Forge Work

by William L. Ilgen

Fig. 96.—Eye or Ring Bolts.
A, an open eye; B, a welded eye.

B is a welded eye. It is made by forming first a flat, pointed scarf on the end of the bar and bending it through its smallest diameter where the drawing was begun. This bend should be no less than 70 degrees on the outer side. Determine the length of the material needed for forming a ring of the required diameter, then subtract the diameter of the material from the determined length. Using this result, place a center-punch mark f that distance from e, and bend the piece at f in the same direction as e.

Form the metal between the bends into a circle, and place the scarf in position for welding, as at B. During the heating for welding, if the circle heats more rapidly than desired, it should be cooled off and the heating then continued. The welding should be done as quickly as possible and swaged if required.

The eye bolt, shown in [Fig. 97], is similar to a solid forged eye. It is formed and welded with a specially forged scarf called a butterfly scarf.

Determine the amount of material needed to form a ring of the required diameter, and add to that a sufficient allowance for upsetting and welding, which would be approximately equal to the diameter of the material used. An invariable rule for that allowance cannot be given, because the results of the upsetting are seldom the same.

Place a center-punch mark the estimated distance from one end of the bar; then upset the end ¹⁄₈ inch larger than its original diameter, next upset it at the mark to a similar dimension, and bend it there to an angle of no less than 70 degrees. Now with the bend lying flat on the face of the anvil, draw out a thin, narrow scarf with a small ball peen hammer, not any wider than the thickness of the metal. The scarf may be drawn also by holding the outer portion of the bend on a sharp corner of the anvil and by drawing with overhanging blows. This scarf is shown in the upper view of [Fig. 97] as it should appear.

Fig. 97.—Eye Bolt made with a Butterfly Scarf.

The butterfly scarf should now be formed on the opposite side from the one just finished, by holding each side of the end at an angle of about 45 degrees on the edge of the anvil; this scarf may be drawn with overhanging blows. The extreme end should also be drawn thin in a similar manner, while it is held at a right angle with the edge of the anvil. All outer edges of this scarf should be thin and sharp.