Page 37 - Australian Wood Review №103 2019
P. 37
TOOLS & EQUIPMENT
1. Veritas Tools (Canada) now manufacture
chisels and plane blades in PM-V11
steel. Their own test results determined
this alloy will provide a balance of edge
retention, impact resistance and ease of
sharpening. Photo: Lee Valley, Canada
2. Good quality high carbon steel chisels
like these from Titan are good value
and perform very well. Avoid the upper
example (firmer chisel) as you may
have difficulty fitting them into a side-
clamping type of honing guide.
3. There are many examples of high quality
Japanese chisels of the water quenched
high carbon steel type. If you use
2 a honing guide be aware that some
examples are either too short to fit
into a honing guide or have a triangular
section which also does not fit.
Photos this page: Peter Young
3
here is now a confusing array of it’s also true that the better the edge There are three important steps
Tsteels available for both chisels retention, the more expensive the in steel manufacture. Firstly the
and plane blades and choosing the item is going to be. All cutting tools ingredients must be heated for the
right steel for your purpose can be need to be frequently sharpened alloy to form. Secondly, the steel must
daunting. I am not a metallurgist to perform at their best, it’s just a be cooled (quenched) but in such a
but I do have some experience with question of how often you sharpen way as to retain hardness. Thirdly, the
various types of steel in different and how long that takes. hard (but brittle) steel needs to be
applications, so what follows is my tempered to reduce brittleness.
personal take on this issue. Other Steel types
experienced people may have different Steel is essentially an alloy of iron and Tempering must be done in a very
views so it’s always good to get a carbon. The addition of only very small controlled manner as uncontrolled
number of opinions. A good source amounts of carbon (as little as 0.2%) tempering can reduce hardness and
of information about steel types and turns iron into an incredibly strong thus edge life. A good example of
sharpening techniques is Ron Hock’s but malleable material and most of uncontrolled tempering (heating)
book The Perfect Edge published by the steel we come across is in this low is when blades are being ground on
Popular Woodworking Books. carbon form. Adding more carbon a grinding wheel. It is very easy to
increases hardness (resistance to overheat the thin cutting edge and
The important take-home message compressive deformation) and tensile thus lose hardness exactly where
is that choosing a suitable chisel or strength (resistance to elongation). you want it. Cooling the blade
plane blade is a compromise and in water when grinding is also a
there are a number of factors which With about 0.8% carbon, steel is common practice but this should be
need to be taken into consideration. easily able to be hardened with discouraged for all except high carbon
Different people will place a different heat treatment. With improved steel. A2 steel is especially prone to
emphasis on each of these factors. hardness comes improved resistance losing hardness with uncontrolled
to abrasion or for the woodworker, heating and you should only use a
In many magazine reviews there improved ability to hold a cutting heat sink, for example, a metal block
is a very heavy emphasis on edge edge. However if too much carbon for cooling.
retention because logically the better is added (more than 1.5%) the steel
the edge retention the longer the becomes brittle with fracturing of Tool steels are described according to
period between sharpening. However the cutting edge. the method used for quenching.
www.woodreview.com.au 37
