(b) Socket end of screw shall be flat and chamfered. The
chamfer shall extend to the minor diameter of the thread and the edge between flat and
chamfer shall be slightly rounded.
(c) Location of effective locking area "X" shall be in accordance with MS
15981 except as noted herein.
(d) PMax. = Maximum point plus minimum of
1 thread pitch. For ease in starting, locking element shall not be effective within this
area.
(e) Maximum major thread diameter plus .010 = Maximum ring gage diameter that locking
region of part must pass through freely or with finger
pressure.
(f) See MS51021 and MS51023 for set screws without self-locking feature.
(g) As MIL-F-18240 doesn't establish torque requirements for items
above heavy
line, only a positive indication of torque is required.
MATERIAL:
Steel corrosion resisting: Federal Standard 66, numbers 302, 303,
304, 316 or equal to or
interchangeable with 16:18 Chromium-Nickel Alloy Steel.
LOCKING
ELEMENT:
In accordance with Specification MIL-F-18240.
DESIGN
AND USAGE
LIMITATIONS: See MS 15981.
TREATMENT: Passivated
(See Procurement Specification).
MAGNETIC
PERMEABILITY: These screws have a magnetic
permeability of 2.0 maximum (air = 1.0) for a field of H = 200
orsteds using a magnetic indicator per MIL-I-17214.
EXAMPLE
OF PART
NUMBER:
MS-18064-57 = ¼-28UNF-3A x 3/4 long
corrosion resisting steel cup point self-locking set
screw.
