Feb 13, 2017
It’s episode #97 and I’ve got another JayBurn Journal for
you. A technical article written by Jay Burnham-Kidwell. He’s
a longtime blacksmith residing in Arizona, Since 1974, he has
worked in various mediums and exhibited his work throughout the
world. He works as a studio artist, lecturer, and
demonstrator in all kinds of metalsmithing including jewelry,
copper hollow forms, and blacksmithing. He’s written more
than 40 technical articles for various magazines such as the Anvils
Ring and Anvil Magazine. So a JayBurn Journal titled
“Punches, Drifts, Hammers and Top tools”.
- To produce a tool of quality the smith should use tool or alloy
- Tool steels can be bought new or as a drop or discontinued
stock or as “road kill” recycled steel scraps.
- The average blacksmith shop has adequate resources to forge,
normalize, anneal and heat treat many tool steels safely and most
available tools steels can be forged and heat treated by using
modified methods of the manufacturers recommended procedures.
- Steel is a body-centered cubic crystal at room temperature.
When heated to critical temperature, iron and steel undergo a phase
change and become a face-centered cubic crystal structure.
The hardening process changes the internal structure of the steel
to form austenite. When quenched, the austenite is
transformed into martensite, the hardest constituent in steel.
- Most tool steels generally trade one quality for another: wear
resistance vs. toughness and accuracy vs. red hardness. Wear
resistance is preferable when the tool must hold an edge or stand
up to continued service. Toughness is needed for tools that
are used under stress that may cause breakage. Accuracy
addresses machining after forging and the ability to retain shape
after heat treating. Red Hardness is the ability to retain
shape and hardness when used at high temperatures (punching,
- Normalizing – most, but not all, tool and alloy steels are
normalized after forging by air cooling to remove most of the
stress introduced by the forging process.
- Annealing – heating to critical temperature (nonmagnetic) and
slowly cooling will restore varying degrees of softness in tools
steels. This requires burying the steel in wood ash, lime, dry dirt
or sand. You can use vermiculite, but know that you should
wear a respirator because it contains asbestos.
- Machining – Most, if not all, tools require some grinding,
filing or sanding after forging and before heat treating, as
annealed steel is in a softer state and is obviously easier to
grind or sand.
- Hardening – tool steels are heated to a specified critical
temperature and quenched in the correct medium for optimum
hardening. Tools steels are usually classified as air, water
or oil hardening. Air hardening is accomplished by heating to
critical temperature and cooling in still air. Water
hardening is usually done in a 5 – 10% brine solution. Oil
hardening is accomplished in commercial heat treating oils or
- Tempering – hardening will produce maximum hardness and must be
softened or tempered because the steel is too brittle at this
point. The tool should be tempered as soon as possible after
hardening. Tempering temperatures usually run between 300 –
- W-1 tool steel – a straight carbon, water hardening tool steel
that tends to chip or break. Old files were made from W-1
- O -1 tool steel – a straight carbon, oil hardening steel
classified for coldwork, chasing and repousse.
- S series tool steel – very tough and exhibit very good red
hardness. Due to varying amounts of tungsten and chromium, it can
be a bit tough to forge.
- 4140 – a chromium molybdenum alloy steel that has great
toughness, resists torque and can be used as punches, hammers and
- 4340 tool steel – a close relative to 4140 but with some added
nickel. NEVER quench or cool in water, use only oil.
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