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'Precision' U brackets
johnH20 - 20/5/19 at 04:28 PM

I need to make some close fitting U shaped brackets to fit around a harness bar ( 42 mm diam ) to fix my harness which has bolt on fixings. ( Before anyone suggests it the webbing is too short to cut off the fixings and do a wrap around installation - that was my first thought! ) Material I intend to use is 3 x 25 mm. My previous attempts to make this kind of bracket have not been entirely successful. Bending around a former of the appropriate OD results in the bracket being over size due to spring back. Subsequent attempts to tighten the radius in a vice results in distortion of the form. It sounds very simple but I am obviously missing a trick. Any advice welcome. TIA.

[Edited on 20/5/19 by johnH20]


coyoteboy - 20/5/19 at 06:48 PM

Use a springback calculator?

https://eicac.co.uk/Springback-Calculator

Or get some CNCd for bling status.


02GF74 - 20/5/19 at 07:20 PM

42mm exhaust clamp work?

Tack weld it to former then start bending it, adding more tack welds to hold it in place as you hammer it into shape.


gremlin1234 - 20/5/19 at 07:35 PM

in simple terms, just wrap it round a tighter former, then open it out, rather than trying to squish it.


coyoteboy - 20/5/19 at 07:51 PM

Or just heat it to hell and try to take the spring out of it.


907 - 21/5/19 at 12:26 PM

Bend it round a former that's smaller than you require and it will hopefully spring out to the required size.

You already know the former you first used and the size it sprang out to so its safe to assume that a similar amount of spring
deducted from the finished size you require will give the size of the former needed.


With all metal forming its better to slightly over bend then ease it open to relieve the stress, and then it stays in position.



HTH
Paul G