t all marks of the
graver be thoroughly removed, because if any grooves, no matter how
small, are left, they act as minute capillary tubes to convey the oil.

If the hole jewel be of the proper shape, the end-stone not too far from
the hole jewel and too much oil is not applied at one time, the oil will
not spread nor run down the staff, but a small portion will be retained
at the acting surface of pivot and jewel, and this supply will be
gradually fed to these parts from the reservoir between the jewel and
end-stone, by the action of capillarity.

Having examined into the requirements of the pivot and its jewel and
having gained an insight into what their forms should be, we are the
better able to perform that portion of the work in an intelligent
manner.

CHAPTER III.

Our wire has been roughed out into the form of a staff, has been hardened
and the temper drawn down to the requisite hardness and we are now ready
to proceed with our work. As I said before, we have now arrived at a
point where many authorities differ, _i. e._, as to whether the finishing
of the staff proper, should be performed while the work is held in the
chuck, or whether a wax chuck be substituted. We will take it for granted
that you have a true chuck and that you prefer to finish all the lower
portion of the staff while held in the chuck.

Before we proceed with our work it will be necessary for us to make some
accurate measurements, as we cannot afford to do any guess work by
measuring by means of the old staff. I have used a number of different
kinds of calipers and measuring instruments for determining the various
measurements for a balance staff, but have met with more success with a
very simple little tool which I made myself from drawings and description
published some years ago in THE AMERICAN JEWELER. This simple little tool
is shown in Fig. 7, and has been of great service to me. It consists of a
brass sleeve A, with a projection at one end as shown at B. This sleeve
is threaded, and into it is fitted the screw part C, which terminates in
a pivot D, which is small enough to enter the smallest jewel. The sleeve
I made from a solid piece of brass, turning it down in my lathe and
finishing the projection by means of a file. The hole was then drilled
and threaded with a standard thread. The screw part C, I made of steel
and polished carefully.

[Illustration: _Fig. 7._]

To ascertain the proper height for the roller, place it