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19. Forging an axe head from low- and high-carbon steels

Material. 280 mm of 50 x 8-mm flat mild steel; scrap piece of high-carbon steel about 50 x 50 x 4 mm (old plough disc or ploughshare will do); for welding flux, use borax or a commercial brand for the oxyacetylene welding of cast iron; clean white sand or powdered sandstone will suffice if nothing else is available; two pieces of 6-mm rod.

Additional tools. Axe eye drift (Fig. 132); bent bar; hot set; set hammer; flatter.


In addition to producing an extremely useful tool, this job introduces the combining of high- and low-carbon steels to make a cutting tool. New points for old ploughshares can be made by using this technique, and chisels, plane irons and gouges for woodworkers can be produced. With care, cast-iron scrap can be used instead of high-carbon steel. A good flux is required to reduce the oxidation of the high carbon steel during welding. Borax or the cast-iron welding flux are both active fluxing agents and will help to dissolve any oxides formed. Clean white sand can be used, but this merely forms a molten barrier to the atmosphere and is rather messy.

To begin, the mild-steel bar is heated to a bright red heat and bent into a U shape and closed around the drift (Fig. 133). The piece of high-carbon steel scrap is inserted as in Fig. 131B. The whole is heated and then two holes are quickly punched beneath the eye but including the high-carbon steel. Two small pieces of 6-mm rod are inserted as rivets (Fig. 134). These will hold the pieces in the correct position while a welding heat is taken. Tongs as used to hold the hammer eye in Job 18 will serve to hold the axe eye. It is important that these tongs not be allowed to become red hot; they must be cooled frequently.

Agricultural engineering in development


Agricultural engineering in development


The work is positioned well into the fire and a welding heat taken close to the eye. In fact, part of the eye will also reach welding temperature. Heating must be slow to give time for the heat to spread through the work, and frequent turning of the work in the fire is necessary. When the work reaches a good yellow heat, flux is sprinkled on it, particularly along its edges. Heating continues up to welding temperature. The work is then positioned on the anvil (Fig. 135) and rapid heavy hammer blows should be applied close under the eye to weld the pieces into a solid mass. This weld can be finished with a set hammer if desired. During this operation the eye will be slightly reduced in size.

A second welding heat is taken on the edge of the work opposite to the eye. Slow heating is again advised and care must be taken to ensure that all unwelded parts are included in this heat. Quick and heavy hammer blows should be applied to the job, taking care to cover the whole piece with hammer blows. Shaping of the axe head can also be started during this heat. A third welding heat will be required to consolidate the metal and to complete the shaping (Fig. 136). The metal should be spread to a larger size than the finished axe head and can be finished with the aid of set hammer and finally a flatter. Next, the eye is again brought to a bright red or yellow heat, the drift inserted as in Fig. 137 and the eye set to the drift and stretched slightly as in Fig. 138. This should be carried out from both sides of the eye, leaving it slightly smaller in the centre than at the openings. Note that the axe eye drift is shaped to leave this restriction in the middle of the eye hole (Fig. 132).


Agricultural engineering in development


Agricultural engineering in development


Agricultural engineering in development


Agricultural engineering in development


Reheat and trim the axe head to size and shape using a hot set. True up the job, heat to a good red heat all over and allow to cool slowly. The job can be ground or filed to final shape and its cutting edge formed by filing. Heat the job to a dull red heat (visible in the shade) for a distance of about 30 mm from but including the cutting edge and quench in water. Tempering should not be necessary, but if signs of chipping are noticed on the edge during use the work can be tempered at a dark straw colour. Final sharpening should be carried out using a fine carborundum stone.

The sizes given are for a small axe but larger ones can be made using the same technique.

Agricultural engineering in development


Agricultural engineering in development


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