Thread: Rollcage bending

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I am inspired by the fact what I am about to post I will sleep well knowing I am trying my best to protect you.BUY A KIT.It ant worth pinching penny's when it comes to your safety weather or not your amongst us or view the world from a wheel chair for the rest of your life.This is serious stuff,no joke!!.

I think you will find only Moly cages have to be TIG welded, Mild steel can be either MIG or TIG.

Originally Posted by sunsetdart

If this cage is for drag racing..............it MUST be TIG welded!!!!...........rules state no more MIG welded roll bars or cages.

Originally Posted by roadster32

I think you will find only Moly cages have to be TIG welded, Mild steel can be either MIG or TIG.

Exactly...
From the NHRA rule book

Section 20 - General Regulations 20.19
4:11 ROLL CAGE
All cage structures must be designed in an attempt to protect the
driver from any angle, 360 degrees. "All 4130 chromoly tube welding
must be done by approved TIG heliarc process; mild steel tube
welding must be approved MIG wire feed or TIG heliarc process.
Welding must be free of slag and porosity. Any grinding of welds
prohibited." Plating of chassis prohibited for all cars manufactured
after Jan. 1, 2003, unless otherwise noted in Class Requirements;
painting permitted. Additionally, roll cage must be padded anywhere
the driver’s helmet may contact it while in the driving position.

There is a multiplying wt factor of the vehicles wt as it gains speed that the roll-bar/cage must endure in a rollover.I used to have the formula for that,but at the moment I can't find it.That is why winkle free bents,bracing and good tight fish mouth seam welding is critical.The weld should fuse the metal together and not be used as a glue.Out riggers are ok for mounting points as long as they fall within the expected spec a roll-bar/cage would put on them in a rollover.I am not a big fan of floor pan plates for a mounting point because I have seen them deflect or punch threw.I prefer to see direct mounting points to the main frame or out riggers.Triangle bracing to spread the load and X bracing to tie it together are also very important.Again all tight seam welding is a must.