Contemplating the graph that shows 1095 has a peak on torsional impact
when tempered to 325 F and that drops off at tempertures from there to
600 F or more (don't have the graph in front of me), I got to wondering
about that weak area that would exist between the spine and edge when
differentially tempering a knife and if perhaps it would make sense when
tempering to 325 F to leave the whole of the knife full hard?
Also would this make a differential quench preferable to differential
temper and if so does it make a difference between edge quenching and
Sitting here looking at this, I feel these questions aren't fully
formed. Hopefully y'all understand what I'm getting at.
That peak is a "machine measured strength" just like it's a machine
measured fact that the "stiffness" of mild steel and heat treated
4140 (like a wrench) are the same only the yield strengths are
To your hand, the "all hard" knife will "feel" weak. :/
Even tho it isn't.
Making knives that way is exactly what I do, because all I really
care about is edge holding. Since I give them away, I don't have
a problem with anybody complaining at me neither. ;)
There are two-edges at the back of a knife if you grind it nice and
square and leave them "sharp". Peeling carrots is one use another
is reeming a fresh cut piece of pipe another is sharpening a factory
The drastic dip in the graph is also due to the "1 hour draw".
A quick (and dirty;) blacksmith type draw produces different
results. Danggit, I've never found strength tests covering
"blacksmith type" "quick tempering" methods. :/
Know of any? Anyone? :)
Either way this is my newest-latest interest so thanks for the cool
post. :) Now if I could only find some resources that covered our
"I got to wondering about that weak area that would exist between
the spine and edge when differentially tempering a knife...
There's got to be a hundred (valid?) methods to make a "tough knife"
with a 66hrc edge... many of which have been, and still are I guess,
thought of as "secret".
I'd like to get all of them out in the open and discuss the pros and
cons of them. Someday I'd like to make a "tough knife" with a 66hrc
edge that has a "spring" back.
Alvin in AZ
ps- I re-arched my leak springs on my '75 F150 using a 10# and a
16# sledge hammers and now need to un-do some of it especially
on the passenger side... springs can be tough as nails ;)
pps- they didn't "settle" at all!
It does feel different than any knife I've ever used. The cutting
action is so effortless when the grind is right tho I really like it.
I'm looking to one day sell mine and want to offer the best I can and be
able to explain why I do what I do.
I find sharp corners cut into my thumb when I put it on the spine.
Therefore i tend to ease those edges. I suppose I can see the
advantage. I like to check grind bevels by cutting carrots. A good
grind will slice the carrot. A lesser quality grind (but by no means
poor) will split the carrot.
sounds like an opportunity for some destructive testing. Now if only I
could afford to destructivly test a few dozen blades.
My biggest complaint with "trade secrets" is that the knowlegde is only
1/2 of the equation. The rest is skill that can only be aquired by
years of experience. That developed skill should be enough to let all
secrets out in the open so the best methods can be determined and used.
ps- I sold a knife the other day.
pps- am working on getting my newest on my site
Ah, yes, that's the tiny little divide between learning what to do and
learning _how_ to do it that can take a lifetime to cross.
Smithing is easy: You just grab a piece of iron, heat it up, and beat it
with a hammer until it looks like what you want it to look like.
That covers the what to do. :)
More horse poop? :/ The pile that sometimes occupies the drivers
seat ain't enough? :/
Alvin in AZ
ps- the spring-packs are out again and look to be exactly the
same... so I'm gonna go for a little different this time ;)