Roll Cage Construction.

[Risking]

Thats something I was contemplating is a time log.

It took two guys 5 hours today to totally gut the car and have it ready for caging. That includes stripping the sound material from the floor but not fully cleaning it.

I can give a good time estimate, but Jay and myself work very well together and have done heaps of cages in the past so were pretty efficient. Ill do my best to give an estimate of how long it would take though.

With a weld in the majority of the time is in the fitting.

A bolt in is very simple and takes no more than a few hours once its painted.

[Risking]

Okay today there was a lot of work happeneing.

We got started by trial fitting the main hoop

It fits pretty well as id expect from Peter really.

So moving along the next thing we do is to knotch out the front legs and get them set up and tacked into position.

Raise the hoop up through its holes and use scissor jacks to level it and hold it roughly in place.

Make two more holes from the front legs to drop down into. We put them where ever we want and then cut the leg to length.

This is the knotcher we are currently using, its from a company called speedwerx and is brilliant.

Some careful planning is required to cut to length and get the angle of the knotch correct. Get it right and you will end up with a joint like this and a leg looking something like the next photo.

The next thing we do to add some strength to the leg joints while raising and lower the cage is to add the supports and get everything square. Nothing is welded at this stage only tacked well into position

While in this position we also knotch and fit the windscreen bar into position. Didnt get photos though.

Nest thing is to drop the whole cage down through the floor, Like this....

While the cage is down now is the time to fit up the roof bars. We could do a full X but rather a roof V. Have always done it this way and it provides strength to the center of the screen bar that a X does not.

Knotched fitted and tacked then raised back up it will look like this...

Lowered back down after checking clearance we now add in the windscreen supports and check the cage is square again.

The whole upper section is now TIG'ed in position and constantly checking the cage is staying square and level. Alot of work is required to get the thing to this stage, two guys and about 4 hours work.

Here is a perfect example of why I TIG weld my cages, The joints need to be near perfect and you get results like this...

Okay so the upper is now welded and we can lift the whole lot back up and weld the lower sections. Again alot of time is spent welding the joints and making sure everything is presentable and notched well.

Welded up and raised this is what you will be left with

So thats today's effort. Its taken alot of work and time but so far the results are good.

John is wrapped with what ive showed him so far which is the most important thing.

If there are questions about the way we have done things just ask. It may be different to the way others do it but this is the method that works for me and it allows me to fully weld every joint unlike some cages I see which have no welds around the difficult areas.

Some lateral thinking and there is no excuse for un-welded areas.

During the week ill be doing the bases and the rear section of the cage as well as the new dash support bar and begining the side intrusion bars and drop bar.

[Gts-t]

That is really good to see brad, im so jealous its not my car copping this treatment from you!

[Risking]

Thanks mick.

Its not easy to get a cage done by me. Usually we're stupidly busy building our own cars but ive kinda put mine to the side (its next to this 180) to do this job for John which is also allowing me to do this thread.

The more knowledge people have of the process and ammount of work required the better off the market in general will be.

I see so many cages not welded right or not knotched properly. Im hoping people can approach cage builders with a bit more knowledge and the right questions to make sure they are getting the kind of job they want.

[Gts-t]

Yeah i would say i live too far away to even have that pipe dream anyway, i think your spot on with what you doing though. This is definitely giving me alot more insight, i know anything with cars takes about 5 times longer than you would expect too. Looking forward to more information and photos as this progresses.

Just one question from a noob, is there a lack of triangulation where i have circuled in this photor or is it of no consequence?

[Risking]

That photo is showing a funny angle. Those two bars almost run parrallel to each other and meet at the main hoop. In between those two bars but on the other side of the hoop is where the rear legs will be welded too.

[unique1]

From the first post it seems you are not tieing in the front strut towers. But lets say u were going to, then at what stage would u do them? once the interior barwork was all fitted and done and then add on the strut tower bars through the firewall? or would u do it differently?

great write up too, im getting stuck back into mine this weekend coming as the 3 phase power will finally be hooked up at home to use the tig. Mine came with instructions a fair bit different to the way you have done it, but i understand its upto personal experience and choice which way you go about it.

My instructions say to do the holes in the floor for the hoop, then the hoop, then front legs, then one of the intrusion bars on each side and half of the other x bar, then remove the front leg from the car with baseplate attatched and weld the lot on the bench out of the car so access to the front leg pipework is easier. Then tack it back in onto hoop and do the windscreen bar, and roof barwork and then drop the rear of the hoop to weld up all the roof stuff. put it back up and tack back onto hoop baseplates, finish other half of intrusion bars and then do the rear backstays. Im still wondering how on earth to access the top of the rear backstays as i cant drop the cage to get to them, and im mounting them on top of the strut towers too which means no room to drop them at all.

I know im jumping ahead abit but how do u plan on doing the backstays? and how do u access the top part of them on the hoop?

[Risking]

We were discussion fire wall penetration tonight over the phone and yes it will now be a triple bar through the fire wall to the shock tower, Twin bars are difficult but triple is kinda hard to get symetrical and allow the booster to be used so yeah will see how it goes.

Firewall bars are not done untill the legs and hoop are based and done.

Im familiar with that method but it does not work well for me. I like to have the legs in and done before the intrusions as it makes getting into the car to do the cross work so much easier. Also the base plates are better made inside the car and welded up before the legs are attatched.

You will see in the next few days why I do it this way and the rear legs are one VERY big reason I dont follow that method.

The way I do it will allow the cage to be moved down AND forward which drops the legs down off the edge of the shock tower and hence away from the roof by about 3 inches.

Its simple to do and over the next few days Ill have good photos and show the method for you.

[evil_weevil]

Looks like its going to be a good work of art Brad, top stuff!!

[BOZ22N]

Very nice Brad and Jay.

You can tell when people take pride in there work.

My understanding of a roll cage is that it is there to if you have an accident and the cage is only going to be as good as its weakest link, and this project looks superb. It will be good for everyone purchasing a cage to know what to expect when they get one fitted.

Great work.

[Risking]

Thanks guys,

We do take alot of pride in the job, this car in particular will obviously have some very critical eyes pass over it during the course of its life.

Jay and I have done so many of these now, but its odd going back to a floor pan car when we've been playing space frames for a few months now.

Glad people are learning what it takes to build one properly. The cost of doing such a cage can be very high particularly when its fully TIG welded. With some luck this log will open a few eyes to whats involved.

You should be getting a good idea what your car is in for when you get it caged Ryan.

Make sure you ask the cage builder all the right questions before leaving the car with them.

Hahaha in one of those photos you can actually see my old man cruising around his back yard in the bobcat.

We are using his garage for this project as Im outta space at my place currently with GTR's all over the place.

Edited August 9, 2009 by Risking

[underground32]

being entirely hopless with any form of Metal fabrication I am in absolute awe of anybody that can do this sort of thing. All the best with the rest of the build

[Risking]

Tonight I got the drivers side intrusion bar cut and tacked into place and begun the rear legs. The Shock towers have now been paint stripped and the plates tack welded into position as well.

Im trying something a little different with the rear legs on this car and I think it will be much easier and quicker to do than previous cages but give the exact same results if not better.

Ill put up photos and a write up of the intrusion bar procedure tomorrow as im buggered now and not in the mood.

[warps]

Great write-up Risking. This is especially interesting as I am contemplating a 180SX build for my next gravel rally car, and will be putting in the most comprehensive cage I can fit in there. Rather spend $$ on a good cage than making it go fast. Good cage and a set of MCA's will probably do me (with the necessary seats, harnesses, instrumentation etc). Engine and driveline will probably wait till I feel the cars holding me back, rather than the other way around.

Just a heads up on notching - those notchers are a good bit of kit, but we;ve never bothered with them in the past. We find that cutting the pipe ends with a drop saw gives the same effect when done correctly, with the added benefit of bevelled joints that don't need prepping. yes, I'm anal and like to prep all my weld joints. Probably not really needed, but I find it gives a good result and makes more sense to me.

Also agree with cutting the holes in the floor. By the time you re-plate them, and then box the mounts you haven't given anything away in strength. I've seen too many dodgy cages with only half welded joints (which, BTW are often still plenty strong, but again I prefer to make it as strong as possible).

Will be watching this one with interest. Good for tips on what to look for when I get around to building my next car.

[phunky_monkey]

This is a top thread, thanks for sharing Brad. Bit jealous of the cage! You're doing a great job, can't wait to see the finished thing.

[9krpm]

Beautiful welding and cage work mate.

Thanks for the thread it has been a good read

*Waiting in anticipation to see how you fabbed the side intrusion bar. It seems that everyone does this differently*

[Risking]

Okay back onto the cage.

Ive had a few other things to deal with but this has still be progressing.

The intrusion bars were cut and knotched then the intersections welded and the ends firstly tacked to the legs and the main hoop.

After the bars were tacked and welded in place the time has come to trim off the main hoop and front legs to the desired length. Seen in this photo is the area im talking about.

The bases will latter on be boxed into the main sills of the car at the right heights.

By cutting these off at the right height it allows the entire cage to be lowered and moved forwards and backwards far enough to fully weld the edges of the bars were they meet the legs and hoop.

As you can see with the 180sx it was possible to get the legs right out of the door jam and welded them exactly that same as the other joints

While the cage is mobile like this Ill be making the door opening drop bars which also need to be welded with the cage moved backwards.

Tomorrow ill get into the drop bars and the base plates, the rear legs have also been dumby cut and knotched but more on those once the bases are made and they are ready to be crossed up and fitted properly.

[Duncan]

dirt rally posts moved over here: http://www.skylinesaustralia.com/forums/Gr...ns-t284416.html

[Risking]

well today we go the drop bars in the front door openings done. These can be difficult to get knotched up but after doing alot of them they come out well.

One thing we noticed with the S chassis is that the a pillars taper into the center of the car alot more than the R chassis. Making the drop bars a little more intrusive than a skyline but still livable and well worth the effort.

We also got the cage set on its base plates very roughly and managed to get the rear legs and cross section made up and welded in.

More on the base plates tomorrow when we box them in properly and set the cage in position.

[Roy]

Any particular reason why you have done the side intrustion as the X rather then the )( bent two sections gusseted together. Looking at the UK and Aus tin tops and many of the current rally cars they tend to be going for the bent sections rather then the 3 pieces welded in X together