A torsion band is made either from layered or stacked pattern-welded steel.
This band is then twisted. When twisting, tensions are generated inside
the band, having peak values at the edges. To prevent the edge from
cracking, it is advisable to forge the band to an octagonal shape. This
affects most patterns only slightly–only when forging a turkish twist or
inscription patterns will this be noticeable.
Development of the twisted pattern (animated) | The typical twisted pattern,
the star-pattern, is revealed by removing material from
a twisted band. The pattern-style depends on how much material
is removed from the sides. It is not uncommon to remove up to
70% to show a clear star-pattern on both sides of the blade. |
When only a single twisted band is forged to a blade, this is
called a simple twist. The star-pattern covers the whole
width of the blade. This is a very popular pattern, even if
the mechanical performance of theses blades is very poor.
Since the welds are always weaker than the homogenous material,
hundreds of potential crack starting-points are found in the cutting
edge. A crack is most likely to break the whole blade and not just
a section breaking out of the edge. The very common argument for the
twisted pattern–superb cutting ability caused by alternating
hard and tough layers–does not withstand any serious study of the
cutting edge.
If three or more twisted bands are stacked, the resulting pattern is called Turkish twist. Sometimes an eye-shaped ornament is formed by adjacent patterns, the so-called cyclops-eye. In very evenly twisted patterns this eye is more common. | Turkish twist |
© 2005 G.v.Tardy