want2race
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| posted on 19/5/05 at 11:29 PM |
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Any advice on bending roll cage tubing
Im looking to bend 1.680 DOM steel.
I have a pipe bender but the die is correctly sized. Any advice before I screw up $300 in tubing?
Thanks
`Jonathan
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kb58
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| posted on 20/5/05 at 12:04 AM |
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Ask at the car fab shops in your area, even places that make off-road type cars. Since you're in GA, find a stock car fab shop. I had mine
bent at a place that makes nothing but roll-cages, AutoPower in San Diego. If you fax them a drawing they can make it and ship it to you. They do it
all the time.
It was about the only part of my car that I didn't even want to attempt on my own...
[Edited on 5/20/05 by kb58]
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
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want2race
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| posted on 20/5/05 at 01:40 AM |
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There are NO fab shops in my area!
I spent the day today trying to find a place with a ball joint reamer FOR AMERICAN CARS!~ Its damn standard for 99% of american cars.. Nobody had it..
and I asked about cages and Nobody will just do bends for me.. They want the entire cage.. AKA $1200 for something I can do for $120
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jambojeef
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| posted on 20/5/05 at 08:11 AM |
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Bending 50mm CDS is hard!
You'l need a big bender
Geoff
 
Rescued attachment bender.jpg
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Peteff
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| posted on 20/5/05 at 09:53 AM |
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Geoff, you need a former with a better radius
Try bending it round the back of your neck instead of over your knee  .
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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JonBowden
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| posted on 20/5/05 at 10:10 AM |
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Just a thought, if you could find an off the shelf roll bar with the right width and similar height, you might be able to modify it for a seven.
Jon
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Avoneer
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| posted on 20/5/05 at 11:05 AM |
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Jambojeef - is that a pic of the big bender?
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
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jambojeef
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| posted on 20/5/05 at 11:31 AM |
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Big Bender
Liam would you like to comment?!
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NS Dev
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| posted on 20/5/05 at 11:58 AM |
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I used to have that problem before I realised that if you anneal the tube to some extent first, it works much better.
heat it to dull red for a length of around 10 inches in the area of the bend, then bend it while it's still pretty hot. Bends a treat then.
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timf
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| posted on 20/5/05 at 12:44 PM |
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quote:
Originally posted by NS Dev
I used to have that problem before I realised that if you anneal the tube to some extent first, it works much better.
heat it to dull red for a length of around 10 inches in the area of the bend, then bend it while it's still pretty hot. Bends a treat then.
but if you want one thats msa approved then it has to be cold worked.
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The Shootist
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 posted on 20/5/05 at 02:02 PM |
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Have you considered a muffler shop?
The newer stainless exhaust tube is pretty tough. A good muffler shop might be able to help.
For fabrication look under Erectors... online or in the phone book.
Industrial electricians also bend heavy wall conduit on occasion.
Try calling a few auto custom shops. Tuners etc. Or spend Friday/Staurday night at the local dirt track.
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MikeR
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| posted on 20/5/05 at 06:08 PM |
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quote:
Originally posted by timf
quote:
Originally posted by NS Dev
I used to have that problem before I realised that if you anneal the tube to some extent first, it works much better.
heat it to dull red for a length of around 10 inches in the area of the bend, then bend it while it's still pretty hot. Bends a treat then.
but if you want one thats msa approved then it has to be cold worked.
Ahh but before Nat says anything the bending process work hardens the steel and its got to be better than nothing.
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Liam
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| posted on 20/5/05 at 09:29 PM |
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quote:
Originally posted by Avoneer
Jambojeef - is that a pic of the big bender?
Oi!!!
The bender taking the photo is significantly larger!!
Was quite upset when this happened. Used a 12 ton hydraulic bender with the correct former and this happened??? I think the thickness may have been
too much (3mm) and it just wouldn't stretch over the top. Dunno.
Amazingly the guy at newcastle metal supermarket took back the unbent piece of tube and I got most of me money back!! I'll leave it to the pros
next time.
Liam
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Cita
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| posted on 21/5/05 at 06:49 AM |
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I dunno if it would pass SVA but i made the roll bar of my single seater with 50mm,3mm wall ellbows welded together.They cost close to nothing and you
only need a flat surface for layout.
With the choice of 90°-45° etc.. you can pretty much make any shape you want.
Cheers Cita
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jack trolley
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 posted on 21/5/05 at 03:53 PM |
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If you used a 12 ton hydraulic bender like the Machine Mart one,
it's a PIPE bender. The 2" die refers to the internal diameter.
The external diameter is 2 3/8" - approx. 5mm wall thickness.
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NS Dev
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| posted on 23/5/05 at 11:02 AM |
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quote:
Originally posted by timf
quote:
Originally posted by NS Dev
I used to have that problem before I realised that if you anneal the tube to some extent first, it works much better.
heat it to dull red for a length of around 10 inches in the area of the bend, then bend it while it's still pretty hot. Bends a treat then.
but if you want one thats msa approved then it has to be cold worked.
As Mike R said further up, you will work harden it again when you bend it, plus.........how will they know!!!!???
You only really have the one choice, as the only other option is to buy ready annealed CDS, which won't pass the strength requirements of the
MSA spec anyway! If you try and bend un-annealed CDS in any bender, it will either crack or kink.
I have bent 45mm x 2.5mm and 45mm x 3mm CDS tube in my 12 tonne bender with the correct 45mm TUBE die (not pipe die) and locally annealing it.
If you are worried abut strength, use bigger tube. Don't worry about MSA regs, the tube will meet the tensile requirements after bending, and
there is no way of knowing that it was locally annealed unless you section the tube and metallurgically test it, and then it ain't much good for
a cage!
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Liam
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| posted on 23/5/05 at 10:34 PM |
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quote:
If you used a 12 ton hydraulic bender like the Machine Mart one,
it's a PIPE bender. The 2" die refers to the internal diameter.
The external diameter is 2 3/8" - approx. 5mm wall thickness.
Aaaaaaaaaaahhhhhhhhhh
quote:
If you try and bend un-annealed CDS in any bender, it will either crack or kink.
Aaaaaaaahhhhhhh
Arse!
[Edited on 23/5/05 by Liam]
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jambojeef
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| posted on 24/5/05 at 03:03 PM |
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Well that explains something anyway!
Geoff
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timf
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| posted on 26/5/05 at 07:23 AM |
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quote:
Originally posted by NS Dev
If you try and bend un-annealed CDS in any bender, it will either crack or kink.
 
bar1
cds 1.75" tubing bent without annealing
no kinks or cracks.
[Edited on 26/5/05 by timf]
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NS Dev
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| posted on 26/5/05 at 07:34 AM |
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What was the exact steel spec?
I said un-annealed, that was quite probably annealed tube (not by you, by the people that made it!)
What was the code for the tube, should be CFS3 followed by a pair of letters, BK is cold finished, as finished (will crack/kink) BKW is cold finished
soft condition, (will still probably crack or kink) GBK or GZF are annealed, will bend fine.
NBK or NZF are normalised, and to be honest I have still kinked this in a proper bender.
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