1.5. Technology of service, tool and equipment of a workplace
There are several techniques of performing procedures of maintenance and car repairs on which the reader will find references in the text of the present manual. Following to the offered instructions will make work of the amateur mechanic of more effective, will allow to organize in the best way and to qualitatively perform various technical procedures and will be the key to full-measured performance of all necessary works.Fixture - the general information
Fixture are called nuts, bolts, hairpins and screws serving for connection among themselves of two or more details. During the work with elements of fixture it is necessary to remember some things constantly. Practically in any carving fixture this or that type of the kontryashchy and stopping devices is applied. It can be lock washers, lock-nuts, lock tags or the special fixing sealant for threaded connections. All used fixture has to be absolutely pure and direct, with an undisturbed carving and not rounded corners of turnkey six-sided heads. It is necessary to take for the rule without fail to make replacement of the damaged fixture elements. Special самоконтрящиеся nuts with nylon or fiber inserts are not subject to reuse as at an otdavaniye lose the kontryashchy properties and at assembly always have to be replaced.
The "stuck" fixture for the purpose of simplification of unscrewing and in order to avoid damages before an otdavaniye has to be processed by the special getting structure. Many mechanics prefer to use turpentine which is convenient for putting from a special small canister with a long nose for this purpose. After wetting of fixture by the getting structure, it is necessary to give to means within several minutes properly to impregnate the oxidized contact layer. Strongly rusted fixture can be cut down by a chisel, is cut by a hacksaw or removed by means of a special gaykolom.
When cutting a head of a bolt or oblamyvaniya of a hairpin on assembly the rest of a carving part can be drilled or taken by means of a special extractor. Most auto repair shops can undertake performance by this, as well as others (for example, restoration of the stripped thread in carving openings), repair procedures.
Flat and lock washers at assembly have to be established always into place in the original provisions. The damaged washers are subject to replacement without fail. Between a lock washer and a soft metal surface (for example, aluminum), thin sheet metal or plastic of the fixed detail it is always necessary to establish flat washers.
Sizes and classes of durability of fixture
For many reasons manufacturers of cars use metric fixture more and more widely. However, it is important to know a difference between this (more universal) fixture and the SAE standard fixture used sometimes (or American). Despite external similarity, elements of these two types of fixture are not interchangeable.
All bolts as SAE standard, and metric, are classified by diameter, a step of a carving and length. For example, the bolt of the SAE 1/2 standard - 13 x 1 has a half of inch in the diameter, 13 rounds of a carving on one inch and length of 1 inch.
Sizes/marking of a class of durability of standard (SAE and USS) bolts
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G - marking of a class of durability |
The metric bolt of M12 — 1.75 x 25 has diameter of 12 mm, a carving step (distance between the next rounds) 1.75 mm and length of 25 mm.
Sizes/marking of a class of durability of metric bolts