Always lots of talk on here re: Roll bars which I find interesting as I am considering building a full cage for my MK. While it looks fairly straight forward, one question, how do you bend the tubes?
With a about a grands worth of tube bender.
Oh well, I'll give that idea miss then.
Mandrel tube bender, NOT with a hydraulic pipe bender
Draw up what you want, contact tubebender on eBay and take delivery of a nice flat pack ready for you to assemble.
You will struggle to find someone local who will compete on price and he carries the correct CDS tube.
What are you going to use the rollcage for proper FIA 750MC racing, track day use or some thing to put a roof box on for road use? I make NASA
Autograss roll cages from 32x2.5 and 42.4x2.5mm ERW and they hit telegraph poles at 60-80mph.
It's not about the machine you use it's about using the correct type of TUBE former not a pipe former it just depends how pretty you want it
look and how much you want to spend. I use a record plumbers former and one of the 12 ton £60 benders with plenty of grease and knowing where to put
the pins.
quote:
Originally posted by mark chandler
Draw up what you want, contact tubebender on eBay and take delivery of a nice flat pack ready for you to assemble.
You will struggle to find someone local who will compete on price and he carries the correct CDS tube.
£100 hydraulic bender from eBay will put a curve into scaffold pole (thick wall tube), use it on thin wall CDS and you end up with the internal bend
crimped up which will fail MSA specs.
That ERW bend looks like it's started to crimp on the inside.
To bend thin wall CDS you need a bender that draws the bend, not one that just pushes a former into it.
There is a big weight penalty using thicker tube than is required, a flat pack cage in CDS should not be more than £150 really.
It's also quite hard to bend in the same plane so the finished hoop lays perfectly flat, muck it up and your tube is scrap.
nb/ I have a 12 ton bender as I used to make cages when racing landrovers with thick walled tube where weight was not so critical, for my little car I
pay the money.
[Edited on 17/12/15 by mark chandler]
quote:
Originally posted by mark chandler
Draw up what you want, contact tubebender on eBay and take delivery of a nice flat pack ready for you to assemble.
You will struggle to find someone local who will compete on price and he carries the correct CDS tube.
On a related note once you have received your flat pack how could you go about putting accurate fish nouth cuts on the ends?
I have read about CADing up paper templates but to do this you would need to map your car dimensions very accurately.
I cut mine with a 2" hole saw then trimmed, hold the pipe against the work to get the angle of the pilot hole.
You can also wrap a piece of card around the pipe, offer into position and chop this with sissors until perfect then slide down, mark the pipe with
the card template and use the angry grinder.
Hole saw needs a firm grip on the drill as it will Buck!
Make sure you can access each part with the welder, easy to box yourself in.
It's one of those things you dread doing, but once into it becomes easy 
[Edited on 17/12/15 by mark chandler]
If doing a roll hoop you certainly do not want to get sections and weld them in you may be able to hide the fact there are welded, but will you have
the strength.
I built a bender for 1 3/4inch CDS tube and it worked out OK
http://www.tamarisktechnicals.com/pages/tubebend.html
and there are hydraulic benders on Ebay for eBay Item less then £300
Adrian
[Edited on 18-12-15 by AdrianH]
another vote for tom at tube bender, he will do the notches as well if you tell him