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MIL-P-18526A(SH) Rolling contact bearings having
value in excess of 200,000 shall be
oil lubricated unless the manufacturer can demonstrate to the design review agency that the
specific grease lubricated bearing application has been proven in previous Navy shipboard
service.  Grease lubrication is preferred when
is less than 200,000. Where forced feed lubrication is provided for turbine-driven pumps, the
lubricating system shall be in accordance with requirements of the applicable turbine spec-
ification (see 3.5.1).  Lubricants shall be in accordance with the following:  grease shall
conform to DOD-G-24508 and oil shall conform to MIL-L-17331.  Bearings shall be capable of
being relubricated without removing the bearings and shall not require frequent lubrication
if the pump is not operated over an extended period of time. Thrust bearing housings shall be designed so that the thrust bearings will
be adequately lubricated immediately when the shaft starts to turn.  This shall be accom-
plished by properly locating oil supply and drain pipes, and by adequate sealing of the
bearing housings so that an adequate supply of oil will remain in the bearing housings,
3.3.6 Piping and valves.
3.3,6.1 Valves, flanges, fittings, and bolting shall conform to MIL-STD-777 for sur-
face ships and as specified (see 6,2.1) , except tapered pipe threads are acceptable for use
in grease fittings located on nonmoving parts. Gland seal piping/tubing shall be in accordance with category E-1 of MIL-STD-
777.  Related valves/fittings shall be steel in accordance with MIL-T-20157.  Gland seal
piping/tubing shall be sized as required by pump flow rate and all connections and fittings
shall be screw type.
3.3.7 Casings and heads. Casings, also referred to as cylinders, are those parts which enclose the
Bores of the casings shall be parallel to the rotors. Casings shall be fitted with casinq liners, also referred to as rotor housings,
and shall be replaceable wearing parts located between casing bore and rotors.
3.3,7.3 Suction and discharge openings shall be cast integral with the casings or
heads, shall have machined and scraped or ground flange faces in accordance with ANSI B46.1,
and shall be located as specified by NAVSEC or the procuring agency concerned (see 6.2.1). Heads shall have accurately machined faces in accordance with ANSI B46.1,
Joints between casings and heads may be made up either metal-to-metal or with a thin plant
or animal fiber gasket in accordance with HP-P-96 not exceeding 0.010 inch in thickness.
Heads shall be rabbetted or doweled to the casings. Forcing bolts shall be provided in pumps for breaking joints.
3.3.7,6 Clearance shall be provided around bolt heads and nuts to permit the use of
ordinary tools. Fitted bolts or heavy dowel pins shall be provided in flexible-coupled pumps
to insure maintenance of alinement in reassembly.  Tapered dowel pins shall be corrosion-
resistant, shall have a threaded end and nut design, and shall be secured against coming
adrift under shock loading.
3.3.8 Rotors-- and shafts.
-- Rotors shall be accurately machine finished or ground throughout. They shall
be integral with or secured to the shafts by keys.  Rotors shall be secured positively
against lateral displacement on shafts. Shafts shall have a minimum hardness of 275 Brinell. Except where locknuts are used, shaft threading shall be opposite to direction
of rotation.

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