locoboy
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| posted on 21/7/07 at 12:31 PM |
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bending 5mm flat bar
I have just tried to bend my front wing stays that are made of 5mm flat bar.
Put it in the vice and heated it till it was cherry red.
Then bent it by hand whilst hammering the bend to help keep it tight.
Once cooled i noticed it had cracked on the outside of the bend and i have it a wiggle and i heard another 'crack' and the bend has as
good as cracked through now.
How are you 'supposed' to do this in order not to crack it?
I have oly sone one wing stay so i need advice before i start on the other one!
Cheers
ATB
Locoboy
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tks
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| posted on 21/7/07 at 12:34 PM |
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what i did was giveing it a deep cut with the angle grinder. (cut disc 1mm) then i just flipped it over and i tested the angles.
when i thought it was good then i just filled the cut up with weld. if i was you i would just do the second the same.
and then take it to a TIG welder.
He then can genereate a nice welding pool over/on the cracks. then its rock solid again.
Tks
The above comments are always meant to be from the above persons perspective.
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Peteff
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| posted on 21/7/07 at 12:38 PM |
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Bend it to the angle you want and weld the crack up, it should last ages.
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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JoelP
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| posted on 21/7/07 at 12:40 PM |
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i tend to just hammer it cold in a vice. 
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worX
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| posted on 21/7/07 at 12:45 PM |
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I'd do it cold aswell...
Steve
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Hellfire
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| posted on 21/7/07 at 01:32 PM |
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Depends how red your cherry's are...
I tend to heat it up until bright red (tomato red) then bend it. The steel should not have cracked if you did this correctly.
Heating to bright red will enable plastic deformation, but as stated they can be bent cold. Sounds like you may have a dodgy steel or left it to cool
to much whilst braying it.
Steel doesn't typically like to be bent to too tight a corner either... any chance of seeing pictures. Occasioannly you get stress marks but not
cracks...
Steve
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Humbug
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| posted on 21/7/07 at 01:45 PM |
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I did mine cold in a vice... bloody hard work, too!
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BenB
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| posted on 21/7/07 at 02:01 PM |
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Yup. Cold in a vice. No cracking......
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locoboy
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| posted on 21/7/07 at 02:13 PM |
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well i cut the cracks out with the grinder and filled it with weld so fingers crossed!
Cheers
Colin
ATB
Locoboy
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locoboy
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| posted on 21/7/07 at 03:50 PM |
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Well on the second one i sliced tha back of it and heated it up more than before...................
expecting a nice easy tight bend it bloody snapped off!
So i had to weld it back on in the end anyway!
not having a good day at it today.
Think i may have fcuked up my front cycle wings to boot. 
ATB
Locoboy
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David Jenkins
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| posted on 21/7/07 at 05:43 PM |
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I took mine up to "as hot as I could manage with a torch in a makeshift hearth" - past yellow, heading for white. Bent like putty (hardly
any need for a hammer) and no signs of cracking.
Blacksmiths would regard cherry red as "too cool to hammer, time to put it back in the hearth.".
Also - what kind of steel are you trying to bend? The BDMS (bright drawn mild steel - the shiny stuff) is likely to crack when bent. The hot-rolled
"black" steel (with the scale) is far more malleable.
[Edited on 21/7/07 by David Jenkins]
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