Australian Wood Review – June 2019

38 Australian Wood Review

TOOLS & EQUIPMENT

Water quenched steel

(high carbon steel)

These are simple alloys of only iron

and carbon which are quenched in

water. These steels have been around

for a very long time with the quality

varying and improving over time.

Sheffield steel, Swedish steel and

Japanese steel have long been the

acknowledged leaders in the field.

Buying second hand chisels is an

excellent way to get good quality tools

of this type. Expect to pay $30–60

per chisel.

You can also buy new chisels from

makers like Crown, Marples and

Stanley Sweetheart. You may have

to spend some time flattening the

back of new or second hand chisels

but because the steel is relatively soft

this is not a hugely difficult task on a

diamond stone or coarse water stone.

All the older planes, as well as cheap

new models will have high carbon

steel blades.

Oil quenched steel (O1)

A small amount of manganese (Mn)

added to high carbon steel reduces

the quench rate requirement so that

they can be quenched in oil. These

steels distort less with heat treatment

and can be hardened to a greater

depth. They are an excellent choice for

woodworking tools being harder than

water hardened steel but still easy to

sharpen and are relatively inexpensive.

Most of the better known current

manufacturers offer O1 chisels and

plane blades and you can also buy O1

replacement blades for older Stanley

and Record planes. (Note Lie-Nielsen

no longer offers O1 chisels and blades

in their range). Expect to pay about

$50 – $60 per chisel.

Air quenched steel (A2)

These steels have additional alloying

elements such as chromium and

silicon and allow the steel to be

quenched in air, a much gentler

process which results in less distortion

than either water or oil. However

there is a possibility of creating large

carbide particles that may interfere

with precision sharpening and the

durability of a cutting edge so a

balance is needed between hardening

stability and a fine cutting edge.

Because air quenching is a relatively

slow process and the hardening

process may be incomplete, some

manufacturers like Lie-Nielsen apply an

additional cryogenic treatment to A2

steel to improve toughness and aid edge

retention. The steel is cooled to – 195C

in a computer controlled process.

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4. Blue Spruce Toolworks (USA) uses A2
   tool steel hardened and tempered to
   Rockwell Hardness Rc60-61. A primary
   bevel angle of 25° with a 30° micro bevel
   is recommended, which may be increased
   to 35° for extremely hard woods.
   Photo: Blue Spruce Toolworks


5. Clifton tools are made in the UK by Thomas
   Flinn & Co in Sheffield, UK. Their plane
   blades are no longer forged but made
   from O1 steel which is then cryogenically
   treated. Photo: Thomas Flinn & Co


6. Forging Japanese steels using hard and
   soft steel. Photo: Japanese Tools Australia


7. Hock Tools (USA) offer blades in O1
   and A2 steels. Company founder Ron
   Hock is regarded as one of the foremost
   experts on tool steel. His research
   and writings have added considerably
   to our knowledge base of steels for
   woodworking. Photo: Ron Hock


8. The stages of blade manufacturing at Lie
   Nielsen Toolworks, USA involve grinding
   and heat treating. Photo: Lie-Nielsen USA