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5. Pocket or cleft method of making a T-shaped joint

Material. Flat section mild steel as available; for practice, metal of about 30 x 10 or 12 mm is suggested, one piece 250 mm long and another about 150 mm long.

Additional tools. Sharp hot chisel with a curved cutting edge.


This preparation in flat section steel produces the strongest T-shaped joint (Fig. 30). Bring the centre section of the longer piece to a good yellow heat, cool with water to restrict the heat to a length of about one and-a-half times the width of the bar. Upset until the metal is 25 to 50 percent thicker than its original size. Keep the extra metal to one side by working over the tool hole of the anvil (Fig. 31). Thin down the upset edge a little (Fig. 32), then split it with a hot chisel (Fig. 33) to form a cleft with two lips.

Next, take the shorter piece, upset one end and draw down to an abrupt flat-edged point (Fig. 34). Heat the longer piece and then drive the point of the short one in to the cleft in the longer piece (Fig. 35), close the lips on to it, then separate the two pieces. At this stage it is a good idea to spend a little time practising taking the pieces from the fire and rapidly positioning them for

Agricultural engineering in development


Agricultural engineering in development


Agricultural engineering in development


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