to a TY or, as they are commonly called, sanitary T. A
tapped fitting gets its name because it is tapped for iron pipe
thread. Tapped fittings are used for venting and should not be
used for waste unless the tap enters the fitting at an angle of
45 deg.

These fittings and pipe are joined by first caulking with oakum and
pouring, with one continuous pour, the hub full of molten metal.
When cool, the lead should be set and then caulked around the pipe
and around the hub.

The amount of lead and oakum required for various-sized joints is
as follows:

Pipe size 2 3 4 5 6 8 10 12 15
Pounds of lead 1-1/2 2-1/4 3 3-3/4 4-1/2 6 7-1/2 9 11-1/4
Oakum (ounce) 4 6 8 10 12 16 20 24 30

RUST JOINTS.--The plumber is called upon to run cast-iron pipe in
places where lead and oakum will not be of service for the joints.
In cases of this kind, a rust joint is made. This "rust" is made
according to the following formula:

1 part flour of sulphur.
1 part sal-ammoniac.
98 parts iron borings (free from grease).

This mixture is made the consistency of cement, using water to mix
thoroughly and bring all parts into contact with each other. When
it hardens, it becomes very hard and makes a tight joint which
overcomes the objections to lead and oakum joints.

WROUGHT-IRON AND STEEL PIPE

This pipe comes in about 18-foot lengths and fittings of the
following makes and shapes, and their use is fully explained. The
lengths of pipe come with a thread on each end and a coupling
screwed on one end. The lengths come in bundles up to 1-1/2-inches
and in single lengths over that size. Screw pipe fittings, it will
be noted, are called by a different name than cast-iron ones. The
fittings in common use today are the 90 degree ell, 45, 22, and
16-2/3. The Y and TY, tucker fittings, and inverted Ys are used in
practically the same way as the cast-iron fittings. The 90 degree
ell, 45, 22, and 16-2/3 are used to change the run of pipe that
many degrees. All 90 degree fittings, ells, and Ts are tapped to
give the pipe a pitch of 1/4 inch to the foot. It is better to use
two 45 ells to make a 90 bend when it is possible.

[Illustration: CAST-IRON SCREW FITTINGS
FIG. 54.]

INVERTED Y.--The inverted Y is used in venting to good advantage.
The use of these fittings is illustrated in the sketches.

WASTE PIPES.--Waste pipes are the