spread using the sheldon method. No worries on alignment, I took all the necessary steps there.

As of 11:15 pm it hasn't gone back again. (approximately 3 hours after the wheel was removed).

Assuming it stays this time around, I have apparently bent it past the point at which it would be inclined to go back.

One though I've had is the butterfly brake bridge and stabilizer at the bottom or the rear triangle (also a butterfly shape) may have contributed a bit to my troubles in bending it before. But then... they can't be doing much more than the standard bar type ones. People cold set those all the time. Soooo.... I have no clue what happened the first time around.

Seriously, if your steel alloy frame does not behave in accordance with my previous post then you have something truly newsworthy. In other words, if the shape is changing with time at room temperature with no external stress applied then there is a phenomenon at work that is not explained by the known models of steel metallurgy.

The elastic range of steel is what makes it unlike any other commonly-used metal. If steel didn't spring back after being flexed, it wouldn't be steel, and every steel bicycle frame/fork, suspension/cantilever bridge and super skyscraper on the planet would snap and come crashing down. Google "tacoma narrows" to witness how far steel can flex before fatigue finally occurs.
The learned art of the cold-set is to deflect and approach the yield point carefully, while not exceeding the yield-point-deflection to obtain the final position desired upon spring-back; not a novice procedure. The smooth bend of a fork's rake is typically a cold-set process, isn't it?

a cold set has to exceed the yield stress. The only care you need to take is not going too far. There is no subtlety to the process other than that. The smooth bend of a fork is a result of a smooth form that the blade bent over, nothing more. My fork blade bending rig has a 6' bar on it so I don't have to work too hard. You just pull on that until you get the rake you want plus some springback

Thanks for the definitive knowledge from someone who is obviously an experienced professional, unterhausen.
I don't pretend to have anything that approches the authoritative knowledge of a pro, and readily confess my own knowledge about frame/forkbuilding could frankly and practically be limited to what I've read in a book.
My late father was a top-notch machinist, trained machine-tool-bulder (ever hear of Walrich?), and very sucessful tool-and-die man for most of his life, so I continue to be fascinated with any precision metalwork, especialy the kind that sucessfully employs skills only achieved over decades of patient experience.

Maybe you just forgot to measure twice..... it will only spring back to the original spacing if you never went past the rear triangle's tubes yeild point, and springing back would be pretty much instant, if it did spring back......unless you have a C&Ver ghost messing around with you........

Chombi