DLA A-A-59221-1998 LAPPERS POPPET VALVE HAND POWERED [Superseded NAVY MIL-L-18947 B CANC NOTICE 3 NAVY MIL-L-18947 B VALID NOTICE 2 NAVY MIL-L-18947 B VALID NOTICE 1 NAVY MIL-L-189.pdf
《DLA A-A-59221-1998 LAPPERS POPPET VALVE HAND POWERED [Superseded NAVY MIL-L-18947 B CANC NOTICE 3 NAVY MIL-L-18947 B VALID NOTICE 2 NAVY MIL-L-18947 B VALID NOTICE 1 NAVY MIL-L-189.pdf》由会员分享,可在线阅读,更多相关《DLA A-A-59221-1998 LAPPERS POPPET VALVE HAND POWERED [Superseded NAVY MIL-L-18947 B CANC NOTICE 3 NAVY MIL-L-18947 B VALID NOTICE 2 NAVY MIL-L-18947 B VALID NOTICE 1 NAVY MIL-L-189.pdf(6页珍藏版)》请在麦多课文档分享上搜索。
1、A - A-5 7 2 2 I 70118054 0000313 T77 INCH-POUND A-A-5922 1 Mav 18. 1998 SUPERSEDING 24 August 1964 MIL-L-18947B COMMERCIAL ITEM DESCRIPTION LAPPERS, POPPET VALVE, HAND POWERED The General Services Administration has authorized the use of this commercial item description by all Federal agencies. 1. S
2、COPE, This commercial item description (CID) covers grade A and grade B hand-powered lappers of the oscillating, progressively or irregularly advancing type used primarily for lapping automotive engine valves and seats. 2. CLASSIFICATION. Lappers shall be of the following grades (see 7.2): Grade A -
3、 Heavy duty Grade B - Light duty. 3. S“T CHARACTERISTICS. 3.1 Description. Grades A and B lappers are intended for use in maintenance which requires the lapping of valves and valve seats of automobile engines. They are satisfactory for valves and valve seats requiring a normal amount of lapping. Gra
4、des A and B lappers are not recommended for valve and valve seats which are badly pitted, burned, or scored unless the valves and valve seats cannot be replaced with new parts or that power tools are not available. 3.1.1 Grade A lappers. Grade A lappers are considered to be appropriate for use in ma
5、intenance shops which may encounter heavy work loads of valve and valve seat lapping during engine repairs. They are considered to have satisfactory service life of longer duration than grade B. Beneficial comments, recommendations, additions, deletions, clarifications, etc. and any data which may i
6、mprove this document should be sent to: Commanding Officer (Code 15E2), Naval Construction Battalion Center, 1000 23rd Avenue, Port Hueneme, CA 93043-4301, by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. AMSC NIA FSC 5120
7、Licensed by Information Handling Services- A-A-59221 W 9018054 0000314 905 A-A-59221 3.1.2 Grade B lappers. Grade B lappers are considered to be appropriate for intermittent use and are suitable for inclusion in toolboxes for maintenance of automobile engines. 3.2 Standard commercial product. The la
8、ppers shall, as a minimum, be in accordance with the requirements of this commercial item description and shall be the manufacturers standard commercial product. Additional or better features which are not specifically prohibited by this commercial item description but which are a part of the manufa
9、cturers standard commercial product, shall be included in the lappers being furnished. A standard commercial product is a product which has been sold or is being currently offered for sale on the commercial market through advertisements or manufacturers catalogs, or brochures, and represents the lat
10、est production model. 3.3 Material. The housing of the lapper shall be cast iron or drawn steel. 3.4 Design and construction. The lapper shall consist essentially of a housing, crank arm, valve lifting spring, extension drive stem, drive points, gear train or mechanism, ball thrust bearing and rubbe
11、r suction cups. The lapper shall produce an oscillation of the valve around its axis with progressive or irregular advancement. Lappers shall be so constructed that no assembled part will became detached during normal use. All moving parts shall operate without binding or looseness that would impede
12、 proper knction of tool. 3.4.1 Grade A. Grade A lappers shall be heavy-duty capable of withstanding 500,000 revolutions without permanent deformation when operated at 200 revolutions per minute with a torque load between 2 to 3 inch pounds (0.23 to 0.34 newton metre (Nm) to the drive stem. 3.4.2 Gra
13、de B. Grade B lappers shall be light-duty capable of withstanding 90,000 revolutions without permanent deformation when operated at 200 revolutions per minute with a torque load between 2 to 3 inch pounds (0.23 to 0.34 N-m) to the drive stem. 3.4.3 Housing. The housing shall be of two half sections
14、or one section with a cover. In either case, the half sections or cover plate shall be assembled securely to minimize both the loss of light density grease and the entrance of foreign particles. The assembly shall allow ready access for lubrication and removal and replacing of parts. The housing sha
15、ll properly support the enclosed mechanism. A handle or knob, which affords a comfortable grip, shall be attached or integral with the top side of the housing. 3.4.4 Crank arm. The crank arm shall be of a length and shape to ensure clearance for hands in operating, and have sufficient strength to wi
16、thstand intended usage. One end of the crank arm shall provide means for attaching to crank shaft. The other end of the arm shall have a handle (knob) affixed to rotate on a bolt, rivet or pin of the head and shoulder type. r 3.4.5 Valve lifting spring. The lifting spring shall be helical, or hard d
17、rawn spring wire, oil- tempered wire or piano wire. The spring shall be 2.25 10.12 inches (57 f 3 millimetre (mm) long by 1.0 5 0.06 inches (25 k 2 mm) in diameter. The helical string may be straight-wound or the ends may be conical in shape. 2 Licensed by Information Handling Servicesz . A-A-59221
18、= 9018054 0000315 841 A-A-5922 1 3.4.6 Extension drive stems. Each lapper shall be furnished with a long drive stem not ess than 7 inches (178 mm) long and not greater than 8 inches (203 mm) long. Each lapper shall also have a short drive stem not less than 3 inches (76 mm) long, and not greater tha
19、n 4 inches long (102 mm). One end of the drive stem shall be threaded for attachment to the driving spindle. The opposite end of the drive stem shall be slotted and drilled for attachment of drive points. 3.4.7 Drive points. Drive points, in the amount and sizes normally furnished by the manufacture
20、r, shall be included with the lapper. The points may be either one-piece universal blade type or individual units and shall contain a hole to allow for attachment to the stem with a cotter pin. When specified (see 7.2), special drive points shall be supplied. 3.4.8 Gear train or mechanism. Gears and
21、 pinions, if applicable, shall be secured to crank and drive shafls by a positive means to ensure proper alignment, rotation and meshing. In the grade A lapper, the relation between the spacing and number of teeth of the driving and driven gears or the capability of the operating mechanism shall be
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