MIL-PRF-907F
accuracy. Two carbon steel face places in accordance with ASTM A 109, 13 by 3 inches and 0.125 inch thick with
a surface finish of 62 RHR or smoother and five equally spaced holes to match those of the above described end
blocks, shall be furnished for this test. Components for this test shall be as shown on Figure 1. A torque wrench
shall be used which is easily readable, graduated in foot-pounds (ft-lb) and has a degree of accuracy of ± 5 percent.
The overall length of each stud shall be measured with a dial indicator type device or equal, graduated in 0.0001
inch divisions, having an overall accuracy of ± 0.0001 inch.
4.4.2.1.2 Preparation. Dry-cleaning solvent shall be in accordance with type I of MIL-PRF-680. Each
component shall be cleaned in the dry-cleaning solvent and dried just prior to lubrication. The test equipment shall
be assembled using the two plates as specified in 4.4.2.1.1. The threads of the studs and nuts shall be evenly coated
with the antiseize compound as follows:
a. A liberal quantity of compound shall be applied to the studs and nuts.
b. The nuts shall then be run to the ends of the studs (prior to assembly with the block).
c. The excess compound shall be removed from the ends of nut travel on the studs and from the edges of
the nuts after removal from the studs.
The block and plate shall be assembled with a stud in each of the five holes. The surface of the plates and the
mating surfaces of the nuts shall be coated with a light coating of the antiseize compound. The nuts shall be run on
to the studs, hand tight, against the plates. The overall length of each stud shall be measured to ± 0.0001 inch and
recorded.
4.4.2.1.3 Procedure. The nuts shall be tightened until an elongation of 0.0162 ± 0.0001 inch is obtained,
which corresponds to a stress of approximately 50,000 pounds per square inch (PSI) at the root area of the stud
thread. The torque required for each nut and stud tightening shall be recorded. The test block assembly shall be
placed in an electronically heated oven and subjected to 1050 + 10 - 0°F for 6 hours. Then the assembly shall be
removed from the oven and allowed to cool to room temperature. The breakaway torque to loosen the nuts shall be
measured and recorded. The length of the studs shall be measured. The nuts shall be tightened to re-establish the
elongation of the stud length (that is, 0.0162 ± 0.0001 inch) and the torque required recorded. The heating, cooling,
torque measurements, and stud length measurements shall be repeated. Then for the third time the assembly shall be
heated, cooled and subjected to a spray of 20 percent aqueous solution of sodium chloride for 7 days. At the end of
this period, the assembly shall be removed and allowed to dry at room temperature for 24 hours. The torque
required to loosen the nuts shall be determined and recorded. The condition of the threads and other contact
surfaces, seizing of the nuts and shearing of the studs shall be noted and properly recorded. A five -point check of
the torque wrench calibration against another calibrated wrench at 150 ft-lb shall be made prior to torquing and
untorquing each assembly. If the torque wrench is dropped or otherwise damaged during its use, its calibration shall
be completely rechecked (five points) before further usage. The torque wrench calibration shall be considered
acceptable if the torque reading is within 5 percent of the actual torque.
4.4.2.1.4 Acceptance criteria.
a. No nuts shall seize during this test.
b. There shall be no galling evident on the threads of the nuts or studs, the nut surfaces and the plate surfaces (under
the nut faces). Only one nut per stud need be removed to inspect for galling on threads. Mating surfaces of each nut
and plate shall be inspected after disassembly. No galling is defined as no raised metal on any contacting surfaces as
can be observed with 20-20 vision at 1X magnification within the distance range of ½ to 2 feet.
c. The average breakaway torque for the loosening of the nuts from the five studs shall not exceed 250 ft-lb.
4.4.3 Storage stability. Storage stability shall be in accordance with method 3467 of FED-STD-791 with
the modifications specified herein. Two one-pound cans shall be stored covered in an oven at a temperature of 66 ±
3°C (150 ± 5°C) for 6 months. The sample shall then be examined in accordance with 4.4.2.1 and for presence of
crystalline material. No crystalline material or lumps are acceptable.
4.4.4 Toxicity. The compound shall be evaluated by the Navy Environmental Health Center
(NAVENVIRHLTHCEN) using the administrative Health Hazard Assessment (HHA). A flowchart for this process
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