For anyone interested in a jig for getting started with frame building, check out the Jiggernaut. A couple of guys I know have always been tempted to build their own frames, but were always hung up on the cost of buying or making a jig. This is the inexpensive design they came up with, and you can get one for yourself on Kickstarter.
Disclaimer: I have never used this jig, I have no interest in promoting this jig other than seeing a couple of local MPLS guys succeed and seeing more people making their own shit, eh.