I see. So did James reshape the back of the necks profile towards the heel on your '46 to accommodate the taper of the shim, or is a difference in thickness as you go higher in the neck something that you get used to/live with?

 

[JBarz]

I just took a whole bunch of measurements and have come to realize I only need 1/2" shim (no taper!) to match the stance of my #1 bass that I hold to be the gold star standard of excellence. I tried pulling up on the fingerboard to see how difficult it would be to take it off and it's already got a 2" crack where I can get some steam in there, no problem.... I'm not crazy about the idea of a new fingerboard if I can avoid it because this one was a PITA to get right and this is my gut bass anyway, so fingerboard wear will be at a minimum... Dang it, I'm gunna do it, ya'll! Will be ordering CF rods and new nut tonight. I'm excited!

 

[unbrokenchain]

The neck on my '46 is one that Condino made from scratch and grafted on a Kay scroll (so the shim is original to that neck, not a mod). It's extremely thick for a Kay but I love that, can always remove material anyway.

Take your time getting the fingerboard off, it may be easy or it may not. I used a clothes iron on my '69 to assist the process. The board may want to warp in the direction of the heat, but this can be reversed with heat on the other side (once the board is off), or in my case I let it sit with some weights in the middle for a few days. Also be diligent when trimming the shim that you don't take (much) material from the fingerboard, if it gets too narrow you'll have to move it towards the nut and trim the length of the fb, which will give you fewer notes in thumb position. Go slow and you won't have a problem, I can see plainly that your skills are greater than mine

 

[unbrokenchain]

Also, something to know - once the fingerboard is off, that Kay neck will be like a spaghetti noodle, be careful since the scroll weighs quite a bit. It makes things easier to remove the tuning machines (they are heavy), though not totally necessary.

 

[JBarz]

I ordered a piece of 1/2" x 3" x 24" maple from these guys.
Maple by the Piece-1/2" Thickness | Rockler Woodworking and Hardware
I've got a couple of weeks to meditate on things.
Looking at the nut/fingerboard relationship right now, wondering; would you definitely advise against just extending the shim to fit under the nut AND fingerboard - as one piece? Or best to just replace the nut and keep them separate? I'm trying to consider the physics of sound pro/cons with the transfer of the vibration and feel like my head is about to explode...

 

[unbrokenchain]

I ordered a piece of 1/2" x 3" x 24" maple from these guys.
Maple by the Piece-1/2" Thickness | Rockler Woodworking and Hardware
I've got a couple of weeks to meditate on things.
Looking at the nut/fingerboard relationship right now, wondering; would you definitely advise against just extending the shim to fit under the nut AND fingerboard - as one piece? Or best to just replace the nut and keep them separate? I'm trying to consider the physics of sound pro/cons with the transfer of the vibration and feel like my head is about to explode...

You could shim the nut, but it seems much easier to use a separate piece since the fingerboard is narrower than the nut. You could just use a piece of the same maple to shim the existing nut, or nut blanks are not terribly expensive either.
There's any level of complexity to which you can think about musical instruments. For me, I just focus on rigidity and comfort when messing with a neck, leave all the physics equations for the soundpost

 

[klyph]

Hmmm... I know that both your neck AND fb are quite thin, but a straight 1/2" shim seems excessive, and might really change the profile at the nut in an awkward way. It will certainly take a lot of work to blend. Since you are installing CF as well, you won't need the shim to provide stiffness. A tapered shim is actually much less work on the back end and will blend much more easily at the nut. Also, increasing the break angle, even by only a couple of degrees, will do a lot for the sound of the instrument, although I understand you are happy with it now. A shim 1/8" at the nut end and 5/16" at the heel will land the strings in the same place, feel more natural, and increase the break angle. Tapers are very easy to cut on a table saw, and you can practice with scrap dimensional lumber. Food for thought...

EDIT: that taper I specified lands the strings in the same place if it is cut into a blank that is half the mensure, which would then be trimmed to size. Cut into a blank that is already to size would extend the projection further from the body.

 

[klyph]

You might not have enough material thickness in the nut to compensate for a 1/2" shim. You might have to shim it a little, too.

 

[klyph]

Do you see how small the heel of my neck is at the back? When my luthier rebuilt the block and neck joint, he corrected the break angle. That is why he could get away with a 1/8" straight shim- which still radically alters the feel of the neck. Compare that with the pic of your bass. Again... just food for thought.

 

[JBarz]

I feel good about this 1/2" shim because it will make this Kay feel exactly like my thick American Standard neck. It'll also put the overstand exactly in the same place as the AmStd. The only problem is the fingerboard is about 1/4" wider on the Standard, with a more dramatic taper out, but I'd rather not have to plane another fresh ebony fingerboard and that'd throw off all this synchronistic 1/2" geometry I'm tripping out on, anyway - I'll live with the narrow, thick neck, methinks. Furthermore, my favorite part is if I don't like it or can't make the nut jive, I can always undo it and try a wedge or go back stock, etc.

 

[JBarz]

It looks like 1/4" shim and a new 5/8" fingerboard would get me to the same place. This probably makes more sense in the long run - if I'm going to do this much work already, I might as well throw a new slab of ebony on there and be able to shape it to my liking. Whew! I'm getting nervous about the idea of routing the carbon fiber slots - any tips and tricks would be appreciated.

 

[unbrokenchain]

It looks like 1/4" shim and a new 5/8" fingerboard would get me to the same place. This probably makes more sense in the long run - if I'm going to do this much work already, I might as well throw a new slab of ebony on there and be able to shape it to my liking. Whew! I'm getting nervous about the idea of routing the carbon fiber slots - any tips and tricks would be appreciated.

Just watch your depth on the thinnest part of the neck, I didn't need to say that , make yourself a jig.

Shaping a new fingerboard though, whew.. that's something that's very much an art form. I mean all luthiery is, but FB planing is the one thing I won't do myself (again) . It's maybe the most important factor in playability of the instrument. You will be worth your weight in gold to other players if you get comfortable with that skill, so I personally think you should, but if it's at all possible to work with/under a pro for that part, I would highly recommend it!

edit - posting on the from my work iPad is so frustrating, autocorrect turns me into a goober every sentence

 

[JBarz]

Your confidence in me is inspiring and flattering, even if undeserved, lol — I'm just figuring this stuff out. BTW, I much prefer the "fix-and-flip" instrument repair business model as opposed to working on customers horns (basses) directly. Doing stuff for $$$ always sours me on a thing, but I think I'd gladly tinker on anyone's axe (restore edges or whatever) in exchange for more broken basses & parts that need some TLC - PM me if interested.

The really neat thing about this project is that, by the blessings of my esteemed bass sensai Scott, I have this AmStd bass that was setup to perfection will all the funky magic juju by the Cincinnati Bass Cellar guys to play and, more pertinently, copy the setup on.... That leaves the S9 to be "in the shop" as long as I need something to keep me busy tinkering. I remember the one neck I planed wasn't super difficult, just time consuming. I think it took a solid 25+ hrs. But hell, if it keeps me off stupid Facebook and not staring at the ding dang screens - it's totally worth the $200 for a new fingerboard blank cost of admission. Ya'll make me happy. Thanks for giving me a place to foster and cultivate my obsession.

 

[klyph]

It looks like 1/4" shim and a new 5/8" fingerboard would get me to the same place. This probably makes more sense in the long run - if I'm going to do this much work already, I might as well throw a new slab of ebony on there and be able to shape it to my liking. Whew! I'm getting nervous about the idea of routing the carbon fiber slots - any tips and tricks would be appreciated.

NOW yer talkin!
A thick piece of ebony makes a huge difference (as does properly planed hard maple). Remember, this mod existed for many decades before the invention of cf. Also, you could just put the cf in the shim if you like, to alleviate worries about messing up the neck. Either way, that joint has to be pristine, and the wood as stable as possible (but you knew that;-) )

 

[JBarz]

Being able to put the CF rods in the 1/4" shim instead of the neck is a game changer, for sure! It will be infinitely easier to route out a perfectly straight line off the edge of the uncut shim. Thank you thank you!