Design Help: Neck Lengths And Such

Hello!

I am attempting a bass design sometime this summer, and I have been planning it out in CAD. It's a prototype bass that I may hope to produce someday if I ever am able to (Steinberger/Chapman inspired minimalism, but less brutalist). I may make another post regarding my design and whether my choices towards it are sensible or not (I'm trying a lot of different things with it that hopefully benefit the player). It has all went smoothly so far, but I've hit a large rock in the road.

Before I explain my problem, it's important to know that I am modeling my bass off of a 34" scale length, and using a neck pocket for a 20 fret Jazz Bass neck (I don't have the skill or resources to make a custom neck).

The issue comes when I try to place everything on the body, like the pickup cavity and where the bridge will be. Essentially, I can never know where to place anything in relation to the nut or bridge, because the neck pocket is dependent on the length of the Jazz Bass neck. If I was making my own neck and pocket, this wouldn't be an issue, but it seems I cannot find the actual length of a jazz neck from the nut to the very heel.

Am I missing something here? Do I absolutely need to know the dimensions of the neck in order to properly align where the bridge/pickup is? I'd imagine there is some sort of logical/mathematical definition for the nut-to-heel length of a jazz bass, but I haven't seen it.

 

Yeah, that's what I guessed. However, I am away from home right now and can't actually make measurements on the heel. I wish this was a little more defined, lol. I'm just antsy to keep working on this design since I've been wanting to get it out of my head for a while now.

 

Well, yes, but the problem still persists. There is a missing dimension, which **is** the neck. Because of the unknown dimension of the neck, there is no telling how large the body needs to be. When I say body, I am referring to the length from the bottom of the neck pocket to the end of the scale length. Obviously the size is limited by the position of the neck pocket and bridge, so that dimension is needed for the design to actually be fully constrained.

Imagine it as two lengths that add up to 34", and I don't know either of them. As a result, the joining point between those two lengths is variable, because that joining point (in relation to the nut) could be anywhere without having a fixed neck or pocket-to-bridge length. The scale length can't help here, unless the length of the nut to the heel of the neck is aligned somehow to the scale length, like Will_White suggested. Either way, I really can't find a fixed dimension for it online, lol.

 

Thank you, this is really useful, although I would like some serious comfrimation that it gets cut off at the 21st, since I was comparing dimensions from Warmouth 21 fret jazz necks because they have an overhang. The heel didn't seem to align at the 21st.

I am finally home now, and I measured two official jazz bass necks that I have. They consistently measured about 6 7/8" from the 12th fret, or 23 7/8" in total from the nut to the heel. I feel this will be a good base point for me to actually start finishing my prototype, even if it isn't the official length. Thank god for moveable bridges.

I will be modeling the bridge I will be using soon, which is a hipshot bridge (part 5A4FM1). I know its a drop in for a fender mount, but they are like 75 dollars on amazon, and that's a lot better than 120 for the hipshot 4 screw mount version of the bridge. Luckily, the maximum and minimum intonation points are listed in that pdf, which is nice, so I'll be able to design this based off numbers alone. CAD can kinda suck sometimes if you are designing independently, because model files don't always exist openly.

Either way, I'm super excited to make this thing. It's going to be the big thing I do with my dad before I move out, and I'm expecting this to be my main bass for the rest of my life. I'm also going to design a strat version of this design, and give it to him one day for fathers day, and I am already excited about that. Of course, this is only Mark I of the design, so it's based off external parts, Mark II (or whatever I get to in the future) is going to have hardware and a neck completely designed by me.

Thanks for everyone's help <3

 

I hope I even get to the point of building it, I need to find someone or someplace willing to let me borrow a CNC router.

 

Did that already, lmao. I emailed a makerspace about it and I'm waiting for a reply.

 

Pft, I WISH I had the tools to do that properly, but I don't, and my dad hasn't really done something like this before. We're on a budget, and if we mess up, it's not exactly cheap to throw away some messed up stock along with having to pay for all the tools, bits, all of that.

Some of the stuff will still be done by hand, like cutting out pickguard material to cover the electronics cavity, adding a fillet around the edges to smooth out the body, sanding and finishing, and drilling a few holes for hardware. Don't worry, some humanity will be involved. I also find what you've said to be a little ironic to me, as this is a prototype for a bass/guitar that I am hoping to mass manufacture one day, if I even get on the map. The whole idea here is to minimize the amount of material and complexity of the body so that same money can be put towards nicer hardware/electronics and a much better neck.

 

A quick update, I am having trouble finding someone or some place that will help me get the body routed out. Thankfully, my parents are awesome and are looking at options themselves, which is a big help. The design is fully completed, but I had to do a few changes to make room for the electronics I'm adding. All of my parts have arrived, and they are super nice!

I got a SMB-4A Seymour Duncan stingray pickup, a Hipshot 5A4FM1 bridge in brass, Schaller S locks, and a Switchcraft 3 way switch.

My plan for the electronics is to use the 3 way to select between the bottom coil, top coil, or both for humbucking. It's a stingray pickup, but I love how they sound passive and EQ's are stupid expensive. I even tried designing my own EQ circuit a while back, but that didn't really go anywhere. I won't be using a volume knob, since I don't find them that useful, but as compensation I will be adding a mute switch. The body is very very small, so ill have to see what extras with the electronics I can add since I don't even know if I can manage to get a mute switch to fit in there.