Bend the metal into a circle and place the scarfs in position, as shown at C, having all edges overlapping slightly and hammered down into close contact. Heat the work for welding, observing the precaution given in the explanation of the former eye. In welding, deliver the first few blows uprightly on each side, then weld the edges of the scarfs with the ball of the hammer. A few careful experiments with these scarfs will show what is required, and with practice no more labor will be needed than is required for the previous eye. The finished product will be more substantial and presentable.
Fig 98.—D, a Ship-smith Eye; E,
a Solid Forged Eye.
D, [Fig. 98], is generally called a ship-smith eye, because it is commonly used in ship work where strength is essential. Special swages, convex lengthwise, are usually provided for shaping the concave curves where they are formed and welded. The eye should be circular between the places indicated by f in sketch D, and the lines from f to where it is welded should be as nearly straight as possible, to increase the strength.
In estimating the material, take two thirds of the length for a ring of the required diameter, and add to that the proper allowance for the stock which forms the portion from f to the weld, and also an amount sufficient for the scarf. This scarf is drawn similar to the one for the welded eye in [Fig. 96], but it should be made convex through its smallest dimension with a top fuller, whose diameter is equal to that of the metal. This is done while the metal is held in a bottom swage of corresponding size. When the scarf is finished, bend the eye into shape and bring the scarf close up to the stem of the eye.
Heat and weld with swages; if convex swages are not obtainable, others may be used by taking care to prevent marring the curves. This eye may also be welded with a large fuller while it is held over the horn of the anvil. If the curves are severely marred, the strength of the eye is lessened.
A solid forged eye is shown at E. When eyes like this are drop-forged in special dies, as they generally are, they do not require much skill, but when made entirely by hand they require considerable experience.
In forging an eye of this kind, the volume of material needed must first be determined, making some extra allowance for the usual waste. A convenient size of material should then be selected (round is preferable) and the amount required for the eye marked off. The round stem should be drawn down to size and the part for the eye forged to a spherical shape, then flattened, punched, and enlarged to correct dimensions.
110. Calipers.—The calipers shown in [Fig. 99] may be easily made from the dimensions given; 3⁄4 × 1⁄8-inch stock should be used for the main piece, and 1⁄2 × 1⁄8-inch stock for the legs.
111. Stock Calculation for Bending.—In the expansion and contraction of metals during the operation of bending, there is a fixed line, where the metal is left undisturbed; in other words, where it is not increased or decreased in length. So all measurements taken to determine the length of material required for producing any bent shapes should be taken from that fixed or undisturbed location, in order to attain accurate results.