O.P. >"I'm sorry, I know I'm totally being a grammar dick but can you please answer in sentences, rather than fragments, I totally can't understand a thing you're saying, and it's not like I'm clueless about bicycle anatomy. and for the record the bb is fine, I switched out the spindle and repacked the bearings a couple of weeks ago, it's all crank spider. I guess I'd be worried about catastrophic failure assosiated with bending it back."
? Use the search function to locate threads about metallurgy.
Crystal structure :The regular, repeating pattern of atoms in a metal. Crystal structures develop as a metal solidifies.
Grain structure: The relationship between the small, individual crystals in a metal or alloy.
Tensile strength The ability of a metal to resist forces that attempt to pull apart or stretch it.
Ductility A metal's ability to be drawn, stretched, or formed without breaking.
"When a stress is applied to the atomic lattice it will "slip" along certain geometrical planes that vary in size, number and importance, depending if the alignment is HCP, FCC or BCC. The lattice will also contain flaws (missing atoms, misaligned rows) that will travel freely through the lattice when stress is applied, which explains metal ductility. However, continual stress will rid the lattice of flaws (by pushing them to the grain boundary) to produce a more rigid/strong metal, which explains another metal property - work-hardening.
The outer electrons of metallic atoms are loosely held by the nucleus and exist in a fluid-like state shared by all the atoms of the metal. This "migration" of electrons explains the high thermal and electrical conductivity properties of metals.
Common furniture metals can be grouped into two main classifications - ferrous and non-ferrous, from the Greek word ferro, which means iron. Steel and stainless steel are typical ferrous iron alloys; aluminium is a typical non-ferrous metal."
"With steel, there is a stress level below which fatigue failures do not occur: the fatigue limit. A part loaded below the fatigue limit may eventually develop fatigue cracks, but they won't grow to the point of fracture. Therefore, a steel part (such as a crankshaft) can theoretically remain in service forever, provided it doesn't corrode or wear beyond service limits.
In sharp contrast, aluminum and other nonferrous metals have no fatigue limit. No matter how low the stress level, eventually the metal will suffer a fatigue failure if it is subjected to enough cycles. This means that aluminum parts are inherently life-limited."
http://www.avweb.com/news/maint/184271-1.html
The lattices or 'structure' of Aluminum do not have the same tensile property of steels in that they are fractured along the lattices when bent where steel being tensile can have the grain re-align without fracture.
A bent piece of ALU will be WEAKEn when bent back.
I will point to the abandonment of aluminum affixed derailer hangers in Alu frame bike design.
If bent, then bent back, they often fail.
A better fix is to remove and use a replaceable hanger.
A steel hanger affixed to the frame, bent, simply re-align. Can be done several times without it breaking.
From my limited knowledge of the star called 'earth' metallurgy.
Originally Posted by peripatetic
I second Mr. You...who are you, and WITH are you talking about? Why can't you write in even half-complete sentences? Reads like you've just come down from another star system or something.
I hereby declare this thread useless.
I declare your post moot, but not obtuse.
Is all this easier to understand? Do whatever you feel is safe.
You know what I think. Bother, lack of research skills, me again posting and I type with 2 fingers.