1、A-A-52024 66 9999974 0060445 2 A-A-52024 March 12, 1991 COMMERCIAL ITEM DESCRIPTION COMPASSES, MAGNETIC: SURVEYORS AND TRANSIT, POCKET; WITH OPTIONAL BALL AND SOCKET JOINT OR BALL AND SOCKET HEAD, AND JACOBS STAFF The General Services Administration has authorized the use of this commercial item des
2、cription in preference to Federal Specification GG-C-560D. This description covers two types of magnetic compasses, and includes the optional ball and socket joint, or ball and socket head, and Jacobs staff. Type I compasses are intended for use in topographical surveying field work done by the U.S.
3、 Forest Service. Type II compasses are used in geology and survey reconnaissance. General salient characteristics. Desim: The compasses shall consist of a compass box, clinometer, magnetic needle, circular level vial, mechanism to permit declination adjustment, front and rear sights, graduated circl
4、es and scales, and when specified herein, a Jacobs staff, ball and socket joint, or ball and socket head and a carrying case. Classification. Magnetic compasses covered by this specification shall be the following types, classes, and styles as specified: Type I - Surveyors magnetic compass using bal
5、l and socket Type II - Magnetic compass (pocket transit) using ball and socket joint. head. Beneficial comments recommendations, additions, deletions clarifications, etc. and other data which may improve this document should be sent by letter to: U.S. Army Belvoir Research, Development and Engineeri
6、ng Center, ATTN: STRBE-TSE, Fort Belvoir, VA. AMSC N/A FSC 6675 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Licensed by Information Handling ServicesA-A- 52024 Class 1 - O to 90 degree quadrant dial. Class 2 - O to 360 degree circle dial. Style A - Style B - Wit
7、h ball and socket joint, or ball and socket head, Jacobs staff. Without ball and socket joint, or ball and socket head, and without Jacobs staff. Dial Markinq. Class 1 and class 2 compass dials shall be graduated in 1 degree increments. mark. Every tenth degree shall be numbered (i.e., 10, 20, etc.)
8、. Every increment shall be marked with a tick Class 1 Class 2 Material : Class 1 compass dials shall be divided into 90 degree quadrants. The zero degree graduation shall be in the North and South directions. shall be in the East and West directions. The 90 degree graduation Class 2 compass dials sh
9、all be graduated in a complete circle. The zero degree graduation shall be in the North direction, the 90 degree graduation shall be in the East direction, and the 180 degree graduation shall be in the South direction. Metal. The metal, except that of the needle, shall be nonferrous and corrosion re
10、sistant. Needles shall be plated or otherwise durably coated to render them corrosion resistant. Compass box. The compass box shall be a non-magnetic material and shall have a transparent window affording full visibility of the azimuth scale, the clinometer level vial scale and index, and the compas
11、s level vial. The compass box shall have an external screw driver-type adjustment so that the azimuth scale can be rotated with respect to the index. Mametic needle. The magnetic needle shall have magnets permanently attached or shall be magnetized to be sensitive to the earths magnetic field, The n
12、eedle shall be designed and constructed to assure long retention of magnetism and shall indicate magnetic North when the box is rotated 360 degrees. shall be freely supported on a pivot of nonmagnetic hardened material that provides minimum friction. The needle shall be designed in such a manner as
13、to permit use or be provided with a balance weight which can be moved readily to any position and on either end to assure correct balance in any latitude between 85 degrees North magnetic latitude and 65 degrees South magnetic latitude. The needle shall be self-aligning to accurately indicate direct
14、ion of magnetic North and shall be marked to readily indicate North. The ends of the needle shall be tapered to a fine point or The needle 2 Licensed by Information Handling ServicesA-A- 52024 marked so that 0.50 degrees can be estimated. apparent difference in the reading of the ends of the needle.
15、 needle shall be equipped with a lift mechanism to secure it when not in use. The damping time of the needle shall not exceed 15 seconds when the needle is deflected. There shall be no The Jacobs staff. The Jacobs staff shall be a hardwood or nonferrous metal staff, not less than 54 inches long, thr
16、eaded 0.625-11 UNC-2A for a type I compass and 0.25-20 UNC-2A for type II compass to mate with the female end of the ball and socket joint or ball and socket head. metal shoe for penetrating the ground. orcollapsible and shall weigh not more than 4 pounds. The other end of the staff shall be equippe
17、d with a pointed The staff shall be one piece Ball and socket ioint or ball and socket head. A ball and socket joint or ball and socket head to attach the compass to the Jacobs staff shall be constructed to permit tilting the compass through 90 degrees from the horizontal to the vertical plane and a
18、lso permit full rotation of the compass in azimuth through 360 degrees. The ball joint shall be equipped with a knurled collar to tighten the joint in tilted position and a knurled thumbscrew to tighten the joint in the azimuth position. The male end of the ball joint shall be threaded 0.50-20 UNF-2
19、A to mate with that in the compass base female recessed fitting, which shall be at least 0.250-inch deep for a type I compass and the type II compass shall be furnished with a bracket to attach the compass to the ball joint. The other end of the ball joint shall be threaded 0.625-11 UNC-2B for a typ
20、e I compass and 0.250-20 UNC-2B for type II compass to fit the Jacobs staff. Carrying case. When required, a sewed leather case with a sling strap shall be provided to hold the compass. carrying case shall be of case leather, mildew resistant treated, grain side smooth with the sides of the case for
21、med. A hold down strap and a nonferrous metal fastening stud shall be provided for the closing flap. When applicable, the Tolerances. The tolerances for the beveled knurled revolving ring, compass dial, and raised compass ring shall be A10 minutes per degree graduation, with no more than I30 minutes
22、 per quadrant. error shall be noncumulative over the entire circle. The Specific salient characteristics. Type I. surveyors magnetic compass usinn ball and socket ioint. Beveled knurled revolvina ring. The beveled, knurled revolving ring shall be aluminum and shall be graduated in single degrees bot
23、h ways from zero in four 90-degree quadrants, with a sighting mark at each quadrant. 3 Licensed by Information Handling Services - A-A-52024 66 9939974 0060448 = A-A- 52024 Compass dial. The compass dial shall be marked to indicate the four cardinal compass points. East and west points shall be tran
24、sposed 180 degrees from normal map positions. A clinometer scale for reading vertical angles shall be graduated in 1-degree increments for 180 degrees, and numbered every 10 degrees in both directions from zero to 90 degrees. with the west cardinal point on the compass dial. The zero point shall coi
25、ncide Raised compass rinq. The raised compass ring shall be graduated in single degrees and numbered every 10 degrees in both directions from zero to four 90-degree quadrants. provided to adjust the azimuth of the raised compass reading for declination. The mechanism shall be enclosed within the com
26、pass box except for the operating pinion, which shall extend through to the outside of the compass box terminating in a slotted screwhead to facilitate the adjustment from outside the compass box. The mechanism shall be nonmagnetic, corrosion-resistant metal and shall be constructed in such a manner
27、 that dust or moisture cannot enter the compass box where the adjustment screw terminated. fixed index pointer shall be permanently secured to the inside wall of the compass box and shall extend over the raised compass ring to serve as a reference point for adjusting the raised compass ring. The ind
28、ex pointer shall coincide with the north point of the compass dial. A mechanism shall be A Pendulum clinometer. A clinometer pendulum shall be enclosed in the compass box for reading vertical angles when the compass is placed vertically on its edge on a level surface. The pendulum shall swing freely
29、 from an axis concentric with the pivot of the compass needle. The vertical angle shall be indicated by the position of the pendulum against the clinometer scale on the compass dial. Spirit level. A circular hermetically sealed spirit level for leveling the compass shall be located and secured to th
30、e inside of the compass box. inscriptions. The level shall not cover any essential Compass box. The compass box shall not be more than 4 inches in diameter. Magnetic needle. The magnetic needle shall be not less than 3 inches long and shall be equipped with a stop and a jewel setting. Folding sights
31、. Two folding sights shall be secured to the compass box by not less than two screws for each sight. The sights shall be hard forged brass or bronze and shall be constructed to permit their being raised to a vertical position for sighting objects or to be folded down flatover the compass glass when
32、not in use. When in the vertical sighting position, the sights shall project 4 Licensed by Information Handling Services- e? A-A-52024 bb = 9999974 00b0449 T A-A- 52024 above the revolving ring on top of the compass box to a distance equal to the diameter of the revolving ring. sights shall be posit
33、ioned in the north-south axis of the compass dial and also to the centerline of the base parallel to two of the beveled edges of the base. The rear (south) folding sight shall have a narrow vertical peep slot centered in the sight. length of the slot shall be 75 percent of the total length of the si
34、ght. The rear sight shall be located on the south end of the compass box and in line with the north-south axis. (north) sight shall have a wider slot, 50 percent of the width of the sight, equipped with a vertical sighting line from 0.010 to 0.015 inch wide running the length of the slot. shall be c
35、entered on the north-south axis of the compass dial at the north end of the compass box. The center of the The The front The line and slot Compass base, A 4.50 by 4.50-inch aluminum, nickel, silver, or other non-magnetic material base shall be secured to the compass box by not less than four counter
36、sunk screws with the compass box positioned in the center of the base. the base and compass box, in azimuth, shall be that the flat-sides of the base shall be parallel to the north-south and east-west axes of the compass dial, The base shall be smooth and flat on the bottom to permit close and accur
37、ate positioning on a flat surface, adjustment devices and fittings. An internal fitting threaded 0.50-20 UNF-2B, shall be provided in the base to accommodate the male end of the ball and socket join to ball and socket head. fitting shall not permit dust or moisture to enter the compass box. The base
38、 shall have four beveled and graduated edges. Two adjacent edges shall be graduated in 0.50 degree increments, +30 seconds, through 90 degrees and numbered every 10 degrees up to 80 degrees in both directions. intersecting corner of the two adjacent edges. Another edge shall be graduated in 0.125-in
39、ch increments, f0.0156-inch and numbered every 1 inch. increments, ITO.01-inch, and numbered every 1 inch. The relative position of The base shall have cut away or recessed space for screw The The 45-degree mark shall be at the The other edge shall be graduated in 0.10-inch Specific salient characte
40、ristics: Tpe II, magnetic compass (pocket transit) using ball and socket head. Compass dial. The compass dial shall be graduated in l-degree increments and numbered every graduated 10 degrees. Declination of adiustment. A mechanism shall be provided to adjust the position of the azimuth of the compa
41、ss dial not less than 50 degrees in either direction. 5 Licensed by Information Handling Services A-A-52024 66 9999974 0060450 6 - A-A- 52024 Index pointer. An index pointer shall be permanently secured to the inside wall of the compass box and shall extend over the compass dial. The index pointer s
42、hall be in line with the front sight and shall coincide with the north point of the compass. Clinometer. The clinometer shall consist of a tubular vial, a clinometer scale and a vernier index mounted on the compass box in such a manner that the clinometer may be rotated by an external leveler. The c
43、linometer shall have its zero at the West cardinal point. Graduations shall extend on both sides of the zero and shall be in degree and percent declination. The degree scale shall be graduated every 1 degree, f.50 degree, shall extend 90 degrees on each side of zero, and shall be numbered every 10 d
44、egrees. The vernier shall permit reading to 5 minutes. The percent scale shall extend 100 percent in both directions. Graduations shall be by 5 percent increments. Each 20 percent graduation shall be numbered. Spirit level. A circular hermetically sealed spirit level shall be secured to the inside o
45、f the compass box in the Southeast or Northeast quadrant. The level shall not cover any essential inscriptions. Dimensions and weights. The closed compass shall be not more than 4 by 4 inches, with rounded corners, by not more than 1.375 inches thick. The compass with carrying case shall weigh not m
46、ore than 10 ounces. Magnetic needle. The magnetic needle shall be between 2.000 and 2.250 inches long, with jeweled center and a stop. Mirror and cover. A mirror shall be bonded or otherwise mounted on a hinged cover attached to the south end of the compass box. The cover and the mirror shall provid
47、e a 0.375 by 0.4687-inch clear glass window, an engraved center-line which will serve as an alternate front sight, and a folding front sight tip. Hinge friction shall be such as to permit setting of the mirror at any angle between full-closed and full-open position of the cover. Hinge stops shall be
48、 provided at 180 degrees open position. In the closed position, the cover shall actuate a lifting mechanism in the compass box to lift the magnetic needle from its pivot and hold the needle in place against the compass box window. Cover latch. The cover shall latch into the closed position by use of
49、 a spring detent or closely controlled mechanical interference. The cover shall open by use of fingergrips (either natural or machined in) or by use of a push-to-open plunger-type spring release. When no mechanical opening aid is provided, fingergrips will be provided on the exterior of the cover and compass box. 6 Licensed by Information Handling ServicesA-A-52024 66 E 9999974 00604511 8 E A-A-52024 North sight. The sight attached to the north end of the compass box shall fold through 180 degrees +10 degrees with a tip that folds 60 degrees f7 degrees upward from o
