od _F_. We show
separate at Figs. 113 and 114 the slide _G N_ on an enlarged scale from
Fig. 109. Fig. 114 is a view of Fig. 113 seen in the direction of the
arrow _e_. All joints and movable parts should work free, in order that
the center _I_ may be readily and accurately set. The parts _H F_ are
shown separate and enlarged at Figs. 115 and 116. The piece _H_ can be
made of thick sheet brass securely attached to _F_ in such a way as to
bring the V-shaped groove at right angles to the axis of the rod _F_. It
is well to make the rod _F_ about 1/8" in diameter, while the sliding
center _I_ need not be more than 1/16" in diameter. The cone point _n_
should be hardened to a spring temper and turned to a true cone in an
accurately running wire chuck.

[Illustration: Fig. 115]

[Illustration: Fig. 116]

The hollow cone end _m_ of _I_ should also be hardened, but this is best
done after the hollow cone is turned in. The hardening of both ends
should only be at the tips. The sliding center _I_ can be held in the
V-shaped groove by two light friction springs, as indicated at the
dotted lines _s s_, Fig. 115, or a flat plate of No. 24 or 25 sheet
brass of the size of _H_ can be employed, as shown at Figs. 116 and 117,
where _o_ represents the plate of No. 24 brass, _p p_ the small screws
attaching the plate _o_ to _H_, and _k_ a clamping screw to fasten _I_
in position. It will be found that the two light springs _s s_, Fig. 115
will be the most satisfactory. The wire legs, shown at _L_, will aid in
making the device set steady. The pillar _E_ is provided with the same
slides and other parts as described and illustrated as attached to _D_.
The position of the pillars _D_ and _E_ are indicated at Fig. 110.

[Illustration: Fig. 117]

[Illustration: Fig. 118]

We will next tell how to flatten _F_ to keep _H_ exactly vertical. To
aid in explanation, we will show (enlarged) at Fig. 118 the bar _F_
shown in Fig. 109. In flattening such pieces to prevent turning, we
should cut away about two-fifths, as shown at Fig. 119, which is an end
view of Fig. 118 seen in the direction of the arrow _c_. In such
flattening we should not only cut away two-fifths at one end, but we
must preserve this proportion from end to end. To aid in this operation
we make a fixed gage of sheet metal, shaped as shown at _I_, Fig. 120.

[Illustration: Fig. 119]

ESCAPEMENT MATCHING DEVICE DESCRIBED.

[Illustration: Fig. 120]

In practical construct