In practice 8 threads per inch has been found to give good satisfaction.
e. In addition to a tightly fitting nut, some reliable device must be provided, in both steam and water ends, for absolutely preventing these nuts from working off.
Fig. 6.
[Fig. 6] shows one form of such a locking device and illustrates the kind of security desired.
This device combines the advantage of a taper key and a split pin, and the elongated key-slot gives sufficient leeway to always insure that the key can be driven up tight against the nut and thus prevent it from even starting to work off. Other methods will be approved in writing, if found satisfactory.
21. Valve Rods.
a. Valve Rods for their entire length must be of solid Tobin Bronze, with sizes not less than in table below.
| Size of Pump. | 500 gal. | 750 gal. | 1,000 gal. | 1,500 gal. |
|---|---|---|---|---|
| Diameter of rod | 1 inch. | 11⁄8 inch. | 11⁄8 inch. | 11⁄4 inch. |