Make sure you have a good file. Some are case hardened and will not
make a good knife.
As Ernie stated, use oil and heat it to about 125 degrees before you
quench. I use automatic transmission fluid. It will flash (lite on
fire) so be prepared for that.
On Fri, 26 Dec 2003 07:32:48 -0600 (CST), Lil_Red email@example.com
(Cockahdewalk Youbetcha) wrote:
Bob, ditch the tranny fluid. There are metalic soaps in tranny fluid to
prevent foaming, and they will contaminate the steel at quench temperature.
Same goes for motor oil and almost all the other 'automotive' petro
products, bad news for hot steel.
I have been forging knives for ten years and do my own destructive
testing to determine the quality of my knives. I have never had a
problem using tranny fluid. I have discussed this with about 2500
other knifemakers over the years on the Custom Knife Directory forum
of which there are some pretty famous and respected knifemakers and
nobody has ever said anything about metalic soaps. Nobody has ever
complained about contamination of their blades that I know of.
Can you elaborate on how you know of this? As I said, I am happy with
my heat treatment as it is but if you can shed light on an unknown, I
will change my process if I can exceed my own tests as a result..
Currently, I can make knives that will pass the journeyman and the
master bladesmith tests given by that ABS and my personal tests are
more demanding. I am really quite surprised that there could be a
problem but I am open to hear what the effects of these contaminates
On Fri, 26 Dec 2003 20:45:39 GMT, Charly the Bastard
On Fri, 26 Dec 2003 19:47:52 -0600, oso firstname.lastname@example.org wrote:
How many knife makers really know shit about metallurgy ?
Talk to someone who works in the automotive industry - particularly
for gearbox production. My car (15 years old) has 1/4million miles on
it and is still going fine. My first car barely made it to 100K.
There's a reason for this, and understanding the subtler points of
long-term surface contamination is a big part of it, let alone using
these same oils for heat treatment.
I'd quench files in water if I were making scrapers or some sorts of
knife, but for general knives or anything that's likely to take a
pounding, then go with oil. The cracking problem is easy to
over-state, but it can happen.
Klein bottle for rent. Apply within.
Slow down, Bob. Anti-foaming agents are usually lithium-based metalic
soaps, and they will induce surface brittlness in certain alloys,
especially the chrome-heavy ones like stainless. (damn stickyspacebar...)
Old motor oil contains combustion formed acids, and sulphate compounds that
the foundries work very hard to remove from the steel. I don't know what
alloys you work, but that kind of stuff I don't want in my work. I use USP
Mineral oil, Vet-grade, which is about a 20-weight at room temp, and it has
produced consistent and reliable results for every oil-hardening steel that
I normally use. YMMV
I just get a little twisted when people challenge the knowledge of
people they don't know. If is fine to say they disagree with
something but to just make a blanket statement that knifemakers don't
know shit about metallurgy is irresponsible. We may not know
EVERYTHING but then again, we don't need to know everything. We need
to know enough to make a quality knife, not necessarily how to get and
extra 150K miles out of our cars.
As I stated earlier, my knives pass the tests I put them through and
that is better than the factory knives can do. I would take one of my
knives into a situation where I had to depend on the quality of the
knife before I would take any factory knife.
When you said to ditch the tranny fluid, I responded with a request
for more info and admitted that there could be something better and
wanted you to share your knowledge.
I have actually used mineral oil in the past. I used it at another
knifemakers shop and did not like the results. Now, I had never used
it before and had not done all of the tests I would do to get the heat
treat correct like I would in my shop. I just followed the heat
treating guidelines the other knifemaker used for his knives. The
result was a knife that did not pass my tests, so I never went back to
it afterwards. It now may need another look. If it can make a better
blade than what I am making now, I will switch in a second. If I
can't improve on my end product, I will stay with what is working now.
I appreciate your pointing out the potential issues tranny fluid could
I just wish people would talk to others here like they would talk to
them face to face. There was no reason for that rude reply, it could
have been done politly and added to the conversation, taking the topic
to another level. Instead, it is just annoying. To jump into a
conversation with smart ass remarks really needs to be backed up with
something more than just "cause I said so" arrogance. He said he
would quench files in water but that creates a vapor barrier and does
not do as good a job as quenching in preheated tranny fluid, proving
he does not know what he is talking about. Using files is usually done
by beginners and experienced people use new steel of thier choice so
they can more accurately heat treat for performance. Sounds to me
like he is trying to sound like he knows what he is talking about but
really just heard a car guy say something similar.
Thank you Charly for explaining your reasons.
On Sun, 28 Dec 2003 14:34:13 GMT, Charly the Bastard
On Sun, 28 Dec 2003 11:26:15 -0600, oso email@example.com wrote:
Well if you don't like it, lay off the sarcasm from your side, "I have
just learned that there are NO blacksmiths in this world that cannot
forge weld. " then you might not get it thrown back at you so much.
I don't understand metallurgy. I say this, because I have friends who
teach the subject and I know I don't know a fraction of what they do.
I've worked in car plants and press shops (building SPC measuring
rigs) where how to make something last 10 million cycles was a done
deal and now they were pushing for 100 million. These are the people
who really care about metallurgy, even the subtle stuff that doesn't
show up in normal service.
Then you tell us that backyard smiths know all there is to know abot
quenching oils on the basis of "I haven't had any problems so far".
All this, from a trade that you don't think even needs to know how to
The sarcasm was not meant for you. The person it was directed at is
very capable of defending himself and made his point of view known so
don't feel like you need to help him out..
As for you, you admitedliy do not know metalurgy so why are you even
bothering to try to tell others anything?
I haven't had any problems so far is correct and I TEST my blades, did
you miss that or did you not understand that? I was not sarcastic to
the guy that told me about potential problems, I pursued his reasons
for saying so. I did not say that backyard smiths know all there is
to know about quenching in oil. Re-read the post.
Just because you know someone that might know something does not give
you any knowledge at all and therefore you look like a fool getting
onto this discussion.
What have YOU done to give YOU any insite into this topic at all?
On Mon, 29 Dec 2003 18:52:50 +0000, Andy Dingley
As a new person to this group that is thinking about getting involved in
black smiting, a couple of good answers to this question would be much
better then these flame wars you folks seem so will to wage.
I have been around Usenet for over 8 year, and it never ceases to amaze me,
how people get sucked into these battles of the egos..
So, as Cockahdewall Youbetcha asked,
Oil or Water??
Thanks in advance, and please keep the flames in the forge:-)
It all depends on the steel.
If you are buying steel, it is easy to tell what to use.
If you are using good quality files like Nicholson, they are 1095
steel. You would use oil heated to 125 degrees for your quench.
If you are using O1, you would also use Oil
If you were using W1, you would use water.
If you are using leaf springs they can be 1095, 1084 or 5160. All
would use oil but the tempering is different.
Do you know your steel? If not, I would use oil and then test your
results. If they are not satisfactory, normalize and then try again
with water. TEST again.
On Mon, 29 Dec 2003 22:32:42 -0500, "Douglas R. Probst"
Well Doug, it depends on what kind of steel the file was made from in the first
place. Nicholsons are made from W-2, which is a water-quench alloy. Was it a
Nicholson? Or was it some no-name from China made from Bhob-knows-what kinda
Quench is about the rate of temperature drop in the workpiece. Brine (saturate
saltwater) is the fastest, then pure water, then oil being the slowest. When
steel is heated past about 1475 degrees, the carbon 'goes into solution' in the
matrix, and forms a carbide film around the individual ferrite crystals. When
you quench, the rate of temp decrease has a controlling effect on the final
size of the crystals. The faster you cool, the smaller the grain size, and the
more carbide is exposed at the edge. It's this carbide that is the hard part,
the ferrite stays soft, so the more carbide exposed in the edge, the better the
blade will retain sharpness. This is the rule for plain carbon steels, the SAE
10xx series. When you add alloying agents, like chrome or molybedamned or
vanadium or manganese, then the rules change, and you start needing oil because
a fast quench can produce internal stresses capable of actually tearing the
work apart in the tank. (I have a water-quenched piece of SAE5160 on the wall
to remind me of this, little hairline cracks all through it. But damn, a file
won't touch it, so it went above Rockwell C-65.) The quench will push the work
to 'full hard', then the draw, a low temp reheat, will relieve the internal
stresses at the expense of some of the hardness. Final temper is a compromise
between absolute hardness and the ability to absorb deflection loads, like a
spring, or repeated impact loads, like a hammer. Clear as mud, yes?
Just to make sure, did you catch the idea that your files may or may not
be "hardenable" steel thru and thru? If they are simply case-hardened
lower carbon material, they won't work well. Case hardening is usually
only "skin deep", so if I were you, I'd take a sample of the file I'm
going to use and grind ALL the teeth off, plus 020" or so and then see
if that material is hard or not. Alternately, you could heat a sample
to non-magnetic and then quench it in water. If it gets brittle when so
quenched, then it will work for you.
I'm a general blacksmith, not at all a knife maker, but with all the
work that goes into a blade, I think I'd invest in known, brand new
material for my knife stock. In the end, the cost of the stock will be
but a small part of the total "cost" of the blade.
Cockahdewalk Youbetcha wrote:
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.