Hello everybody. So I've just recently started working for a local luthier, and came up with the brilliant idea that I should make my own bass, AND it seems that there aren't any forums about anyone building there own bass from scratch, so I guess I'll start one.
So here's a few Ideas that I've heard:
Ebony is good to be used for fretboards
Mahogany is a good wood for bodies and necks
Fretless basses have excelent harmonics
But as someone who's never built an instrument, here are some questions:
Should I use active pickups or passive pickups?
What pickups are better: Single Coil or Double Coil? And does it matter?
Must I use a preamp?
Does it matter what bridge I put on it?
Does a whammy bar REALY help?
Are there specific measurements for anything?
Are there certain techniques?
How do you make the neck? How do you fret it?
And so on and so on...
So anyway, please give some answers about these questions, and even add some.

I’m not a luthier, but I do tinker with repairs occasionally and I think the idea of building your own personal bass from scratch is excellent and encourage you to do so. You may not get it right the first time, but you’ll learn a great deal and perhaps the second or third attempt will be the bass of your dreams:

Ebony is good to be used for fretboards
(I agree, but Rosewood and Maple are also fine traditional woods for fretboards)

Mahogany is a good wood for bodies and necks
(True, as are many other hard woods, each with tonal qualities and esthetics that you can consider)

Fretless basses have excellent harmonics
(You may consider a bolt in neck and build both a fretless and fretted neck for your bass. Or like some old time banjos I’ve seen, build it fretless up to the 7th fret or so and fret the higher register)

But as someone who's never built an instrument, here are some questions:
Should I use active pickups or passive pickups?
(I like normal passive pickups)

What pickups are better: Single Coil or Double Coil? And does it matter?
(Either or both, generally Single Coil will be brighter with possible 60 cycle hum problems in some situations)

Must I use a preamp?
(If you use active pickups)

Does it matter what bridge I put on it?
(Luther’s choice. I’d pick one that was as adjustable as possible in all directions)

Does a whammy bar REALLY help?
(I don’t think you need one on a bass)

Are there specific measurements for anything?
(Fret spacing, relative to your chosen scale length and bridge position. Everything else can be flexible to your personal desire)

Are there certain techniques?
How do you make the neck? How do you fret it?
And so on and so on...
(I’m not qualified to give you much advice there. The local luthier you are working for should be able to give you some valuable instruction. Watch and learn as much as you can for as long as you can under his tutelage.)

Have fun and good luck!

Ebony is good for fretboards, but rosewood or some of the other Brazilian and tropical woods are nice in that they give you some grain to grind against bending notes, or sliding on a fretless neck. Ash, alder, maple and other hardwoods would probably be preferable to mahogany for bodies and especially necks. For your neck you ideally will laminate a blank with perhaps 3 layers of a good hard wood running 90 and 180 degrees fron the wood of themain blank. This combined with a truss rod will ensure the rigidity of the neck; many builders like to run this lamination through the body (neck-thru construction) which has the effect of making the guitar 1 piece and vastly improving sustain....Active pickups are desirable for recording work, although the battery thing can be a drag. I would personally stay away from shorter scales unless you have very small hands. the scale length of a Fender P or Jazz bass is a good one to emulate and allows the low strings to sound their fullest. Shortscales (Gibson EBO, etc ) just dont have that big bottom that we love. I you are building from scrath you might want to consider a 5-string; we love our lowB! Good luck! Peace and Love lMW

I'm including a link to BGF (Brown Guitar Factory), as the neck is unlike anything I have seen. I don't have anything to offer on constructing your own, although I have put together a couple of "Frankenstein Fenders", I haven't made anything from scratch. Enjoy.
youtube.com/watch?v=W-9wY57AZIs