Blacksmithing
and Cutlery
by Gérard HEUTTE
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Making a forged knife blade
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Here are successive operations ending up to a usable blade. It is mainly a checklist
intended for the neophytes.
The various operations are not detailed here...
General advices
Some major points to recall:
> Have an idea of what you want to obtain. For a first time, limit yourself to a
reasonable blade size, like a 100 mm length blade on 25 mm wide and 3 to 4 mm thick.
> Choose a "simple" steel, like the XC75. Avoid scrap steel which you are unaware of
its characteristics.
> Begin the forge operations by heating steel enough (orange red). Then, as the form is
more precise and the generated deformations decrease, also decrease the temperature of
work.
> Do not forge too cold. Put the parts in the earth as soon as it becomes too dark.
> For a first knife, the forging of a full-tang blade is simpler.
Making a flat part
The first thing to do is to create a flat part whose section must correspond to the broadest
section of the knife. In our example, you will seek to obtain a flat part of
25x4. As an easier way, you can buy a standard plane part at the right dimensions.
Do not go to the following step as long as a correct plane part is not obtained.
It is necessary to have sufficient length for the blade and the handle.
Some information of
detail about
planing, the stretching and the making a plane part.
Shaping the blade by forging
Refine the tip. And make gradually the edge while rectifying the blade. Take care to
leave a little thickness on the edge (approximately 1 mm, even more on long blades).
Here are the details for forging a
blade.
A similar work for the forging of an
integral blade.
Annealing
Heat the steel to the temperature of hardening.
Cool it slowly in the dying fire of the forge (all the night) or in a can filled with vermiculite
(a few hours).
Some information on
annealing.
Coarse grinding
It is possible now to refine the work
made with forging. It is done by abrasion. Many
different tools can be used. Simplest way is to work with the file.
Start by the outline of the blade. Then make the side (ricasso, tang). To finish, work on the edge.
Leave a half millimetre of matter on the edge.
For more details, see blade shaping by
file. If needed, drill the holes.
Normalization
Heat the steel to the temperature of hardening.
Cool it within the free air. Heat again as soon as the blade is dark. It is advised to make
at least three normalizations.
Some information on
normalization.
Hardening
Heat the steel to the temperature of hardening (Red).Take it with tongs and soak it quickly
in the adequate medium.
As soon as the blade is cold, check that the hardening has occurred by testing the edge with a file.
Some information on
hardening and
quenching mediums.
Tempering
Immediately put the blade in a oven preheated at the temperature of tempering (in general
from 200 to 240°C). Make two successive cycles by letting the blade cool between them.
Some information on
tempering.
Completion
Work surfaces with abrasives more and more finer, up to the level of completion wished.
This operation will concern the edge at least.
Sharpening
At the end of polishing, the knife is already sharp. It only remains to use a fine stone on
the edge (like coticule stone). It is possible to do this operation before
or after the assembly of the knife.
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