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# What do we know about a metric carving?

the Carving happen different: art where drawing is cut out on material, or machine-building which represents the spiral screw cutting executed on a round core or in an opening.

About one such carving from a set of their versions applied in mechanical engineering and life will be narrated by this article.

A carving - it is similar to a wheel, and accompanies us continually. Where we turned the eye, we are surrounded by carvings. They are in furniture, locks, doors, food processors, in some ware, in a bathroom, in a toilet, in any lamp and so on...

Carvings happen: right, left, triangular, round, trapetsiodalny, trapetsiodalny persistent, rectangular, tape, pipe cylindrical, pipe conic, modular, pitchevy. In life we are surrounded by a set of kinds of carvings: tape - on self-tapping screws, round - on socles of bulbs, trapetsiodalny - in power mechanisms, triangular - literally everywhere, beginning from kitchen and finishing with the car in which their tens standard sizes.

The most widespread fixing carving in life is the carving metric, having a triangular profile.

Such carving has a profile corner sixty degrees. A unit of measure of parameters of a carving - millimeter. Designation of such carving consists of the letter “ M “ and figures. For example, M10 means - a carving metric with a diameter of a core of a carving, equal 10 mm.

If the sign " is added to such designation; x “ with figure, following the sign “ x “ the figure designated a carving step. For example, M10 x 1 means - a carving metric with a diameter of 10 mm, having a step carvings of 1 mm. Big strides do not designate - they are the main. The step of a carving is measured by distance between tops of two next rounds. Apply the special templates called by rezbomer to measurement of a step.

In life near at hand it can not appear a rezbomer. In such cases it is possible to measure a carving step by means of a caliper, or, at worst, rulers. It is better to perform measurement of a step on a bolt carving, than nuts. It is connected with openness of a carving and a possibility of direct visual control when carrying out measurements. For measurement it is necessary to count the greatest number of threads and to measure distance between extreme tops of rounds of a carving in a straight line. I prefer numbers: 3, 5, 10. It is connected with simplicity of calculations. For example, the distance between ten rounds of a carving of diameter of 16 mm which made 20 mm was measured. To learn a carving step, it is necessary to divide 20 mm into 10 rounds. Let`s receive a step of a carving, equal 2 mm.

For what it is necessary to know a carving step? Naturally, for correctness of the choice of the thread-cutting tool or a drill for drilling of an opening under a carving.

Determination of diameter of a core is made more simply, than an opredeleleniye of diameter of an opening under cutting of a carving. Diameter of a core is usually equal to diameter of a carving. However, as when cutting a carving there is a metal pulling (increase in initial diameter when cutting a carving), usually diameter of a core is underestimated from nominal rate on 1:5; 1:8 steps of a carving. For example, with a step of equal 2 mm it is preferable to cutting of a carving of M16 that diameter of a core was in limits: from 16 - 2:5=15,6 mm to 16 - 2:8=15,8 mm.

How to learn diameter of an opening under the cut metric carving if near at hand there is no machine-building reference book with tables of standard sizes of a carving and the recommended diameters of openings?

In that case we will use the acquired skills of measurement of a step of future carving and we will calculate diameter of an opening under cutting of a carving a tap.

So, we measured a carving step and calculated - it is equal to 2 mm. We measured diameter of a carving earlier and we know that it is equal to 16 mm. For determination of diameter of an opening the step of a carving of 2 mm is enough to subtract from diameter of a carving of a bolt 16 mm. The result of subtraction will be equal to 14 mm. Means, diameter of an opening under cutting of a carving of M16 with a step of 2 mm has to be equal to 14 mm.

Here such it is a carving metric. Naturally, it is possible to tell about it much more, than it is told in this article.

I Hope that these data will be useful to people who want to master the simplest types of repair, sometimes so necessary in life.]