If the
pieces are at all irregular in shape, the motions should be gone through
with before the metal is heated and the best positions on the anvil as well
as in the fire determined with regard to the convenience of the workman and
speed of handling the work after being brought to a welding temperature.
Unnatural positions at the anvil should be avoided as good work is most
difficult of performance under these conditions.
_Scarfing._--While there are many forms of welds, depending on the
relative shape of the pieces to be joined, the portions that are to meet
and form one piece are always shaped in the same general way, this shape
being called a "scarf." The end of a piece of work, when scarfed, is
tapered off on one side so that the extremity comes to a rather sharp edge.
The other side of the piece is left flat and a continuation in the same
straight plane with its side of the whole piece of work. The end is then in
the form of a bevel or mitre joint (Figure 50).
[Illustration: Figure 50.--Scarfing Ends of Work Ready for Welding]
Scarfing may be produced in any one of several ways. The usual method is to
bring the ends to a forging heat, at which time they are upset to give a
larger body of metal at the ends to be joined. This body of metal is then
hammered down to the taper on one side, the length of the tapered portion
being about one and a half times the thickness of the whole piece being
handled.
Pages:
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176