Nicholson File
1.23%C .37%Mn .21%Si .16%Cr .09%Ni .04%Mo
  (extra low P & S and very low W, Ti, Al, B, Cu)
Here all this time I figured it was plain ol' 1095, turns out to be
a steel that's referred to quite a bit in most metallurgy books but
is not named, numbered or listed by AISI or SAE, only referred to as
"1.22% carbon steel". Taps, dies and reamers are also made of it.
So, a using-knife made from old files will be in good company. ;-)

6195/50100-B/W7/0170-6 (not shown, it's nothing to look at;-)
.93%C .43%Mn .24%Si .60%Cr .21%V .03%Ni .16%Cu (.20%Cu max)
  (extra low P&S and extra low .008%Al and very low W, Ti, B)
This steel is from a Western Cutlery auction in Colorado and is
supposed to have been supplied by the same outfit that supplies
Case with their "chrome-vanadium steel". Wherever it's from, whoever
came up with this one in the first place, did their homework right. :-)

Bandsaw blade ...turns out to be a Boron steel :-/
.07%C! .68%Mn .27%Si 1.15%Cr 1.05%Mo .67%Ni .17%V .04%W .002%B!
  (ok on P&S and low on Ti, Al and Cu)
.002%B is high enough to make it harden with Boron.
I was told it was L6 but it ain't, I've been using this as a "known
sample of L6" for years. :-/ Don't believe anything you hear in the
knife making business. Don't believe me either! :-/ My spark testing
made me think most newer files were no more than 1095 and been
spewing that -wrong- idea far and wide. :-/

Oldham saw blade
.68%C .64%Mn .18%Si .17%Cr
  (extra low P&S and Cu and very low on all the rest too)
A very clean straight high carbon steel. If they do call it "1069"
(which is an SAE-only listing) it's an extra clean and sound 1069.
It's not a ".70%C W1" tho, too much Mn (.10% to .40%Mn for W1).
For pattern welding this could be sweet stuff and could be welded
with 8670-modified for contrast? Both steels would be from circular
saw blades. :-)

KromEdge #1
.70%C .52%Mn .34%Si .43%Cr .11%Mo .86%Ni
  (low P&S and ok on Cu at .18%Cu and low on W, Ti, Al, B)

KromEdge #2 (the round sample)
.80%C .48%Mn .24%Si .51%Cr .11%Mo .75%Ni
  (that's all I was given about the round sample)

I talked to a couple of guys at Timken Latrobe Steel and they claim
to supply this through someone else to saw-blade producers, it has
been used in -large- quanity for years to make both the large sawmill
blades and also the small non-carbide-tipped "throw-away" saw blades.

The insider designation for it is "0186" or sometimes "8670 modified".
There is another steel that is even closer to 0186 than 8670 is, it's
ASM's tool steel class 230, type 234 (L6 is type 232).

0186 saw blade steel is not L6, 4370, 4770, 9870, 8670 or type 234.
0186 (or sometimes called 8670-modified) is on it's own. :-)

0186/8670-modified is like L6 but cheaper, but is it just as good?
Is 0186 really what's being used for knife making but being called L6?
 [I'm just a hobby knifemaker so I get to be controversial. ;-]

My first contact about 0186 was a guy that makes top quality carbide-
tipped-only sawblades for industry and they use the 0186 for the body
of the saw too. All the spark testing I've done on carbide-tipped saw
blades show them to be 4140, so I haven't ran across any of his extra
good ones yet. :-)

The composition for 0186 is supposed to be in the following ranges:

.64-.75%C .40-.60%Mn .20-.35%Si .30-.50%Cr .70-1.00%Ni .08-.15%Mo
.025%S max and .025%P max