Step 1: Introduction
Commercial jigs start at about $1600. For the beginner this could be a huge investment - the equivalent of many bicycles worth of tubing.
There is also the option of building a jig out of 8020, such as described in my Instructable here. However, the cost on this is also not trivial, probably $350-$500, and it does require some machining work that is outside of the common garage tools.
If you ask around on the internet, many people will tell you that you don't really even need a jig, you just need a flat surface and some sort of tooling to hold your tubes at a fixed height above the surface. This is quite true, but for some people using an old pool table or maybe a surface plate is not exactly convenient, due to the size and weight.
This design and method is what I developed over building my first 5 frames. It's compact and cheap, and works by giving you a system of 3 small orthogonal flat surfaces to work with, and several means of holding tubes at the right position while you tack them.
However, since this jig is compact, you can only work on one joint at a time. This is the standard way for beginners to build, as described in the Paterek Manual. If you haven't heard of it yet, it's essentially the beginning framebuilder's bible. You can purchase it from Paterek or Henry James. The main disadvantage on this is that you never see the complete picture of the frame until you tack in the last tube. You can't set it up and then have a sanity check where you can see if it all makes sense.
I no longer have this jig, having moved on to my 8020 design, so I had to reproduce everything in SketchUp. For the sake of speed, I didn't model everything exactly to scale or try to make everything look perfect. But it should get the idea across.
If this Instructable helps you out, you can always show your appreciation through my Amazon Wish List.
Speaking of books, you might also want to check out Atomic Zombie's Bicycle Builder's Bonanza. While it doesn't cover classical framebuilding like the Paterek Manual, it does have lots of good ideas for "low road" building.
The materials are simple steel structural shapes:
1" x 1/4" bar, about 6", though get a foot since you'll eventually use it.
4"x 3" angle iron, give or take an inch in either leg, about 7-8' total
1"x 1" angle iron, another foot or so
Old rear hub axle(s) or similarly sized threaded rod and nuts
Some bolts, about M5 x 40 or whatever you have taps for.
A couple of Welder's magnets, available from Harbor Freight for cheap.
For tools you'll need a hacksaw, a drill and bits, and a tap to match your bolts.