I tried asking this on /mus/ but no one has replied, so I'm gonna try here.
So I have recently started the planning phase for an electric guitar based off of some designs I saw for halo's guitars. I couldn't find the specs for any of the sizes so I kinda mixed up various specs I found for different electric guitars.
For the head stock I have 3 2/4" wide, 5 9/16" Long, 9/16" thick and 1 10/16" wide for where it connects to the neck.
The body is 21" long (probably gonna shorten it), 14" wide, 1 22/25" thick
How long and thick do you think the neck should be and should I change any of these.
The absolute first thing you should do when planning to build a guitar is to draw it full size (including any planned hardware, to scale), with a straightedge for the bits you want to be straight. You'll want a top-down view, a side-on view, and a full-size drawing of any pockets or interesting features that you plan to put in/on the thing.
This step, by itself, will answer most of these questions. If the drawing feels too big, then redraw a line smaller and work the design until you've got an outline for a playable instrument.
Have you decided on scale length? Do you have hardware you want to design around, or do you plan to get hardware and electronics based on your design? Do you know what sort of control scheme you want?
The reason I'm being a little obtuse is that it isn't exactly possible to answer your question based just on what you've asked. The measurements you have could as easily describe a box as an extra-thick telecaster.
Were you planning a tilted headstock? Set neck, neck through, bolt-on, or something in between? If you were going to tilt the headstock, would you do a one-piece neck or use a scarf joint?
First, yes, it is going to be a tilted headstock with a neck through one piece neck, sorry I didn't include that, also the scale length would be 24.75". And I do realize that I would draw out my design first, these measurements were just so I could make that phase go way faster then drawing and re-drawing. I just wanted to know if my measurements seemed too large or too small for what I had in mind, that's why the picture is there, its the design i wanted minus the shark fin inlay. Sorry if this reply sounded snarky, I feel like it did when i don't want it too.
sorry, forgot to add that yes, i would be getting hardware to accommodate my guitar, and also the layout would be like a traditional gibson, aka. 4 knob. the shape is what you see in the picture btw.
If you got general body size as sort of an average of other guitars, you'll probably be close right away. I don't mean to discourage you, but you should know that a neck through build for your first is a difficult place to start from. I'd recommend a bolt on, just to get a feel for the general process, first. Wood is cheap, though. Go get some 2" pine (or whichever 8/4 hardwood is cheap locally) to rough out a prototype and check your skills before committing a saw to the expensive and pretty stuff.
Haven't built one yet, but have researched like crazy, so take the following with a grain of salt (or flame away, your choice). All the body dimensions, within bounds, don't really matter. It's a taste/ comfort kind of thing. You'll always find someone that pulls out tonewood and resonance and shape arguments, but you can play it even if it's a big assed square. The biggest thing to check, and recheck, is the angle and height where the neck meets the body, whether it's a bolt on or a neck through. That's what determines your action height and ultimate playability. With a bolt on you can shim it or shave it and get it right, you basically get one shot with a neck through. As to the neck width, that's going to be determined to a great extent by your bridge anyway. Thickness and contour are based on what feels comfortable to you. Like I said though, I haven't built one, so I could be full of shit.