Material. 5-mm carbon-steel plate (old plough or harrow disc is ideal).
Additional tools. Bottom swage, size depending on thickness of metal but about 25 mm; 12-14-mm set hammer; hot set.
From carbon-steel plate cut either the pattern shown in Fig. 139 or one of your choice. Cutting can be carried out by heating and using a hot set. Marking the pattern can be done with white chalk, which is visible even at red heat. After cutting, edges can be heated and hammered to give a better finish or, if a grinding machine is available, the edges can be ground before proceeding with the work.
Position the bottom swage in the anvil, have the top fuller at hand, heat the tang end to a good red heat and fuller to a half-round section, as in Fig 140 and Fig 141. Reheat and carefully forge the tang to a tubular section for about one-third of its length, with the remainder in more of a U shape. Reheat and carefully forge to a square tapered section. With a little flux, a light welding heat may be taken on the end and forged to give a solid point, which helps when a shaft is fitted (Fig. 142). Reheat the blade around the lower part of the fullering and finish the sides and end of the fullered part, as in Fig. 143. Reheat and true up the work and set the tang and blade to the angle suitable for the person who is to use the tool. Sharpen the working edge with a grinding machine or file.
Usually plough-disc steel is sufficiently hard for tools for manual work without heat treatment. However, the hoe can be hardened and tempered if necessary. Heat about 50 mm of the blade, from and including the edge, to a dull red heat and quench in oil. Clean the edge with a piece of sandstone or carborundum stone until shiny. Place on top of the fire with the edge clear of the centre of the fire and slowly reheat until a dark brown colour is observed, and quench again.
Some care is required in heating to ensure that the blade is evenly heated across its width. This can be accomplished by constantly moving the job from side to side in the fire. If temper colours begin to appear in one spot before another, the part showing slight colour must be moved farther away from the centre of the fire. A little practice soon develops the skill needed.