Ever wonder how they cut odd-shaped shield inlays before dremels and cnc?
This is just an excerpt, one of five pages:
http://contrib2.wkfinetools.com/tweedaleG/tlParser/tlParser-01.asp
The Parser in Action
To demonstrate the parser to me, Stan took a small piece of buffalo horn (which would later form the handle of the pocket knife). He sandwiched this between a piece of wood (for backing) and the shield template. It was then put in a vice. Meanwhile, he strapped the breastplate around his waist and placed the pointed end of the parser into a dimple in the breastplate. The two-pronged cutting end of the tool was then inserted into the template.
Because the prongs are sprung, they hold fast inside the template and when the tool is rotated have a natural tendency to follow the contours of the template (even into the sharpest corners). It is important that the prongs are made precisely, so that they can pass each other inside the template as they rotate.
Stan is now ready to cut the shield hole. This is done by quickly moving the bow/fiddlestick back and forth (rather like a cellist playing an instrument). The cutting prongs rotate rapidly and become a blur. In seconds, the job is done and the cavity inside the buffalo horn is hollowed out. The shoulders in the cutters (which rest on the template) prevent the drill from cutting too deep.
Needless to say, the job requires practice to do it well. There are many wrinkles to ensure a successful outcome. Stan tells me that when cutting a shield hole in mother of pearl, he uses a small shaving brush to wet the pearl. It is such a hard material that a little lubrication enables the parser to cut more smoothly.
The scale, with its shield cavity cut, can now be incorporated into the pocket knife. It joins a series of innumerable processes, which at the appropriate stage will see the nickel shield inserted and fixed into place. This is done by drilling tiny holes (usually two) through the shield and then riveting it to the inner brass liner of the pocket knife. Countersinking the holes and fitting, filing, and polishing the thin slivers of nickel are an art.
The ideal is a shield which sits snugly in the handle (no matter what the material), with no gaps between the handle and the shield, and the rivets smoothed and polished to invisibility.
As the photographs of Stan’s knives show, he achieves this quite routinely in a wide range of materials (from top: mother of pearl, tortoiseshell, buffalo horn, rosewood, and sambar stag).