If such gold metal is employed, after
hammering to obtain the greatest possible elasticity to the spring, the
gold is filed away, except where the spring is acted upon by the
discharging jewel _h_. We have previously mentioned the importance of
avoiding wide, flat contacts between all acting surfaces, like where the
gold spring rests on the horn of the detent at _p_; also where the
detent banks on the banking screw, shown at _G_, Fig. 142. Under this
principle the impact of the face of the discharging jewel with the end
of the gold spring should be confined to as small a surface as is
consistent with what will not produce abrasive action. The gold spring
is shaped as shown at Fig. 142 and loses, in a measure, under the pipe
of the locking jewel, a little more than one-half of the pipe below the
blade of the detent being cut away, as shown in Fig. 143, where the
lines _r r_ show the extent of the part of the pipe which banks against
the banking screw _G_. In this place even, only the curved surface of
the outside of the pipe touches the screw _G_, again avoiding contact of
broad surfaces.
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