Frame

First, I designed the frame using SolidWorks and making mock-up models of the components that will go along with it to make sure it all fits together. Here's a screenshot of the frame design...

I then built up a jig using some scrap wood. It may sound cheap but that's exactly what it is, it's cheap but also made precisely and works great.

Next it was time to get down to business with cutting and notching tubes. Then, using the jig to aid, welded them up and got to see the frame begin to come to life.

On day three of building the frame I started working on the overhead roll bars and supports. First, using a simple jig-like setup (pictured below), I welded on the front uprights. 

Then, using the same kind of jig setup as I did on the front, I welded in the rear hoop along with the second rear crossbar.

Day three wrapped up with welding the top two tubes, the tubes that connect them to the rear hoop, and a support on to finish up the main frame of the roll bars.

Day four again came with a lot of progress. I first started by welding up the side protection tubing, using the solidworks drawing to get all the correct measurements from. I then welded up the top and rear X's to add support and rigidity to the frame.

I then started on the lower side diagonals that will eventually go around the entire left and right sides but only got two of the eighteen that will be needed done.

Here is a picture showing where the build is at the end of day four.

On day five of the build I added many more of the lower diagonals, finished the bottom X, and added in another side protection tube on both sides to provide better protection to the driver and passenger if the vehicle is rolled and also give the previous single side protection tube more support.