Mechanical Damascus: Pattern Welding
This photograph above is a detail from the blade of a yataghan and is characteristic of Turkey and the areas surrounding it. In addition to laminated (layered) steel on its edge and back, the blade shows three bands of patterned steel running the length of the blade. The pattern, created from a twisted rod incorporated into the blade for each band, repeats itself along each band with slight changes as curved patterns merge into a zone where the appearance is more that of diagonal lines. Another example of pattern welding in a kindjal is available (48 kb). Similar patterns may also be seen in a keris. The twisted rod technique by which this pattern has been achieved is called pattern-welding and is essentially identical to that used in medieval Europe during the Migration Period and Viking Age.
This is a photograph of a Viking sword blade with three alternating bands which further alternate between twisted (to the left) and straight (to the right) areas. Notice that on the left the pattern is made up of fairly straight lines creating a herringbone effect, however in the center of the photograph, the upper band shows a more curved twisted pattern such as is seen deeper in a rod. More information on pattern welding is available on-line in Adobe PDF format, as are illustrations of examples of mechanical deformations modeled in clay.
While traditional, classic pattern-welding consisted of twisted rods composed from a stack of strips (for example having 7 alternating elements) of contrasting alloys, each strip the length and width of the overall rod, European barrel makers began in the late 19th Century to create more complex designs from arrays (as viewed from the end and as compared with the above, having 49 elements) of more components, such that repetitive lettering or designs ensued. This tradition has been continued by some modern bladesmiths.