Tubing Radius Tolerances?

[wchowe]

Does anyone know if there are standards concerning the radius on the corners of box beams? I have a 2" square 1/4" wall beam that is coming from two different vendors with 2 different radius.



Thanks
Bill

 

[desertfox]

http://www.roymech.co.uk/Useful_Tables/Sections/SHS_hf.html

http://www.roymech.co.uk/Useful_Tables/Sections/RHS_hf.html

The BS EN number is also on the site

desertfox

 

[wchowe]

Desertfox

Good information, thank you. Do you know if this varies by manufacturer or is governed by some society? Do you know the tolerances on these number? If the tolerances are overly generous then the numbers mean little.

Thanks
Bill

 

[desertfox]

Hi

According to the Corus little blue book the external corner radius should be greater than 2* wall thickness but less than 3x.

http://tsbluebook.steel-sci.org/Support/Entry.htm

desertfox

 

[wchowe]

Good stuff, thanks!

Thanks
Bill

 

[desertfox]

your welcome

desertfox

 

[wchowe]

It looks like the steel makers have too much manufacturing tolerance allowable. If I have a typical 1.5" square tube with 1/4" wall thickness, my max permissible radius would be 0.75"? This would change the square to a round tube? Curious........

Thanks
Bill

 

[MintJulep]

If you are buying tube to a specific standard that that standard would tell you everything you want to know. For example, your sizes of interest might be covered by ASTM A501 - 07 Standard Specification for Hot-Formed Welded and Seamless Carbon Steel Structural Tubing.

If that's what you want, and that's what you are ordering, then go buy that standard.

Of course, there may be other standards that cover unspecific "2 inch square 1/4" wall tube". If your purchase order is not specific then you don't really know what you're expecting do you?

 

[MikeHalloran]

The standards are loose.
If corner radius is that important to you, use one vendor.


Mike Halloran
Pembroke Pines, FL, USA

 

[racookpe1978]

The functionality of a "2x2 sq tube steel" member is not "usually" extremely dependent on the radius of the corners.

At higher wall thicknesses, at that small a tube wall length, it's very very difficult to get good consistent bends - particularly overseas. (IE, cheap.)

So the smaller wall thicknesses will be sharper cornered, the thicker - and 1/4 is very thick comparatively - you should expect large radius. See the real spec's above.

And, for most purposes, a larger radius will carry stress better: A 2x2x1/4 tube steel member is what is used most often on trailer hitches for example. Vertical platform members. Tank legs. And on none of these will the radius be a problem, so most people ignore it.

For handrails, I like 14 gage for sharp bends at 2x2 0r 1-1/2x1/2: beyond that, even 11 gage seems to "feel" rounded.