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. Each piece should be given this shape before proceeding farther.

The scarf may be produced by filing, sawing or chiseling the ends, although
this is not good practice because it is then impossible to give the desired
upset and additional metal for the weld. This added thickness is called for
by the fact that the metal burns away to a certain extent or turns to
scale, which is removed before welding.