Bending pipe 90 degrees (Accurately)

31 Oct 2004
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United Kingdom
Hi guys,

Can anyone please help! When bending pipe i.e 15mm copper pipe there is a formula for getting an accurate bend at say 90 degrees. Is the formula 2 x diameter or is it 4 x diameter. I being told different things and I'm becoming increasingly confused.

Thanks in advance

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Think that only refers to the radius of the bend not the angle.

I find the best way to bend is to bend pipe until it looks 90 and then check with a roofing square centre to centre.
You can then mark your former permanently :)
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or fit one of these

push fit are even easier
a door jam is a good place to check your 90' bends.
(as long as the house is not subsiding)
Hi guys & thanks again,

I was refering to bending a 15m pipe with a machine pipe bender with guide. One guy has told me that to create a 90 degree bend you double the radius and add it onto the measurement. The other has told me that you x the diameter by 4 and this gives you the bend. I can't really make it clearer as this is all I know.

Hope it helps!!

are you referring to bend allowance?
i get a shed load of pipe, and do it "empirically" :eek:
when im sober ill tell you, but i get the impression this is a wind up :LOL:
measure the end of the pipe to the centre of the bend then 1/2 diameter this gives you your bending mark
which you then line up with the other end of your former :LOL:

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