Back in the 60s, when I started making banjos, I designed and built a guitar as my Industrial Design thesis at Pratt. In those days, there was NO information available about how to do that - hard to understand in these days of information overload. I read about how to make violins and talked to people in New York who were making guitars, like John D’Angelico and William Del Pilar.
What I realized is that banjos are more metal than wood - more of a machine than a “musical instrument” I remember joking about that at the time.
The point is that you have to learn how to be a competent metal worker or you will be a slave to the companies that make metal parts.
FORTUNATELY, most banjo parts are made of some alloy of brass, which is easy to deal with.
This is going to be a long thread, because here are all the metal parts you have to make - not counting hooks and nuts: I might break it into sections - metal working, bracket band, tone ring, tension hoop.
Banjo brass parts are rarely wider than 1”, which makes it easier. You have to have some kind of bending tool that can bend strips and hoops of metal into relatively accurate circles.
The Harbor Freight ring roller, generally lacking in quality, is the best thing you’ll find, and you’ll have to modify the rollers:
Once you can roll things into accurate circles ( you can do it by hand, but it’s time consuming) you need to learn how to silver solder or braze metal parts. Regular solder won’t work, and stuff that’s called “silver solder” is often a joke. You are operating in the 1100 - 1500F temperature range - be careful - count how many times I say “be careful” Don’t ask me why I say that.
You need to use actual “silver brazing rods” The silver content reduces the flow temperature, but raises the cost BIG TIME.
Make sure it doesn’t have cadmium in the alloy - be careful:
For a brazing station, it has to be fireproof and well ventilated with refractory slabs to use as a base for brazing - these have to be coated with “kiln wash” - be careful:
It’s better to do it outside if weather permits - you don’t want to breathe this s***:
You need a “pickling” solution to clean the scale off the brazed parts, and the safest one is called “Sparex” - it’s an acid - be careful:
SO, You clean the parts, brush flux on the mating surfaces, heat it up with a torch (mapp gas will work for banjo parts), and flow the solder into the joint:
The joint gets all black and oxidized from the heat and flux - this is called scale.
You dip it into the pickle and it gets clean and pink, with a copper flash, which I’ll discuss later - when you clean it up, you can barely see the joint:
The joint is practically as strong as the metal itself, and equally ductile (which is a result of the quenching in the Sparex) - here I am bending the sample with no problem:
Next - on to the real stuff.