b. The net area of valve-rod at its smallest section subject to tensile stress, must not be smaller than at bottom of U. S. standard screw thread on rod of diameter given above.
The construction of this rod as affecting lost motion at slide valve is specified under Article 15.
22. Stuffing Boxes.
Fig. 7.
a. All six stuffing boxes must be bushed at the bottom with a brass ring with suitable neck and flange, and the follower or gland must be either of solid brass, or be lined with a brass shell 3⁄16-inch thick, having a flange next the packing, as shown in the sketch.
The bottom of stuffing boxes and the end of glands should taper slightly towards the center as per sketch.
b. These glands should be strong enough to withstand considerable abuse, so as not to break from the unfair treatment of unskilled men.
23. Pressure Gauge.
a. A pressure gauge of the Lane double tube spring pattern with 5 inch case must be provided and attached to the steam chest inside the throttle valve.