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Double Bass Replacement neck fitting

eh_train

eh_train

Supporting Member
Commercial User
Jan 12, 2004
1,493
1,270
Toronto
www.standupguybasses.com
Disclosures
Owner, Stand Up Guy Basses (Repair/Sell/Buy upright basses)
#1
Hi all,

I posted earlier about putting a German shop bass back into commission. It had a broken off stump for a neck. The neck body/join was very solid, but the upper one third of the neck, and the scroll, were missing. After some back and forth with TBers about whether to graft something on or start over, I decided on a whole new neck.

The good news is that I got the old neck out pretty cleanly. I also have a new-found appreciation for how secure a well-set neck is!

The less good news is that I bought a replacement neck which may be difficult to fit. The biggest problem is the angle of the neck as compared to the old one. The old neck angle seemed ideal, so I'd like to replicate it if possible. By this I mean the original overstand was 1.25", and I estimated the bridge height to be 6.5".

If you check pic #1, with the old and new necks sitting flat on a table, the old neck angle was something like 83 degrees, while the new one is more like 75 degrees. With this new slope, if I used the same overstand, the bridge height would be 9" or more! Reducing the overstand is probably a bad idea.

The obvious solution is to take a wedge shaped slice off the front of the foot, however that would reduce the width of the neck (i.e., the width of the fingerboard). There isn't any wiggle room for reducing the new neck width, as it's already 1/16" narrower than the original.

SO, I am wondering about changing the neck angle by adding a wedge to the foot of the new neck, at the back. You can see what I mean in pic #2 (I have "corrected" the angle to match that of the old neck by "shimming" - actually my son's 1/2" thick pencil sharpener. I could use wood from the old neck for this purpose. Note, the addition of a wedge would be invisible once the neck is reset.

I realize the best solution is to have enough pre-existing wood at the foot. I think this is a decent neck, however, which I got cheap from a reputable dealer (H. Core). The next option for a neck is twice the price!

SO, I guess I have two questions: 1) Should I consider adding on a wedge of wood at the back of the foot?, and; 2) If so, how “permanent” of a join should this be? I’m pretty comfortable with using hide glue, but wonder whether to use epoxy – this is definitely not supposed to be reversible!

Thanks, in advance, for any thoughts and/or advice!

Paul (Eh_train
 

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#2
You could plane down the neck block and change the angle at the base. It's a lot more work but would probably be your best option.

If you do a shim, make it taper from the back of the neck joint all the way to the front. Otherwise there will be a gap between the block in the back on the neck joint and front making a crummy glue joint. I did a similar repair here, you can use it as a reference.
 
#3
Check your anticipated string length, and stop position, to make sure everything will work! also, removing any material from the base could weaken the heel.

The cut on the base of the heel, determines everything; String length, overstand, bridge ht., break angle, etc. Make a full size drawing to plan out the mathematics. Consider returning the neck, if need be.
 
#5
Thanks for your replies.

Cody, I see your point about planeing down the neck block, but it would weaken the area and I’d rather not do that. I saw the repair in your link, thanks, and hadn’t considered shimming the neck block. The neck block on my bass, however, is nowhere near as messed up as on that CCB you were repairing. Mine is quite clean and undamaged.

So instead of messing with the block, I want to ADD wood to the neck itself - a shim to increase the depth at the back of the heel. The shim would fill in the gap I created in my pic #2.

CT, I have checked the measurements, on paper, and think that the ‘enhanced’ neck (ie., the neck with the extra shim of wood added) will replicate the old neck. I will recheck the measurements, of course, and this all bears confirmation as I start to reduce the sides of the neck to fit the block.

Finally, Forester, although I admire some people’s ability at engineering a high tech solution, I first want to learn how to do a traditional repair (ie, to fit and properly glue a replacement neck).

Is there anything that jumps out as problematic about adding a shim to the bottom of the neck?

Thanks,

Paul
 
#7
I agree with CT on the epoxy route, I use T-88 epoxy, it's probably similar. You can get it at fine woodworking stores. You do not want those two pieces coming apart! I shimmed the heel of that crapo bass with cheap red cedar. (I guess you could say that I was actually shimming the neck block, either works.) Good luck!
 
#8
Hey Paul, I think your concept of adding a wedge to the face of the tenon will work out fine. I don't see why you wouldn't use hide glue - the neck is usually held in place with hide - but I would size the end grain of the face before gluing the long-grain wedge on there, just to keep the joint from starving.
 
#9
So.....I'm not tryng to get anyone worked up, but.....Let me get ths correct: you are going to take a vintage German shop bass, cobble it together with the wrong fitting replacement neck (orgin?- cheap and Chinese?), and then glue it back together wth epoxy and shims and hope everything goes ok??? Can assume you'll continue on the same path for the rest of the setup?

WHY??????

You can search through thousands of threads here and almost all of them tell you the same thing, over and over. Life is too short; if you are going to do somethng, do it right. If the neck doesn't fit right and you cannot fix it properly, get rid of it and get a replacement that fits correctly; there are plenty of places you can buy one that will work. The Chinese and other cheap imports have given us enough ill instruments built out of poorly fit materials put together with methods that don't pass the grade...

You can bring this instrument back to life in a generally accepted practce that will work now and will allow future repair people to maintain it for a long time after you are done with it, in a manner that will be clean, easy, and you'll be proud of. DO you really want to be sitting there in five years trying to explain to some future buyer that, yeah, I found this cool old German body that I thought had lots of potential and I invested a lot of time and life energy trying to fix it up, but yeah, you're rght, the neck looks like $%!# at the neck joint because I tried to fix the wrong blank, and yeah I couldn't fix it proper, so I epoxied the $%!# out of it, compromising any wood surface areas, so nobody will be able to work on it after me, and yeah, I asked around on several web sites and people who worked on basses every day told me I could do it other ways and use hide glue like the bass was originally built with and has been the tradition for many centuries for obvious superior working and structural reasons, but, yeah I took the easy way out, and yeah, but so what, now I want you to fork up $$$$ for my efforts, even though I know I could have done a better job.........

OR, do you want to be sitting there getting top dollar, and proudly telling all the reasons why you did it right, took no compromises, and followed a standard that will last and be user friendly for future repairs and feel great knowing that you did it correct, learned a bunch in the process, and rebuilt something that will outast all of us....

Just sayin'.....your old bass is like driving a nice vintage car. Some people do them up right and they look and drive great over the long haul; other folks take them south of San Diego, get the seats filed with hay and horse $#!@ to plump them up a bit, and then try to make a quick sale before everything falls apart again....

Aside from all that, remember that we are all just a bunch of dorks on the computer and, for now, the bass is yours. Treat it as you like......I know how I would restore it. The issues that you are facing and how you problem solve them are daily events for working luthiers. It pains me more than I can describe to see ( almost every week) a nice vintage instrument that had a lot of potential worked on incorrectly only to have the end result be something that nobody wants and because of all the short cuts it winds up being worth considerably less than if they had just left it alone....

'My apologies for any potential bad vibes. Basses are great; working on basses is great; and I want to see you bring it back to life in the best style possible.

j.
 
#10
Hi James,

Glad to have your opinion. I posted to get feedback, and want to take it all into consideration!

Just to reiterate, I DO recognize that the body is a nice piece of work, and that's why I don't want to mess with the neck block. I think the neck is generally considered more 'replaceable' (and remember the scroll was long gone before I got it, so impossible to preserve).

It is a Chinese replacement neck, and I'm sure I won't be the first TBer to install one (anyone want to open up THAT thread?). But it wasn't bought off EBay for $49, it was bought from Howard Core at more than 3.5 times that price. IF I use it, I plan to install CF reinforcement down the length of it before installing the fingerboard.

The one measurement problem that I have definitely found is in the neck angle, and the shim is one potential solution. Come to think of it, it might be the only solution other than a different neck, as the back of the neck needs more wood to fix the angle!

The idea of using epoxy (which some posters seem to be okay with) is to make the neck meatier where required. The idea of using hide glue (which I'm also okay with) to add the shim would still be to make the neck meatier. So, I think it really comes down to which is the better material for the job. I don't think using epoxy to beef up a portion of the neck would "infect" the rest of the bass. Likewise, I don't think using CF reinforcement in the neck will sully the bass. Instead, I hope the CF will bolster the sound and increase it's longevity.

Note, both the shim and the CF will be invisible once completed. I would feel obligated to tell people about them if I thought they detracted from the bass, but possibly wouldn't say anything about them if they were working as intended.

I said earlier that taking the stump out of the block was difficult, and it was. It's probably a 40 year old bass, and I'm not sure they used hide glue to put the neck in. There is still a little of this milky white glue to be sanded out. Particularly near the button, where a bad fit allowed the gunk to pool up. I promise that whatever neck I put in will be hide glued!

Cheers,

Paul
 
#13
I have not heard a single mention of string length. You need to be shooting for a specific number, and if you do so, removing wood at the front (as Dallas suggested) may possibly fall right in with your plans. Here's the formula: Stop + Neck + 1" = String Length. This assumes an average bridge tilt and overstand. Please post the stop length and the current neck length so we can better help you. There's more thinking to be done before the cutting starts. If the neck is a bit narrow, and you are committed to using it, you can glue thin strips to it on the sides, where it sits in the mortise. Also, start giving thought to how you are going to align the neck to the body.
 
#14
kurt ratering said:
why not fit some spruce into the mortise and carry on like it was a new block? the relatively sharp angle of the new neck will be backed by new spruce. if you do, just make sure the runout is alined to cooperate with the direction your cutting, ive messed that up before and fighting the runout sucks!
Click to expand...

This is the method I used on the bass you saw pictures of. I didn't add wood to the heel, rather used the cedar shim and glued everything together with hide. I would have used some good sitka spruce for the wedge if the bass were a more worthy instrument.

I would only recommend the epoxy if you want to add more hardwood to hardwood. And I'm sure you know not to glue the neck to the mortise with epoxy! James has a very valid point though. We luthiers have a responsibility when it comes to fine old instruments. It's an ethical dilemma for us and sometimes it's damn tempting to cross over to the dark side to save time and money. The epoxy route isn't traditional and it will have a negative effect on the sound, even if it's barely noticeable.

If you look hard enough, you can find the right neck for the right price. Most of the well-known luthier suppliers have great stuff, but they also fetch a steep (sometimes rediculous :mad:) premium. Though you might have less positive feelings towards James at this point, he's very skilled at finding tonewoods and would be a good person to ask about procuring a worthy neck.

This is all me thinking out loud. I'm not pointing you in any specific direction. If this bass came through my shop, it would probably spend some time on the shelf until I could find (or make) a suitable European flamed maple neck that was the right size for the job. The European maple will be a b***h to carve but I would feel better knowing that I matched materials to as close to authentic as possible. Even though it cost me more time and money, at least this way I'm a good curator as well as a good luthier..
 
#15
As a postscript, I wrote the prior note last night after working all day to clean up on a series of bad repairs on one old bass that were all a cumulative "add on disease'- do one thing poorly, so add on some extra to cover that , but the fix was kinda shoddy, so add on a little more for the first fix, when that fails, add on a little more, and keep going until the whole thing is such a mess that think it's time to anty up and go visit uncle james for damage control instead of my favorite 16 year old at the electric guitar shop (which was once me many decades ago....).....

Cody's idea of making a new new neck sounds like a lot of fun. I used to thnk doing that was an incredible pain, but these days, it is a nice peaceful excursion that also allows me to make the specs and measurements to any numbers I need. Why would I ever need to take up yoga or fly fishing when I get to hand carve beautiful woods all day long....
j.
 
#17
james condino said:
As a postscript, I wrote the prior note last night after working all day to clean up on a series of bad repairs on one old bass that were all a cumulative "add on disease'- do one thing poorly, so add on some extra to cover that...
Click to expand...

James…make no apologies for high standards. :)

One of the things I admire is the fortitude to do something with a passion and do it right. Fast and cheap is how we have ended up with a slew of cheap, broken, green, basses. If my husband has taught me one thing very important thing in 25 years is make no apologies for your high standards. Do things your own way and then be prepared for the consequences.

He also taught me the truth has only one version…if you always tell the truth you don’t have any versions of it to remember. Pretty cool and very common sense (Tiger Woods could have used this advice)... :D
 
#18
Hi guys,

Thanks for all the comments. James, no "bad vibes" taken! I want to figure out a solution that works, that's why I'm asking around. No basses have been harmed during the making of this thread. Maybe, after reading below, you will even sell me a different neck!

For the past 6 or so years, I've been fixing beat up ply basses that most of you would roll your eyes at. It's safe to say that in every case I've put them into much better shape than when I started (ie., I've made them playable again).

Now I am taking the next logical step to try my hand at slightly better basses. For the record, this bass has a carved top and back, with plain ply ribs (unfortunately not even any flamed veneer here). Nice enough, but nothing fancy. Cody, your suggestion of fitting a flamed neck might be ideal, but might also be overdoing it a little. The old neck stump had "flame" that was painted into the finish - pretty tacky really.

Arnold, yes I have been measuring. The string length, once I shim the foot or the block to create the correct angle, is 41". If I cut into the block at the front to correct the angle, I would lose a half inch of string length (which I'd rather not do)... I also have qualms about altering the body to accommodate the neck.

Some of the posts seem to treat whether to shim the neck or shim the block as essentially the same thing ("potato/potado"). I don't see it that way at all! Nobody responded to the notion of keeping the bass body robust, and treating the neck as less permanent. (Nobody responded to the idea of using CF reinforcement in the neck either, although I gather from other threads that many have done this).

If I add a shim to the neck, I am joining hardwood to hardwood in what should be a permanent bond. No matter how they are joined, this "beefing up" of the neck should be permanent. If I add a shim to the block, I am joining softwood to softwood in what seem much more like a temporary "reshaping" of the block. If you shim the mortise using softwood, it seems to me much more like what James calls the "add on" approach. Of course you can do a good job of it, but it still seems like a temporary (reversible) solution.

Finally, please note that when I said the neck width was 1/16th of an inch smaller than the original, I meant at the fingerboard gluing surface. The sides of the foot are still wider than the mortise. So I won't be "fudging" anything, or adding in little strips here and there, except for compensating for the neck angle.

Thanks for your patience. For some of you, there may be no two more horrifying words than "amateur luthier"! I am, however, passionate about this, and continue to make progress at my own speed.

Cheers,

Paul
 

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