Do you have all the necessary tools and skills to fab something like this? I've started building my own addition to the factory rear hoop in my '05 LJ Rubi here recently. I've never attempted something like this before, and now that I've started, I've realized I don't have all the necessary tools myself. I'm building everything from scratch, measuring probably 30 times before cutting, then test fitting, marking, grinding and doing it all over again before tacking it in place for welding. The one tool I was missing was a tubing notcher. I figured I could make my drill press work, but that was a no-go, ended up with a sheered hole saw bit and a mess of a practice cut on a small end-piece. Ended up using the grinder to make my notch-which was a REAL PITA to fit perfectly. Finally got it, but man was it tough. Thankfully my buddy from JT's Differentials had a tubing notcher he let me borrow tonight, so I'm hoping I'll make some headway with it now.
I haven't seen or read any "how-to's", so everything I've done so far is out of my head, and what I think will work, or what I "HOPE" will be strong/stout enough to handle a roll should it ever happen. The only real write-ups I've seen was Besrk's great buggy build project-which actually inspired me to sack up and try my own cage. If you haven't seen it-do a search for it, it's an awesome project he did an OUTSTANDING job with. My hat's off to him-great work!
For my project, I started with some 3/16" plate that I had bent to a 2"x6" piece of angle iron basically. I screwed up there because I didn't check my dash angle first, and had to back it out about 6 degrees, as the dash contour is about 84 degrees-not a true 90. What I wanted was a platform above the dash to start my tube work from, that would fit along the door jam, and tie into the floorboard- similar to the Poison Spyder Customs design. With my piece bent right, I then traced out the contour of the dash, as well as marked all the bolt holes, striker cut out, tub indent, and electrical panel notches that needed clearance to fit. With this done, it became more and more of a test-fit procedure of marking, grinding, fitting and repeating the whole process over and over again until I finally got the pieces to fit between the dash and door so that the doors would close, window cranks would work, and dash vents would function.
With this done, I then made some "L" shaped plates-again out of 3/16" plate (everything in my dash pillars is 3/16" plate), and recessed them back flush into the main support beam. This piece went up top, and outlined the dash vents on each side of the rig. I then overlayed that with a piece of flat plate that covers up the square section of dash-roughly 4" wide by 5" deep at the corner of each windshield/dash section. This basically forms a front, side and top for the tube platform to begin. I didn't think that would be strong enough in itself, so I flipped the piece over, and did some fitting to finally get a piece of plate roughly 1 1/2" wide that I angled at about a 45 degree angle on the underside to join the flat plate with the side beam, and tie into the front "L" bracket. With that support piece in place, I then boxed in the back end so it's all solid, totally enclosed. The top section is now finished.
For the "feet", I trimmed the main pillar down to about 3.25" in depth from the original 6" starting point, so it would be easier to get in/out of the rig. -don't forget it's angled and still has material on the other face for extra support. I decided I wanted to tie the dash pillar into my Rokmen slider backing plates, which bolt the sliders to the floorboard, so I notched out another piece of plate to contour the bottom of the tub, running from the side wall, around the fender area and up front a ways to reach my furthest slider backing plate, then back to reach the double-plate just in front of the seats. My goal was to retain ALL factory options/features, so I also notched out around the factory drain plugs, so they are still serviceable. Naturally the tub isn't flat, and had a bit of a drop to it, so even though I had plenty of overlap at my slider backing plates where I wanted to be, I couldn't reach them because they were lower than the main foot of the dash pillar. I had to make a "step" basically, and weld them fully to the main "foot", then to the backing plates. Made for a lot of hassle, a lot of extra work, and a lot of headache trying to get "just right". Keep in mind, this is just for ONE side-still have the other to go!
With the dash pillars done, yesterday I was able to move onto the windshield bar from the main hoop. This required fabbing up some brackets to match the stock ones that bolt in at the rear hoop, as well as the front windshield. The front windshield needs to be bolted in, but the rear hoop I left bolts for now, and will later go back and weld it solid when everything else is finished. The bracket fabbing wasn't too bad-lots of sawzall and grinder work. I don't have a plasma cutter which really sucks-would be much easier with one of those.
With the brackets made, I was FINALLY able to start my first piece of tubing-the upper windshield bar on the passenger side. This turned out to be much more difficult than I originally thought, as there are so many angles to deal with. Not only is it angled about 24 degrees off vertical, but it's also angled about 10 degrees down to the right at a funny angle there, which made cutting for a snug fit interesting. Naturally the rear was a chore too, though thankfully it was only about a 10 degree angle with only a minor drop outwards. I should note I'm using 1.75"x.120 DOM tube for the cage tubework.
The next piece I moved onto was the first windshield vertical tube-tying my dash pillar to the upper windshield bar. Should be easy enough right? I wanted it to follow the lines of the Jeep as exact as I could, so that meant a 26.5 degree angle at the base plate/top of the dash pillar, then the corresponding angle at the upper windshield bar on a piece of tube about 14 3/4" long. First flat cut no problem. Moving onto the notched section-major PITA! I had no tubing notcher and had to rig something up on my drill press, which unfortunately failed miserably.
Actually, I think I got a defective hole saw that I bought earlier in the day-I've never seen one shatter and throw teeth everywhere like it did, so I'm going to blame that problem on the bit itself. I think the jig I rigged would have worked fine with a good bit. As the press didn't work, I had to notch the tube with a grinder-which was a REAL PITA and a REAL time consumer. Finally got it to fit/work and after several test-fits and touch-up grinding, I was able to get it at about a 27.5 degree angle. Not perfect, but I figured 1 degree difference in this short section would be OK. It fit, looks good and should work good.
Tomorrow I hope to move onto the driver side upper windshield bar and vertical windshield tube. With my buddies tube notcher, and more strait pieces to go, I think the next section will be MUCH quicker to fit/notch/grind and tack into place prior to final welding. I think I've got the biggest/hardest parts out of the way-finally. I will have to do some bending, but that will come after the main strait sections are in. Things could get interesting there, but that will mostly be measuring difficulties I think. The bender I made is working fine, so I think it will be more of figuring out where to mark the tube to start the bend that will be the biggest problem.
Anyway, sorry for the length of the post-VERY long winded, I know. Your question sounds as if you may be in the same boat as me-never done something like this before. I wanted to give you an honest opinion of the labor involved on your "first" cage project. For an experienced fabber, it's probably no big deal at all, but starting from scratch with no idea how to do it or where to start could be a little intimidating for the faint of heart. I definitely wouldn't recommend it as your first major project either. It's definitely not something you're going to do in a day-or even a weekend for that matter. Well, possibly if you are just slapping tube together, but if you actually take the time to do it right, it will take time-as well as patience, and lots of it. There have been several times now I've seriously thought about just giving up and forgetting it due to frustration, but then my wife comes out and says how great it looks so far and that she's excited to see what I've done next. I'm lucky that way-she keeps me going and helps see things from a different point of view.
I'm at a point now where it's actually getting exciting and it's starting to take shape, so it's coming together and I actually am wanting to do more and more. Problem is time-work gets in the way so I only get a couple hours each day a few days a week at most. Hopefully by April I'll be done with it, ready to paint.
Anyway, while this post is horribly long winded, I hope you at least found something of value to help decide one way or another on whether you should tackle the project or not. In the end, it will be very rewarding, and a great addition to your rig.
Best of Luck with whatever you decide,