Stock Removal Blade; refers to a blade which has been shaped from a rolled or precision ground piece of steel stock using files and/or a belt grinder..
Damascus; refers to a material which is made by the process of pattern welding. Basically what it amounts to is to laminate alternating layers of carbon steel and either wrought iron or mild steel or even pure nickel. This kind of steel is made by forge welding the various layers together then folding the forged billet over and repeating the process. By using simple multiplication, one can quickly see that after 16 folds you get approximately 65,000 layers of steel.
Forge Welding; is a process by which two pieces of steel are joined together. It is somewhat like modern day welding, except that it is its ancestral equivalent. By hammering two pieces together once they are at the proper temperature and as long as their mating surfaces are clean they molecularly fuse together.
Pattern Weld; is a forge weld of two or more kinds of steel including a high carbon steel (assuming that we are making knives here...). Once the forge welds are complete and we have the proper amount of layers we can impart various mechanical deformations to the billet of steel thus displacing the layers. This will occur naturally during the forge welding process and the layer building folds from the impact of the hammer on the steel. However, very interesting patterns can be created by drilling holes, hitting the surface of the billet with cold chisels, twisting the metal and inlaying other metals into the billet. Actually, there is no limit to the patterning which can be created, it is basically always being improved upon by knife makers in order to get that ultra artistic design. The layers of steel become apparent in the blade blank once it has been ground to shape, heat treated, polished and etched in an acid solution. The Etching is basically what makes the design visible.
Ladder Pattern; many styles of ladder pattern Damascus have been made. It all depends on the amount of layers of steel in the billet and how the surface of the billet (before final edge grinding) is cut up with a cold chisel. The "ladder" is made by cutting the surface of the billet on both sides with equally (or not equally, depending on your personal disposition...)spaced cut grooves. The billet is then flattened and the knife making process started.
Butterfly Pattern; is basically the same as the ladder pattern, except that you cris cross the grooves cut into the billet creating "X"s
Pool and Eye Pattern; is accomplished by drilling holes into the billet approximately 1/4 of the way through it and then flattening it. It creates a bulls eye effect, although quite random. It is kind of a hit and miss situation.
Twisted Pattern; is created by twisting, as the name implies, the billet of steel once it has been forge welded and a fair amount of layers of steel have been created. The final outcome of this pattern is dependent on the grinding of the blade blank.
Waterfall Pattern; is basically a twisted pattern which has been flat forged instead of having been ground into shape. The difference in stock preparation is subtle as are the results.
Maiden's Hair Pattern; this pattern requires more layers of steel than the Waterfall. It should also be tightly twisted and have its edges ground round prior to flat forging.
Cable Damascus; this is basically made by forging elevator cable into a billet of steel. Since certain types of elevator cable contain carbon steel wire, it is ideally suited to becoming an edge holding device. The forge welds between the small steel wires give the finished blade a nice splotchy look.
Other types of Damascus; nowadays, many knife makers are trying to forge everything including the kitchen sink! Wally Hayes has made knife blanks from chains, cable as well as regular tool steels. I even saw one made from a motorcycle timing chain. The sky is basically the limit here. As long as there is carbon in the steel, it can make a great knife blade.
Heat Treating; is the process by which a knife blade has the quenching stresses removed from it through short to extended periods of heating inside a heat treating furnace. This process reduces the hardness and brittleness of the blade which is inherited from the quenching process.
Quenching; is the process by which a knife blade attains its maximum hardness. The blade, once it has been completely shaped, but not to its final polish, is heated up to its critical temperature either using a torch, a furnace or with the forge, and then quenched in the proper medium, according to the type of steel.
Critical Temperature; is the temperature at which a piece of steel becomes non-magnetic. Many knife smiths just use a cow magnet in a vise to check the steel during the heat to see if it has reached critical temperature.
