jabs
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| posted on 2/7/08 at 01:13 PM |
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Bending seamless tube
Looking into making a roll bar for the haynes roadster and I have just had a word with my local steel stockist and he says that you cannot bend
standard seamless tube without it cracking or collapsing. He says you have to use annelled steel tube. Is he right, as anyone had problems bending
seamless tube.
The tube is 50mm with a 3mm wall
Regards John
[Edited on 2/7/08 by jabs]
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SeaBass
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| posted on 2/7/08 at 01:21 PM |
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Sounds like twaddle to me - BUT how are you going to bend tube with that kind of wall. Do you have a hydraulic mandrel bender?
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MikeCapon
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| posted on 2/7/08 at 01:26 PM |
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Depends what sort of seamless tube you have. 'As drawn' tube is very difficult to work without cracking or tearing. For this reason tube
is often annealed or normalised after drawing to make it suitable for bending etc.
On the spec of the tube you should have a suffix
BK = As drawn
NBK = Normalised
GBK = Annealed
ETA If you find you've got BK then you will just need to anneal the section you want to work.
[Edited on 2/7/08 by MikeCapon]
www.shock-factory.co.uk
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jabs
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| posted on 2/7/08 at 01:35 PM |
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quote:
Originally posted by SeaBass
BUT how are you going to bend tube with that kind of wall. Do you have a hydraulic mandrel bender?
Was considering using one of the 12 ton hydraulic benders
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DaveFJ
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| posted on 2/7/08 at 01:41 PM |
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He's talking out of his rear orrifice...
however - you do need a mandrel bender and 3mm thick CDS is tough stuff....
you need a tube bender not a pipe bender as the dies are the wrong size - but if you do a search on the site you should find loads of info regarding
this.....
Dave
"In Support of Help the Heroes" - Always
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Minicooper
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| posted on 2/7/08 at 01:45 PM |
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I use NBK seamless, bends nicely, I have also bent as drawn seamless and it was also fine although it took more effort to bend it.
As long as you don't try to bend a tight radius it seems to bend okay, you will need a proper tube bender to do it though, these 12 tonne
hydraulic pipe benders from Machine Mart and the like aren't much cop
Cheers
David
[Edited on 2/7/08 by Minicooper]
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DaveFJ
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| posted on 2/7/08 at 01:50 PM |
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quote:
Originally posted by MikeCapon
Depends what sort of seamless tube you have. 'As drawn' tube is very difficult to work without cracking or tearing. For this reason tube
is often annealed or normalised after drawing to make it suitable for bending etc.
On the spec of the tube you should have a suffix
BK = As drawn
NBK = Normalised
GBK = Annealed
ETA If you find you've got BK then you will just need to anneal the section you want to work.
[Edited on 2/7/08 by MikeCapon]
Bent my rool bar out of 1.75" x3mm wall CDS with no problems at all. Didn't anneal the tube either. just went for it. Admittedly one of
the lads off this site came over with his proper ProTools tube bender (manual not Hydraulic!) but we had njo real issues at all...
Dave
"In Support of Help the Heroes" - Always
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jabs
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| posted on 2/7/08 at 02:01 PM |
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Is this the type of bender to use
http://cgi.ebay.co.uk/NEW-12-TON-HYDRAULIC-PIPE-BENDER-UP-TO-2-DIAMETER_W0QQitemZ200233410455QQcmdZViewItem?hash=item200233410455&_trkparms=7
2%3A12%7C39%3A1%7C65%3A12&_trksid=p3286.c0.m14
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mr henderson
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| posted on 2/7/08 at 02:12 PM |
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quote:
Originally posted by jabs
Is this the type of bender to use
http://cgi.ebay.co.uk/NEW-12-TON-HYDRAULIC-PIPE-BENDER-UP-TO-2-DIAMETER_W0QQitemZ200233410455QQcmdZViewItem?hash=item200233410455&_trkparms=7
2%3A12%7C39%3A1%7C65%3A12&_trksid=p3286.c0.m14
No it isn't . For one thing it's a pipe bender and we want to bend tube, not pipe. The dies are the wrong size, and for good tube bending
you need both sides of the tube to be held in a die, just like in the Pro Tools bender shown further above. High on my shopping list.
John
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splitrivet
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| posted on 2/7/08 at 02:12 PM |
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Thats what I used for mine no problaymos but why the expense of seamless.
Cheers,
Bob
[Edited on 2/7/08 by splitrivet]
I used to be a Werewolf but I'm alright nowwoooooooooooooo
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jabs
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| posted on 2/7/08 at 02:27 PM |
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Well Chris's book says you can use seamed or seamless but from other threads thought seamless was best or is that only if you go serious motor
racing
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liam.mccaffrey
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| posted on 2/7/08 at 02:32 PM |
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my race car builder friend says you should lube larger diameter tube to prevent it from tearing in the die
Build Blog
Build Photo Album
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Agriv8
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| posted on 2/7/08 at 02:33 PM |
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alternativly fire an email of to chris at mnr Harrogate.
They have a CNC mandrel tube bender that will be able to do you a hoop to your spec.they have CDS or T45 ( both stocked ussually ).
just over the hill from the 'Golf balls' Harrogate Skipton Rd.
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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jabs
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| posted on 2/7/08 at 02:40 PM |
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I spoke to mnr, they will not make it as per book but want a signed letter stating the height and they will not supply unless they are certain it is
the correct height for the driver/seat configuration. Suppose protecting their bottom and my head in-case of an accident.
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MikeR
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| posted on 2/7/08 at 03:21 PM |
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which makes blooming good sense how ever you look at it.
In a week or two i'm going to be sitting in my car with the girlfriend holding a plank from the front of the chassis to 2" above my
helmeted head. She'll then measure a height so i know how high to make my roll bar.
I've been in car crashes and rumour has it survived - i want to keep doing so.
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Agriv8
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| posted on 2/7/08 at 03:54 PM |
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quote:
Originally posted by jabs
I spoke to mnr, they will not make it as per book but want a signed letter stating the height and they will not supply unless they are certain it is
the correct height for the driver/seat configuration. Suppose protecting their bottom and my head in-case of an accident.
That sounds like Marc.
<------- - as you can tell
personally id go for correct rather than book but the choice is yours.
MikeR that how marc did mine and is to 'blue book ' regs IIRC.
regards
Agriv8
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
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Dave Ashurst
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| posted on 2/7/08 at 05:28 PM |
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quote:
Originally posted by MikeR
which makes blooming good sense how ever you look at it.
In a week or two i'm going to be sitting in my car with the girlfriend holding a plank from the front of the chassis to 2" above my
helmeted head. She'll then measure a height so i know how high to make my roll bar.
I've been in car crashes and rumour has it survived - i want to keep doing so.
Girlfriend?
Holding a plank over your head?
In a week or two?
You and your long-distance plans.
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MikeR
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| posted on 7/7/08 at 10:00 PM |
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quote:
Originally posted by Dave Ashurst
quote:
Originally posted by MikeR
which makes blooming good sense how ever you look at it.
In a week or two i'm going to be sitting in my car with the girlfriend holding a plank from the front of the chassis to 2" above my
helmeted head. She'll then measure a height so i know how high to make my roll bar.
I've been in car crashes and rumour has it survived - i want to keep doing so.
Girlfriend?
Holding a plank over your head?
In a week or two?
You and your long-distance plans.
Scarily not that long distance - if i can get in the garage and do six 1" welds (upside down) then make one tube and weld that in (which would
mean two more 1" welds upside down ....... i'll be ready for my roll bar.
After that its weld on some tabs for the brake lines, hand brake and .... i'm ready to paint!!!
So before that i need to sort out my roll bar.
(yeah, i'm scared too - cheeky bugger )
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