Daniel Rotblatt on wed 26 may 10
Paul,
I used to make and sell knives. O-1 is a great steel, and I have made
many knives from it. It will rust, though not much different from
mild steel. Heat treating is a two step process; first you harden the
steel by heating it past a critical point (usually red hot) then
quickly cool it by quenching in an appropriate liquid which cools it
at the right rate. Second you temper the hardness by heating it to a
lower temperature. What you are doing is creating a mix of two
crystal structures in the steel - one for hardness and one for
toughness. The first process creates a crystal structure between the
iron and carbon atoms that is very hard, but also very brittle. A
hardened piece of steel that is dropped can easily shatter. The the
tempering process converts some of these hard crystals to a different
crystal structure that is tough and flexible. The combination of the
two gives a hard and tough steel.
Here's the basic process to heat treat O-1 steel (the O stands for oil
hardening):
Once the metal is formed into shape:
1) heat to a dull red in an indoor setting (like a garage) then quench
in oil (transmission oil is good, but motor oil is fine - you can use
vegetable oil too). Different amounts of ambient light will effect
what the "proper" red color is, so it may take a try or two to find
the right color. Overheating will cause a larger grain structure and
weaker end product, so it's better to start with a less bright red and
work up until it hardens.
2) Once cool, use a dullish file and see if it will bite into the
steel. Be somewhat careful, the steel is really brittle. If the file
slides off the steel like it was glass it has hardened, if it bites
into the steel do #1 again, but get the steel a little hotter. Note:
if the steel got hot enough to harden, the carbon will have flaked off
of the hardened steel a bit - you'll know what I mean when it happens.
3) Clean all oil off the steel with acetone or similar solvent.
4) Place the steel in an oven and bake at 375-475 degrees. 375 will
produce a harder but more brittle blade, 475-500 is more like a
spring. I'd go with 375. Kitchen ovens vary up to 50 degrees, so if
you have a oven thermometer that would help. Bake for at least 30
minutes. The wife may or may not go for this...
This will give you a tool that is far superior to mild steel. When
you sharpen it, do not sharpen all the way since the thin edge will
heat up too fast and cool too fast. leave about 1/16" of flat on the
edge then when you are done sharpen on a wet stone by hand or really
carefully with a grinder quenching in water after every pass or two
(if the steel heats up, and turns color - like purple or gray - you
have lost the hardness, if it turns straw colored or yellow that is
still OK).
Dan Rotblatt
www.RotblattSculpture.com
On May 26, 2010, at 1:58 PM, Paul Borian wrote:
> i need to make some more trimming tools. for a long time i used mild-
> steel
> concrete ties, bent into an L shape and just dealt with the fact
> that they
> don't last long because they were free (left over from when the
> house i live
> in was built).
>
> but i found out today it would only cost $10/tool to make them from
> O-1 flat
> bar (1/8" X 1") so i was thinking to heat, bend into an L, sharpen
> really
> well then heat up to a bright red and quench in oil.
>
> is it that simple or am i missing something? Has anyone done this?
>
> thanks,
> Paul
Paul Borian on wed 26 may 10
i need to make some more trimming tools. for a long time i used mild-steel
concrete ties, bent into an L shape and just dealt with the fact that they
don't last long because they were free (left over from when the house i liv=
e
in was built).
but i found out today it would only cost $10/tool to make them from O-1 fla=
t
bar (1/8" X 1") so i was thinking to heat, bend into an L, sharpen really
well then heat up to a bright red and quench in oil.
is it that simple or am i missing something? Has anyone done this?
thanks,
Paul
Arnold Howard on wed 26 may 10
From: "Paul Borian"
> but i found out today it would only cost $10/tool to make
> them from O-1 flat
> bar (1/8" X 1") so i was thinking to heat, bend into an L,
> sharpen really
> well then heat up to a bright red and quench in oil.
-------------
Tool steel manufacturers publish heat treating formulas for
every steel. You can heat treat your own tools in a small
kiln. I've done it even in a manual Paragon Q-11A and
adjusted the hold time with an infinite control switch. (It
is far easier with a digital kiln, of course.)
To reduce the carbon scale on the tools, wrap them in
Inconel foil, which is like a very heavy aluminum foil.
Place a piece of wood inside the foil packet to create a
reduction atmosphere.
This manual contains formulas for several steels and
explains the process:
http://www.paragonweb.com/files/manuals/IM70_HT_KM_Manual.pdf
Sincerely,
Arnold Howard
Paragon Industries, L.P., Mesquite, Texas USA
ahoward@paragonweb.com / www.paragonweb.com
jonathan byler on wed 26 may 10
clay is so abrasive that even harded too steel isn't going to last for
long. the other problem that you have to fight with is that high
carbon steels tend to love to rust, which also takes away from your
sharpness pretty quick, though maybe not as fast as the regular tools
we get.
bison makes really nice things that do work out of silicon carbide.
you just have to not drop them on the floor.
On May 26, 2010, at 5:42 PM, Mike wrote:
> Hi Paul,
> Here's a really informative site on just what you are thinking about
> doing:
>
> http://www.threeplanes.net/toolsteel.html
>
> All my trimming is done soft with dull tools, so no need for an edge,
> but now you've got me thinking about hardening and tempering my
> tools to
> keep that dull edge darn near forever.
>
> Thanks,
>
> Mike
>
> Mike
> in Taku, Japan
>
> http://karatsupots.com
> http://karatsupots.blogspot.com
>
> Kiln Building Workshop, Oct. 15 - 22
>
> http://karatsupots.com/workshop2010/workshop2010.html
> http://karatsupots-workshop.blogspot.com/
>
>
> (2010/05/27 5:58), Paul Borian wrote:
>> i need to make some more trimming tools. for a long time i used
>> mild-steel
>> concrete ties, bent into an L shape and just dealt with the fact
>> that they
>> don't last long because they were free (left over from when the
>> house i live
>> in was built).
>>
>> but i found out today it would only cost $10/tool to make them from
>> O-1 flat
>> bar (1/8" X 1") so i was thinking to heat, bend into an L, sharpen
>> really
>> well then heat up to a bright red and quench in oil.
>>
>> is it that simple or am i missing something? Has anyone done this?
>>
>> thanks,
>> Paul
>>
>>
Mike on thu 27 may 10
Hi Paul,
Here's a really informative site on just what you are thinking about doing:
http://www.threeplanes.net/toolsteel.html
All my trimming is done soft with dull tools, so no need for an edge,
but now you've got me thinking about hardening and tempering my tools to
keep that dull edge darn near forever.
Thanks,
Mike
Mike
in Taku, Japan
http://karatsupots.com
http://karatsupots.blogspot.com
Kiln Building Workshop, Oct. 15 - 22
http://karatsupots.com/workshop2010/workshop2010.html
http://karatsupots-workshop.blogspot.com/
(2010/05/27 5:58), Paul Borian wrote:
> i need to make some more trimming tools. for a long time i used mild-stee=
l
> concrete ties, bent into an L shape and just dealt with the fact that the=
y
> don't last long because they were free (left over from when the house i l=
ive
> in was built).
>
> but i found out today it would only cost $10/tool to make them from O-1 f=
lat
> bar (1/8" X 1") so i was thinking to heat, bend into an L, sharpen really
> well then heat up to a bright red and quench in oil.
>
> is it that simple or am i missing something? Has anyone done this?
>
> thanks,
> Paul
>
>
Mike on thu 27 may 10
Sorry, just one more note on this web page with information on hardening
tool steel:
http://www.threeplanes.net/toolsteel.html
Check out the link at the top of the page to the author's list of Spam
Haiku, it is a hoot! A new literary genre...
Mike
Mike
in Taku, Japan
http://karatsupots.com
http://karatsupots.blogspot.com
Kiln Building Workshop, Oct. 15 - 22
http://karatsupots.com/workshop2010/workshop2010.html
http://karatsupots-workshop.blogspot.com/
(2010/05/27 5:58), Paul Borian wrote:
> i need to make some more trimming tools. for a long time i used mild-stee=
l
> concrete ties, bent into an L shape and just dealt with the fact that the=
y
> don't last long because they were free (left over from when the house i l=
ive
> in was built).
>
> but i found out today it would only cost $10/tool to make them from O-1 f=
lat
> bar (1/8" X 1") so i was thinking to heat, bend into an L, sharpen really
> well then heat up to a bright red and quench in oil.
>
> is it that simple or am i missing something? Has anyone done this?
>
> thanks,
> Paul
>
>
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