49, which are transverse sections of _D_, Fig. 50, on the line _f_. The
edges of _D_, in Fig. 48, are simply rounded. There are no rules for
such rounding--only good judgment and an eye for what looks well. The
edges of _D_ as shown in Fig. 49 are more on the beveled order. In
smoothing and polishing such edges, an ordinary jeweler's steel burnish
can be used.

[Illustration: Fig. 50]


SMOOTHING AND POLISHING.

The idea in smoothing and polishing such edges is to get a fair gloss
without much attention to perfect form, inasmuch as it is the flat
surface _d_ on top which produces the impression of fine finish. If this
is flat and brilliant, the rounded edges, like _g c_ can really have
quite an inferior polish and still look well. For producing the flat
polish on the upper surface of the regulator bar _B_ and spring _D_, the
flat surface _d_, Figs. 48, 49, 51 and 52, we must attach the regulator
bar to a plate of heavy brass, as shown at Fig. 47, where _A_ represents
the brass plate, and _B_ the regulator bar, arranged for grinding and
polishing flat.

[Illustration: Fig. 51]

[Illustration: Fig. 52]

For attaching the regulator bar _B_ to the brass plate _A_, a good plan
is to cement it fast with lathe wax; but a better plan is to make the
plate _A_ of heavy sheet iron, something about 1/8" thick, and secure