Refretting and repositioning the neck on a neck through

[Beej]

Ok, just wanted to be sure you had checked in real life, as the lines on the computer are confounded by parallax in the digital photos and from not being able to take a fully direct photo of the entire instrument. As a result, you cannot rely on that method at all. It could give you an approximation at best, but for real-world, you'll need to make comparative measurements in at least 0.5mm increments.

 

[Fynn]

It might be difficult to tell, but this is essentially what I did with the string too.

 

[Beej]

It might be difficult to tell, but this is essentially what I did with the string too.
View attachment 5441892

Yes, but the best way will be a straightedge down the side of the neck. I can see a curve to the neck in the photo. I've exaggerated it here, but this is quite visible on my 60" monitor.

In order to rule that curvature out as an artefact of the digital image, you'd have to test it in real life. I'm suspicious of the curve being in the neck, as it's present in all photographs of the neck that you've put up, including from other angles. It may all be an artefact of digital imagery, hence my suggestion of ruling it out with straightedges.

 

[Fynn]

Yes, but the best way will be a straightedge down the side of the neck. I can see a curve to the neck in the photo. I've exaggerated it here, but this is quite visible on my 60" monitor.
View attachment 5441908

In order to rule that curvature out as an artefact of the digital image, you'd have to test it in real life. I'm suspicious of the curve being in the neck, as it's present in all photographs of the neck that you've put up, including from other angles. It may all be an artefact of digital imagery, hence my suggestion of ruling it out with straightedges.

I think I know what you mean, and I believe that's just due to my poopy handywork. I don't have a straightedge that long, but I have a machined piece of wood that goes almost the entire length of the neck. I just did a quick check, and I checked with my eyes too. I think it's just valleys and bumps that I have sanded into the neck while working on it. Which isn't great either, but I don't think that is the cause of the neck being crooked in relation to the bridge. When building the neck, I glued the fretboard to a square piece of wood, marked the center line, and the edges of how I want the neck to taper, and then cut it on a table saw, with one of those guiderails that you can tighten to the sawtable. I had a line drawn with pencil, that surely was straight because it was done with a ruler and checked multiple times, and the guiderail was obviously straight. That's how I cut the taper from the butt of the neck to the headstock (or what was supposed to be the headstock before it was actually glued together) I then glued the center block and the wings on it, and then I carved out the neck shape. But I didn't change the taper of the neck after that.

I had a bunch of pictures I did during the building process, but I currently don't know where they are. I might look for them to see if it's possible to see where I messed up, but I didn't take them with precision in mind anyways, so the perspective might not allow to tell if something is actually off.

 

[Fynn]

There is a clear bump at around the 6th fret, on the top side (G string side). But on that same spot at the other side, there's also a very slight bump.

This might not be the most accurate way to show, but this is the best I can do at the moment. I can use an acutal straightedge in better light at some other time, but I think this is fine for now.
The sanding block goes from the 1st to roughly the 18th fret, where the neck meets the body on the E string side. There are tiny tiny gaps in between the block and the neck, which you can't see on the pictures, but over the length of the neck before it meets the body, it seems to be pretty much straight.
Unless I'm missing something, which is very possible, but I checked multiple times.

 

[1n3]

... I'm not asking for the easiest way out of this situation, but rather the easiest way to fix my previous mistake and redo it properly.

If you want to re-do the neck because that feels more correct, I can't argue with that. But I think fixing the bridge would be much easier, and perhaps, better. And I don't think you're that far out, per this illustration. Here, the E and A strings pull left, D and G pull right. But the trem bar has some play side-to-side. If the left-right forces aren't equal, it will still move to one side.

 

[Fynn]

If you want to re-do the neck because that feels more correct, I can't argue with that. But I think fixing the bridge would be much easier, and perhaps, better. And I don't think you're that far out, per this illustration. Here, the E and A strings pull left, D and G pull right. But the trem bar has some play side-to-side. If the left-right forces aren't equal, it will still move to one side.
View attachment 5442327

That's an old picture. That was right after I finished the bass, and I haven't set up the bridge correctly yet. On the first picture I posted in this thread, you can see that with the correct string spacing, all of the strings pull to the right. The E saddle is actually maxed out all the way to the left, and I still feel like I could give it a bit more, if I wanted to.
I'm maybe a bit too ocd for this. Which is why I want to redo do it correctly. I just don't like the thought of the bridge being that much off center.

 

[Beej]

The point of the full-length straightedge from nut to saddles, is to double check their alignment - you can't really do that without a full length edge. You can do it with a laser too. Incremental measurement of sections will only tell you if that section is straight, but not the overall edge. 0.5mm neck movement left or right at the nut will translate to much larger distances from center at the bridge end. I'm not trying to belabour this, but in order to tell if it's straight, you'd have to put a full-length straightedge from nut to saddles. Right now, it has not been ruled out. It doesn't have to be a ruler, just something you know is perfectly straight along that length. A piece of factory-cut MDF would probably be fine, but I would not use anything else made of wood unless it's been CNC'd to that shape.

 

[Max Bogosity]

For comparison purposes like this, a straightedge could be as simple as a piece of string stretched between two fixed points.

 

[Fynn]

The point of the full-length straightedge from nut to saddles, is to double check their alignment - you can't really do that without a full length edge. You can do it with a laser too. Incremental measurement of sections will only tell you if that section is straight, but not the overall edge. 0.5mm neck movement left or right at the nut will translate to much larger distances from center at the bridge end. I'm not trying to belabour this, but in order to tell if it's straight, you'd have to put a full-length straightedge from nut to saddles. Right now, it has not been ruled out. It doesn't have to be a ruler, just something you know is perfectly straight along that length. A piece of factory-cut MDF would probably be fine, but I would not use anything else made of wood unless it's been CNC'd to that shape.

I'm not sure what you're trying to tell me honestly. I checked the sides as I showed in the pictures, and I checked with a taut piece of string in different positions. That definitely went all the way from bridge to nut, from nut to the end of the center block and so on. The piece of wood I used to do a quick check is a machined sanding block. It's about as straight as you can make a piece of wood with normal means. Sure cost as much anyways.
And even if the neck is actually bent in one direction, what would I have to do differently? If I want to actually fix the problem, I would have to remove the neck either way, right? And when you check the pictures where the bass is strung, you can see that the strings go along the edge of the neck straight. Not 100% perfectly straight, and the fretboard is kinda wonky after the 14th fret on the E side, but the deviance you see, is probably due to my shoddy fretjob (the frets aren't correct length, the fretboard is kinda messed up at the edge, and that might cause it to look like there is a bend in it), and happened after I already glued everything together, where I didn't take much material off the neck anymore, and didn't change it's overall shape.

If I'm going to refit the neck, I would mark down where the bridges saddles should be on the center block (in it's ideal position and probably use the actual bridge as a reference, and then use string from the nut slots of the respective strings to the specific saddle position. And if any of those are off, for whatever reason, then I could work from there. Unless someone has a better way of checking for that. But that would at least ensure, that if I were to glue it in a position where all the strings are centered correctly relative to where the bridge currently is, that it would also work with actual bass strings just fine. And if I then realize that the neck is a banana, then I wouldn't have to be sad, because the neck would have to be removed anyways. Or is there something wrong with my logic?

I sure do appreciate every help I can get, I definitely asked for it, but I'm not sure how what you're suggesting would make my situation different anyways. I'm definitely not gonna reshape the neck, because it's about as thin as I want it to be, and any more material removal would make it too thin.
If the edges of the fretboard are still too crooked after I radiused it, I'm probably gonna remove it and put a new one on anyways. Worst case scenario for me would be if the actual neck itself isn't salvagable, because I put a lot of work into the neck profile, and I'm really happy with the way it currently feels...

 

[Beej]

It all comes back to it being much less work to infill the bridge rout and cut a new one than removing and reattaching the wings, so it's about saving the time and work. To be clear, I could totally be wrong, my suggestion is just around accurately assessing the issue so you can proceed in the most efficient and least destructive manner.

I guess I'm wondering if it's a neck alignment-to-the-body issue or a "neck has a gentle arc from nut to butt" issue. Putting a full length straightedge can immediately show which one it is, in a way that a string can't (as a string is not rigid). I'd put a straightedge from the nut down to the saddle line (scale line) and mark it on both sides. Directly in the middle of those marks would be the center of the neck beam and the point over which your strings need to be centered. That will tell you right away if your neck is centered in the body or not.

If it is centered in the body, then the quickest and easiest way to repair would be to infill and reroute the bridge and leave the body/neck joint as-is. This approach is much less work than cutting the wings off and realigning them.

Connected to this is my wondering how the wings could have been misaligned in the first place such that they would throw off the bridge alignment... Because it's a neck through, the beam is automatically 'straight' if it's tapered evenly side to side. You can then glue on wings and move them towards or away from the 'butt' and they can't really impact the alignment. Regardless of where they are, they will end up parallel to the neck beam.

Anyway, I don't mean to talk at cross purposes, I genuinely only wish to help here. In the end, no matter what approach you take, I'm all for it too, as every build, every problem we solve, only serves to increase our skills and knowledge.

 

[Fynn]

It all comes back to it being much less work to infill the bridge rout and cut a new one than removing and reattaching the wings, so it's about saving the time and work. To be clear, I could totally be wrong, my suggestion is just around accurately assessing the issue so you can proceed in the most efficient and least destructive manner.

I guess I'm wondering if it's a neck alignment-to-the-body issue or a "neck has a gentle arc from nut to butt" issue. Putting a full length straightedge can immediately show which one it is, in a way that a string can't (as a string is not rigid). I'd put a straightedge from the nut down to the saddle line (scale line) and mark it on both sides. Directly in the middle of those marks would be the center of the neck beam and the point over which your strings need to be centered. That will tell you right away if your neck is centered in the body or not.

If it is centered in the body, then the quickest and easiest way to repair would be to infill and reroute the bridge and leave the body/neck joint as-is. This approach is much less work than cutting the wings off and realigning them.

Connected to this is my wondering how the wings could have been misaligned in the first place such that they would throw off the bridge alignment... Because it's a neck through, the beam is automatically 'straight' if it's tapered evenly side to side. You can then glue on wings and move them towards or away from the 'butt' and they can't really impact the alignment. Regardless of where they are, they will end up parallel to the neck beam.

Anyway, I don't mean to talk at cross purposes, I genuinely only wish to help here. In the end, no matter what approach you take, I'm all for it too, as every build, every problem we solve, only serves to increase our skills and knowledge.

Well, it's not exactly a neck through. It's more like a set neck with extra steps. Which is why I fear that I might have messed up during that part.
The bass essentially consists of 3 parts. The neck, the center block, and the wings. The neck is attached to the center block via another piece of wood on the back, and then the wings are glued on the sides of that construction.

 

[Fynn]

I found some of the pictures I took during the build. I did notice that I had drawn a center line, and actually two lines along the edges, on the fretboard. Those were probably relics from when I cut the taper of the neck. So I'm certain I drew lines to check if the neck itself is straight. But there's no markings at all on the center block. And I can promise you that I drew those lines with a metal straightedge. Assuming the lines were close to straight, the fact that I still could see them after having sawn the taper into it, should mean that I didn't saw a banana shape into it, at least not in that stage. I usually draw the lines a bit inwards, so that I don't remove them with the sawing and am able to tell if I was going correctly.
I actually just found a picture showing the neck without the center block attached. The neck already had a taper, so I used the table saw with the guiderail to saw a taper into the neck, before I even attached it to the center block. So potentially after gluing the centerpiece onto the neck, I must've messed up while sawing the taper into the center block too. Which serves me right for not doing the whole thing in one go after having glued it together I guess...

So either I messed up three seperate times with a straightedge on the neck, and my current rough measurements are wrong, or I messed up while using the table saw cutting the taper into the block, and didn't notice the whole time.

I think I remember the reason for why the bridge isn't centered though. I had the centerline of the bass for almost the whole process, but never drew it onto the centerpiece. I just assumed that having glued it to the straight neck, and having cut a taper with a table saw into it, must've meant that I couldn't possibly have messed up. So I didn't have any reference for the actual center of the neck, and instead just assumed that the whole thing is correctly tapered and the middle of the center block must be in line with the middle of the neck. That was a stupid assumption.

 

[Fynn]

Maybe my next build just won't involve any contrasting wood pieces that need to be lined up correctly. Doesn't matter visually where the bridge needs to go, when the body is made out of one piece of wood heh.
Or I just learn to do it correctly...

 

[Fynn]

Alrighty, I don't know if anybody is still gonna see this here, but I've made some more plans. Took a longer break from this, because I was busy with other stuff. I'm going to cut up the bass, but I'll do something else along the way. I do want to reposition the neck, but I also want to make the neck a bit wider.

I looked at the bass again and again, and realized that the taper of the neck isn't correct. I didn't have the measurements in my head after I made the bass, but I realized that the neck doesn't get wide enough towards the body. The nut size is pretty much bang on (about half a mm thinner than I originally planned, which is fine), but at the 29th fret it is definitely too thin. It's at about 5.7mm, while it should be around 6.1mm. That's quite a big difference, and it's also annoying me. Generally speaking, I'm not happy about how the whole neck is. I still would like to try and salvage it though.

I'll be buying myself a new metal jack plane, and spend some time learning how to use that just generally, so I can 100% make sure that everything is level and straight. My plan would still be to saw off the wings, but then to cut a strip of material off either side of the neck, to then get the plane and try to make both sides as straight as possible. My idea is to then glue long pieces of maple onto those sides. The idea with maple was that I think it would be a nice contrasting wood to the fretboard, but also make it so the neck can be the correct intended thickness and have the correct taper. I would cut into the neck too, but I don't think that should be a problem when I have the maple overlap the mahogany and the wenge, right? It might look a bit odd, but I think it would generally look fine. These maple stripes could technically go all the way through the body, which would ensure that if I don't mess up that part, everything should be seated straight and correctly. I would also take the opportunity to clean some other stuff up, but that's not really important.

I've got two concerns really. One is how I would go about actually removing the material from the sides of the neck. My current idea is to take a pretty fine saw, mark two lines on both sides that would show me the correct taper just a bit inside, so that I would add the correct amount of material on both sides after with the correct taper. But I'm not quite sure if I'm missing some glaring issue with that approach. I don't exactly know how I would go about marking the other side of the neck, since it's a rounded piece. Maybe just eyeball it and live with the fact that the maple is a bit thicker on the underside if I really mess up?
The other concern is how I would go about gluing the body back up, given that the wings on the body are such a weird shape. I would imagine correctly positioned clamps would work, but I don't want to damage the wings. Maybe I would have to put some thick piece of cloth under in between the clamps and the body pieces.

All that being said, I really want to do it this way, because if I don't do this, I'm just gonna be mad at how poorly I made that neck. I'm either gonna try fixing it and succeed, or I'm gonna horribly mess up and make a completely new neck.

Besides the jack plane, I also plan on buying some other hand tools, and some sharpening supplies for the old chisels I've been using. My idea is to not rely on any bigger powertools anymore. I think for me that's the best way to go, because I can go slower, don't have to protect my hearing for the most part, and don't have to fear making a mistake with a tool that could hurt me or the work piece massively. I also think it's kinda neat to do everything like that.
Part of this whole journey is making my dream instruments, but it's also about learning how woodworking in general works. I planned on doing some other more simple projects too, which are not related to music. I've spent the past couple weeks watching videos from some of those big woodworking youtubers, like Paul Sellers and Rob Cosman.

 

[T_Bone_TL]

In the "other hand tools" line, buy a nice long straightedge (a 4 foot level is one way that's commonly inexpensive) and either buy or make a "marking gauge" which is a very useful adjunct to hand planes, and both will help with getting lines to plane to. Or get techy and use a laser for the straightedge layout jobs - some folks do.

I also think you've either measured in centimeters and labeled it millimeters or otherwise have your measurements off by a factor of 10 as written, or the confusing mixture of "wide and thin" rather than "wide and narrow" .vs. "thick and thin" is confusing me about what you are actually adjusting, but the rest of the post sounds like it is width, and a neck 5.7mm wide would have a hard time supporting one string. So I think you are trying to go from 57mm wide at the heel to 61mm at the heel. After all, 5.7 to 6.1 is also less than half a mm, which you consider no big deal at the nut end, but you're saying it's quite a big difference at the heel, so 4mm seems more likely than 0.4mm

 

[Fynn]

In the "other hand tools" line, buy a nice long straightedge (a 4 foot level is one way that's commonly inexpensive) and either buy or make a "marking gauge" which is a very useful adjunct to hand planes, and both will help with getting lines to plane to. Or get techy and use a laser for the straightedge layout jobs - some folks do.

I also think you've either measured in centimeters and labeled it millimeters or otherwise have your measurements off by a factor of 10 as written, or the confusing mixture of "wide and thin" rather than "wide and narrow" .vs. "thick and thin" is confusing me about what you are actually adjusting, but the rest of the post sounds like it is width, and a neck 5.7mm wide would have a hard time supporting one string. So I think you are trying to go from 57mm wide at the heel to 61mm at the heel. After all, 5.7 to 6.1 is also less than half a mm, which you consider no big deal at the nut end, but you're saying it's quite a big difference at the heel, so 4mm seems more likely than 0.4mm

Yep, I meant cm. It's something I do quite often when I write stuff down. I mix mm and cm constantly. Luckily in the real world that is quite obvious. Though I usually just correct it in my head without noticing. Because I wrote those measurements down, my brain knows what they're for, so I'll just think 5.7cm, even when I wrote down mm.

I have a 1 meter steel ruler on my list. Not necessarily as a level, but because I wanted something that is easier to use than a tape measure. Marking gauge is also on that list! Lasers are also a cool idea, but I'm assuming they're not very cheap.

 

[Fynn]

I should probably just stick to writing everything in mm. I could also go with zoll, or as you know it, inch. Almost every precision tool I've seen here has both cm/mm and inch on it.

 

[T_Bone_TL]

Lasers have become quite inexpensive, particularly red ones. But if you're buying a ruler to combine the jobs of straightedge and measuring tool, no need.

The level (for luthierie) is not used so much for level, as for a relatively affordable and inflexible straightedge (or sanding beam) that happens to be a level (so it gets mass-produced and brings the price down relative to other options,) but no need if you are buying the ruler.