The scriber or scratch awl, Fig. 61, is made in many forms, but consists essentially of a cast-steel rod about 8 inches long and 3/16 inch diameter, with a long, slender, hardened point at each end. Frequently one point is bent at right angles to the shank. As the name indicates, this tool is used for marking lines on the surface of metal.
Fig. 61. Forms of Scribers Courtesy of L. S. Starrett Company, Athol, Massachusetts.
Where the same lay-out is to be many times repeated, templets are used. This method avoids the necessity of making measurements in the laying out of the work.
The marking templet consists of a piece of the same shape as the finished article. It is usually laid on a flat surface and held fast by iron clamps as shown in Fig. 62. The outline is then marked on the surface with a scriber and sometimes emphasized by prickpunch marks.
Fig. 62. Steel Clamps.
The filing templet is of the same character as the marking templet except it is hardened. It is clamped in the vise with the piece to be shaped, and the surface filed down to coincide with the form of the templet.
Where holes are to be drilled in duplicate, a templet known as a plate jig is used. These are made so that they fit over the piece to be drilled and, when clamped in position, indicate the location of the holes by means of hardened steel bushings set in the templet.
The making of templets and jigs is one of the finest branches of the machinist's work and is generally classed under the head of "Tool-Making". The rapid and economical production of machine parts in quantity depends largely on the tool-maker, who must, therefore, be considered the highest type of machinist.