• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Double Bass Neck heel crack, fingerboard modification, no budget...

Silverface

Silverface

Jun 4, 2008
81
28
Hermosa Beach CA
#1
Yeah, I can see repair persons hoping for a good laugh - or just running for the hills!:woot:

This a is a continuation of a "string tension" thread I started about 8 months ago. Briefly, I bought a damaged Upton Hawkes to help a friend, repaired it, and installed low-tension strings because of 1) a repaired neck heel crack and 2) arthritis in my left thumb joint combined with the (IMO) ridiculously awful Romburg Bevel.

The fingerboard had broken and splintered and there was a clean neck heel crack - I repaired both and everything was working fine with low-tension kevlar/nylon strings. I don’t need much volume - it’s just me and “play along” tracks.

The story continues thusly - a friend knocked it on its face (the cause of the pre-purchase damage), opening the heel crack and splintering the fingerboard - again!

Caveats:

1. I'm a crappy upright player. I used to gig with a country/rock/swing band but now just play it only for fun and only at home. I mainly play 6-string guitars and other instruments.

2. I’m permanently disabled by chronic pain & other “stuff” that stopped my gigging. I'm on a fixed income with no funds for "real" repairs - and I'm stuck at home except for doc appointments. It'd be very tough for me to have it transported anywhere.

3. I’ve done instrument and amp tech work on the side since the 1970's, including finish work, headstock repairs, crack & brace work, soundpost setting, bridge shaping/fitting etc. (enough string instrument work to *not* do stupid, irreversible “non-repairs” on good instruments).

I managed to fix the fingerboard *again*, plus remove most of the hated Romburg Bevel (while maintaining decent neck relief.) I’d like to replace it with a new one but can’t find anything I can afford in its odd dimensions (1 3/8w x 1/2”h at the nut; 33 1/2 L x 3 1/2” w at the end - the width and height at the nut being the problems).

I flat can’t afford a pro-quality fingerboard or a "parts & labor" job - nor can I transport it anywhere. I'm limited to my tech skills/equipment.

The real issue is the heel crack. The second “accident” opened it quite a bit more than the first time. I know from experience that a “glue and clamp” job won’t hold, even with the cheap “noodle” strings I’m using.

OTOH I can’t afford a neck replacement, and installing a new neck myself is FAR more work than I am willing to undertake. It’s not worth the $$ to me anyway for the amount of use it gets. But I don’t want to sell it to someone that wants to do "correct" repairs & replace it with a cheap bass either. I have some history with this one (other than the repair “fun”.)

All that to get to two questions!

1. Does anyone know of a source for a “budget” ebony fingerboard (<$250) that’s the correct size, has no Romburg Bevel and has proper relief (many don’t)? Even a used one would be fine. This is the repaired 'board the first time - looks similar now except the bevel is nearly nonexistent. Not "pretty" but smooth and playable. I just wanted readers to know what the repair(s) look like (Pretty amazing what can be done with hot hide glue, thin superglue and ebony dust!).
repaired fingerboard.JPG

2. I only see one “for sure” heel crack repair/reinforcement method, which would involve opening the back seam for access, drilling a small-diameter hole from the heel to the front of the neck (with fingerboard removed), and installing a long bolt with washers and nut “internally clamp” it like in the drawing below (credit to lutherie.net). The photo is my actual bass.

heel crack & back sep.jpg
bass.heel.repair.gif


I’d open the back seam for access because I’d prefer not drilling a visible hole through the back. A second thought is using a razor saw to cut precisely at the bottom of the back’s heel “cap” and removing only that piece, which would be glued back in place and the cut line very unobtrusive.

With the bolt as the primary “attachment” the glue is less critical - I usually use hot hide glue but in a case like this epoxy might be acceptable, since it’s not the type of work that needs to be reversible.

Opinions? Alternative ideas? Fingerboard sources?

Again, please take into account my very limited finances, lack of transportation and non-critical use of the instrument itself.

Thanks much! Sorry for the length but there was a lot to cover!
 
#5
There are many ways to approach fixing a heel break, and there's essentially one that will work well long-term: pull the neck, clean and repair the heel break with proper adhesive, clean and dress the top-block joint so the neck fits again (the stress of the fracture will have damaged it), and put it back together with proper adhesive. There are style variations in there, but that's the thing in a nutshell.

Putting a bolt through the heel seems like a simple way to approach it, and believe me many have tried that. The thing is, in terms of the real strength necessary to secure the neck in position, the bolt can't do it — it's not precise enough to maintain a good joint with the kind of stress the heel carries. On the other hand, a good, solid glue joint in the heel and a good, solid glue joint in the block become a system that's not only cleaner and reversible, it's stronger.
 
  • Like
Reactions: RSBBass, SAlcott and Tom Lane
#6
I understand those forces Steven - but as noted we've determined that it's not a break,\ it's a construction joint that cuts through the grain and is visually parallel with the top plane. I've 'scoped the interior and there's no sign of a break or shift at the neck block. The stress it will carry is apparently the same as it did originally.

Respectfully, I don't think you paid attention to my situation and only looked at the technical issues. Neck removal and a reset can't/won't be done, unless you know a local bass tech that makes house calls - for free. (note - I'm trying to add a little humor here!):roflmao:

If you don't think the bolt system is the best way to secure this construction joint, fine - I appreciate your position. But suggesting neck block work goes outside the limits I clearly mentioned and doesn't help get the bass playable.
 
#7
You are now into the "necessary evil" repairs area. The neck is clearly AFU and this is the second go around. I'd rather use something like a self tightening torx lag or spax bolt rather than a threaded rod with nuts that can come lose inside and rattle from within. I think you have the basic idea correct. Even if you don't keep the hardware in there permanently, it makes for fantastic alignment tools when gluing everything in place.

This is a perfect example of why many of us always suggest hot hide glue and never epoxy. You already did a similar repair once and now it has happened again. Your prior use of hot hide glue means that it will all come apart easily and you can get to work on the new issues. If you had followed the advice of some, essentially: " Aw, F@#$ IT, just fill it with epoxy and call it good...", then you would have a useless nightmare of gloop held together with no second chances.

Remember that there is often a point where if you cannot afford to do it correct, then the world is sending you a message not to mess with it right now. Often you can do it quick, you can do it easy, you can do it cheap, but to do it well rarely will all of those 3 things line up together, just like the second most asked questions around here: "How do I setup my bass so the action is incredibly low, super fast and easy on my hands, and has a lot of volume....

Do it well. Do it with a well thought out reason and intent. Do it with materials that are reversible, so when the inevitable, "@#$%&!" moment happens, you can do it all over again.

Good luck with your project.
 
  • Like
Reactions: AGCurry, Phil Rowan and misterbadger
#9
The neck heel crack looks strange, very straight, as if someone had taken a thin kerf hand saw and sawed it through.

I would tend to favor slanting the bolt to be more perpendicular to the fingerboard rather than parallel to the ribs. I'm thinking that the force/stress on the neck is mostly like a lever, with the fulcrum being in the corner of the top and ribs in the neck block. With the neck stressed like that, the stress on the bolt where the crack is would be more shearing than tension. If you slant it more it would it would reduce a bit the shear stress in favor of tension. Just my opinion.

Anyway, Gollihur has an ebony fingerboard for $205 plus shipping:

Invalid Link Removed

You'll need to shape it into your dimensions, but I would think that's a given with any spare fingerboard you may buy.

Also, with the promotion by the gentleman from Taylor guitars to use ebony that is not naturally black, you might be able to find something more reasonable in that grade. For example LMII, a vendor for guitar woods and parts, has these fingerboards for guitar or bass guitars. If you talk to them they might be able to point where you could get wood in the dimension needed for an upright fingerboard:

Ebony Fingerboards, West African
 
#10
OK, third time through this -

We've already determined it's NOT a crack. It's a joint, and the way the neck was originally built. I have not seen a joint in this kind of area except on newer guitars with necks made of multiple "slices" and laminated under high heat and pressure. This is a simple butt joint, which doesn't make much sense to me. But it is what it is, and IMO it *needs* reinforcement. It was already repaired with HHG once, and while it held it could only take very low-tension strings as mentioned. I tried a different string set when originally re-glued and it started to open up, requiring a re-do of the glue job.

As far as "doing it right" - yeah, great idea. But I do not have the financial OR transportation resources to do that. I thought I made that very clear. So I'd appreciate help that focuses on getting the best possible results in the context I laid out. "Wait and do it the right way" doesn't help, because it can't happen.
 
#12
I have never repaired one of these, but I would have a concern about the steel bolt as follows.

When you tighten down that bolt, it's going to be many orders of magnitude stiffer and harder than the wood it's compressing. Now when the wood expands and contracts with temperature and humidity, I would be concerned that the bolt won't be doing so, thus it will be crushing down the wood fibers under the bolt head and nut - the bolt thus getting progressively looser as the months/years go by.

I don't know whether that's a real concern or not, but it's the first thing I thought of. I would either leave a facility to re-tighten the bolt very easily, and/or put a bunch of hide glue down in the "crack" and use the bolt primarily as a clamping device. (Yes, I know it's a separated joint rather than a crack through parent material.)

One could also use stacked Belleville washers to maintain a compression force while also allowing for some swelling and shrinking of the wood. You'd have to do some basic calculations of the required forces, and you'd probably want to use a couple of nuts jammed together to set the compression force of the Bellevilles.

The bigger area of wood you spread the force of the bolt/nut over, the better off you'll be.

Another question: what's happening at the neck tenon-to-neck block joint? If there is a visible separation between the two parts of the neck heel, that implies to me that one of those parts (probably the part closest to the finger board) has moved in the neck-tenon-to-neck block joint. Once the glue joint there is lost, it seems like there's little hope, as you'll now be using half of that joint plus the button joint to hold the neck.

OP, if you have enough skill to carry out the bolt-reinforced repair as you've described, you may have enough skill to slowly work your way through a neck removal/heel joint repair/neck refit.

Again, I am not a double bass luthier, nor even an imitation one, but I am a mechanical engineer with 35 years of experience, a great deal of it related to threaded fasteners, and I have a lot of experience at bolting wood in residential construction as well.
 
Last edited:
#13
Keep in mind that the button ("neck heel cap" as you referred to it in your earlier post) has a significant structural function. Cutting through it with a razor saw may trigger unintended consequences.

You might want to consider the economics of this situation. The bass (assuming it's ply - hybrid was a little more expensive) was about $1700 new, now around $1000-$1200 in good used (meaning no neck repair) condition. You're facing a lot of work fitting a new fingerboard, which is why luthiers around here charge around $1000 for a replacement. I'm not clear that you have the tools or experience to properly shape a fingerboard - this is not a "plug and play" situation.

I'm surprised that the Romberg bevel (my Upton Hawkes didn't have one FWIW) is an issue for you. I prefer a rounded profile, but have owned both and can't say that the bevel was an issue in any way.

My advice? Either get friends who aren't so clumsy or store the bass where it can't fall on its face. Hot hide glue the thing the best you can, put on the lightest tension strings you can find, and live with it. Oh, and wear serious dust protection when working with ebony. Nasty stuff.
 
Last edited:
#14
KUNGfuSHERIFF said:
That might not be a crack at all...I'd expect it crack with the grain and not across it. Lots of budget basses have stacked heels. Yours might too. Your thinking on hardware for a permanent repair seems sound.

Call Metropolitan Music for a fingerboard. IIRC they charge about $250 for a midgrade ebony board.
Click to expand...
KFS - this question is because I don't know as much as I'd like to know about bass construction: How could the pictured neck heel with crack be a "stacked" construction when the photo clearly shows the crack crossing the grain?

When I think of "stacked" construction, I think of knives where the handle material is leather washers, stacked and varnished to hold them together. You can clearly see that the washers are parallel. Is that different from using the technique on the heel of a bass neck?
 
#15
BobKay said:
KFS - this question is because I don't know as much as I'd like to know about bass construction: How could the pictured neck heel with crack be a "stacked" construction when the photo clearly shows the crack crossing the grain?
Click to expand...

Look closer. The grain lines on one side of the joint have nothing to do with the grain lines on the other.

For all I know the two sections were cut from different trees.
 
#16
Cheap ebony fingerboards are a complete waste of $$$$$$$$! The main cost with a fingerboard replacement is labor. Why go to all of that trouble so you can save $75 in materials and wind up with some improperly seasoned, off quarter or flatsawn cheap Chinese crap that will warp like a potato chip within a few months leaving the fingerboard in worse condition........Get a proper one from International Violin for a few dollars more and you'll have a lifetime of stable service.
 
  • Like
Reactions: keiranhohara and misterbadger
#17
On the fingerboard, would it be practical to insert a thin shim of maple between the FB and neck as part of this repair, thus giving a little more meat for dressing/shaping/etc.? Seems like that would be less costly than a whole new FB.
 

Latest posts

Top Bottom
Back