"Greybeard" wrote in message
...
My chuckle, it would be interesting to know by what method they
determined that it was "cheap carbon steel" rather than 41XX or
anything else. The only way to know is laboratory analysis, and
there's only a .0001% chance that anyone has done that before posting
that they got something else. The chances of anyone being able to
tell from "the way it works" are zero, other bull**** explanations
stand for nothing. 4130,4140, 4150, and 1045 all work about the same
until they're hardened, then the differences show up, but you're not
going to do much with them after they're hardened. There are three
things you can tell from "the way it works",

"It's hard"

"It's tough"

"It's soft".

Period.

Greybeard

Hello, nobody at nowhere.

We'll take a sample of it and have it tested at our local technical college,
just to be sure. If the plate has chromium or molybdenum in it we'll find
out with absolute certainty. If they can't do a spectrophotometry test,
we'll find somebody who can. I'll publish the results here. You can place
your bets now.

I have taken 4130 tube and heated it red hot then quenched it in cold water.
It is then brittle, but mild steel will remain soft enough to bend. That's
why when you weld 4130, you have to normalize the welds by heating them
cherry red, then allowing them to cool gradually at room temperature and no
drafts. You, being the nobody at nowhere of authority, correct me if I'm
wrong here.

BTW, how many steel tube and rag aircraft have you built?

The purchaser called Spruce to warn them and got an admission from Spruce
that they had substituted mild steel because 4130 was not available and that
they could never be sure, with the new supplier they had.

That was after the purchaser had tested the purchased steel against the same
thickness 4130 by pulling a sample of it with some hydraulic equipment and a
calibrated gauge he uses to do destructive testing. He said the bolt holes
began to elongate at 60% of the pull necessary to elongate the bolt hole on
the known sample of 4130, indicating that the unknown sample was NOT 4130.
That's proof enough for him and anybody else with good sense.

Nobody, you can draw whatever conclusion you wish, but here in our chapter
we have drawn a conclusion based on sound evidence from a respected aircraft
builder and airframe and powerplant mechanic. Since the purchaser bought
the steel plate to be 4130 for wing attach fittings on a cantilever wing,
any knowledgeable people who read this could understand why he wrote Spruce
a letter and told them that substituting mild steel for 4130 (which is
exactly what they did) is dangerous.

Naturally he never got an answer. Naturally he won't be using that steel
plate for wing attach fittings. Naturally, as he just said over the phone
awhile ago, he won't be buying anything else from Aircraft Spruce. And
naturally, unscrupulous people who pollute the aircraft builder's market and
their toadies won't have much of anything reasonable to say.

As I said before, now having had yet another sour experience with Aircraft
Spruce, buyer beware!