Material. Old axle shaft (half shaft) from motor vehicle or tractor (even a front stub axle will do); a piece of railway-line steel; an old plough beam; 25-mm round-section mild steel.
Additional tools. Top and bottom fullers about 25 mm; eye drift as for Job 16; slot punch made to suit, about 22 mm along the edge; set hammer; flatter; sharp hot set; top and bottom swages of 22-mm diameter.
The most popular ball-peen hammer is the so-called engineer's ball-peen hammer. It is more difficult to make than the hammer described in Job 16. It is a more sophisticated tool and is useful to craftsmen other than blacksmiths. Figure 165 shows a hammer full size and of dimensions suitable for practice. It weighs about 200 g. Larger and smaller ones can be made in the same way. The dimensions given are not critical but, if followed, they will give a well-balanced tool.
This job can be done using round- or square-section steel, but round is easier to work with. Square gives more material around the eye but requires additional work in rounding the ends. Axle steel 25 mm in diameter or larger is as good a material as any for this job. Other types of scrap require considerable forging to prepare the blank. Mild steel is the easiest to work but needs to be treated, as in Job 18. If possible, use a hand length of material, leaving tongs to be used only for the last operation.
Mark off as in Fig. 166 A with prominent centre-punch marks. Heat to a bright red to yellow heat and punch a slot hole as described in the previous job. Upset a little to open the hole. Drive in the drift alternately from each side of the hole but not to its full depth. Fuller (Fig. 168) to give the form shown in Fig. 166D. Use the 25-mm top and bottom fullers for this with the metal at a bright red heat. The fullering need be only 3 to 4 mm deep. Notice that the fullering should indent the metal to a square section as close to the eye as possible (Fig. 166D). These four corners are then fullered to give an eight-sided section.
Next, at a bright red heat and with the drift in the eye, hold the work over the rounded edge of the anvil and at an angle to the anvil face (about 4 degrees). Flatten the sides of the eye (Fig. 169). Work alternately from each side, spreading the metal to give the form it will eventually take when cut from the bar (Figs 167B and C).
The drift will also need to be introduced from alternate sides in turn, driving it in a little farther each time as the metal is spread until the full size of the eye is reached. It is important to keep the work as straight as possible during this operation. If you need to, you can do a little more fullering now to finish that part of the work neatly.
Reheat to a bright red heat, slightly cool the eye to prevent bending and cut off the job from the bar with a sharp hot set (Fig. 170).
Select or adapt a pair of tongs that will fit well over the face end of the job, bring the ball-peen end to a bright red heat and reduce its diameter to 22 mm (Fig. 171). This can be finished in top and bottom swages if they are available. Bring to a red heat all over and cool slowly. The face and ball peen are finished by grinding or filing to the form shown in Fig. 167D. Notice that sharp edges are removed from the flat face.
Hardening is carried out as in Job 16. If mild steel is used, see Job 18. When a neat and clean forging has been produced, it is worth cleaning up all over with a wire brush. Some additional filing of the eye may be done to give a pleasing appearance.