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98 MECHANICAL DENTISTRY AND METALLURGY.

of the stay may, in the first place, be obtained by cutting a
strip from a piece of gold with a pair of plate forceps. The
points upon the stay to be pierced for the admission of the
platinum pins may be ascertained by coating the surface
of the former with wax softened in the flame of a spirit
lamp, and pressing it first against the lower pin, the point
of which will be indicated by an indentation of the wax.
The backing is then perforated at this point with a plate
punch. The strip is then reapplied to the upper pin, and
the second hole obtained in like manner as the first. In-
stead of using wax, the ends of the rivets may be stained
with some pigment, which will show the points to be pierced
in the backing.
The backings should be adapted accurately to the back
of the tooth; it is then cut to the proper length, reaching
nearly or quite to the point, and shaped with a file to the
general form of the crown. When the stays are to be
united they should be formed with a shoulder at a point
corresponding with the neck of the tooth, and the proxi-
mate edges below united closely. The process of soldering
will be greatly facilitated and the piece will be more easily
and artistically finished by securing, in the first instance,
a perfect coaptation of all the parts which are ultimately
to be united. The sides of the holes in the backings facing
the plate should now be enlarged or countersunk with a
spear-shaped or conical bur drill, and when applied to the
teeth the projecting ends of the platinum pins are cut off
even with the backings and then split and spread apart with
a small chisel-shaped instrument. A head will thus be
formed to the rivets, when solder is fused upon them, which
will prevent them from drawing from the linings.
The Soldering Process.—All the lines of union between
the several pieces should next be well scraped, exposing a
clean, bright, metallic surface to the solder; the seams are