# Advice 1: How to use the scale Rappoport

Today the purchase of rings or diamond earrings is not very easy. Not to be mistaken should at least know the price of carat of the diamond, but if the diamond is bought again, even the fancy calculator will not be able to give accurate data on its price. In this case, comes to the aid of the scale Rappoport.

## What is the scale of Rapport

The Rapoport price list, as it is called, the scale Rappoport, is the oldest and quite a popular publication, which is a price indicator for such a beautiful and precious stone like a diamond.

The first edition of this scale was presented in 1978. It is called in honor of its developer, Martin RAPAPORT. Yes, of course, this price list has some flaws, but nonetheless it is used by most sellers of diamonds in the world.

Scale presents itself in the form of two sheets with prices. The first sheet is placed on the cost of the round stones, and the second, respectively, on the cut "Pear" and other varieties of fancy handle material.

## How to use the scale Rapoport

For the calculation of the value of the diamonds shall be based on the highest estimated cost of a similar stone that is ready to put the sellers or dealers for their customers. This means that each time the value of a diamond is subjective is reviewed. The price shown is on the rocks, according to a scale ranging from 0.01 carat and goes up to 10.99 carat, if the cut grade of the stone meets the condition of "very good" (Very Good).

Stones with excellent cut (Excellent) will cost 10 or 20% more.

The value of a gemstone is determined by its carat (according to the expert) multiplied by the price per carat for a stone of this class. So, for a 1 carat you can get up to hundreds of dollars.

Price list for Rapport scale consists of 18 tables in which all values are set by weight. Moving between these values, it is possible to observe an increase in value on diamonds, starting with 20% and ending at 40%. For example, if you take a diamond stone weight in carat G class\VS1, which is worth about 8 thousand dollars, the stone weight of 1.5 carats will cost 11 thousand dollars. When this income is added to the so-called prize, when there is transition from one weight to another position, the award is 35%.

If you want to calculate the "net" cost of the diamond, should be based on a table from the directory Rapoport, where the calculation is in USD per 1 point. Meanwhile, to find out how much the diamond you need the numbers from the corresponding row of the classifier is multiplied by 100 points, so one carat equaling 100 points.

As you can see, the very scale Rapoport is a kind of directory for dealers. But not always according to this scale it is possible to sell the benefits of uncut diamonds.

# Advice 2: How to use a torque wrench

When servicing certain components and aggregates of the vehicle is required to ensure the tightening of the thread with a certain force which is called torque. To ensure the correct choice efforts, using special torque wrench. The handling of this tool should be accuracy and precision.

## How does a torque wrench

Torque wrench in appearance resembles a regular ratchet, equipped with special scale intended for determining the desired force transmitted to the threaded connection. Depending on the type of the instrument scale may look like a dial gauge, but can also be supplied with a digital indicator screen.

In its most common form, the instrument has a scale embossed on the key; an indicator of the achieved effort in this case will be a "click". This torque wrench has a handle, rotatable, and two scales, where it is applied the number of divisions. The main scale is located on the fixed part of the tool, and support – on a rotating arm.

Usually the torque wrench has a strictly limited range of permissible effort that is specified in the technical documentation or in the instructions to the device. The width of the range can be defined by the limit marks on the main scale of the instrument.
Choosing a key for a car service in advance to find out what efforts might be needed when tightening the threaded connections on separate units.

## How to use a torque wrench

Let's say that you want to tighten the threaded connection with a certain force. First you need to select a key with appropriate range. On the base of the tool is screwed the movable arm. She will move to a fixed scale tool. When the arm nearly reaches the desired mark on the main scale, you should switch the attention to scale and rotate the auxiliary handle to the level, exactly corresponding to the desired force. The key is ready to use.

Now to a torque wrench is necessary to attach the end die of the desired size, i.e. corresponding to a nut. Upon subsequent tightening the nut at some point will achieve the effort that will be clear by the distinctive click, which will publish the tool. An experienced master can also feel the onset of moment, change efforts are perceived by the hand.
Click means that the desired tightening force has been achieved, so that the process can be stopped.

If you continue to tighten the threaded connection further, not paying attention to a click torque tool will work like an ordinary key, tightening the nut on and making clicking noises. The key worked for a long time, and the connection has not been spoiled by excessive force, such situations should be avoided. After fully screwing the nuts to the desired position the knob should return to its original position, twisting it back.

# Advice 3: How to use a caliper

Not only in manufacturing but also in everyday life there is often a need to know the size of a small detail. To measure the diameter of the drill or wire size to determine the size of the inner recess in the workpiece, it's best to use a caliper. This tool is very easy to use, although it requires a bit of skill.

## The device of the caliper

Measuring ruler is extremely simple in use, but to measure its items can only be with a very low degree of accuracy. If the conditions of the problem impose higher requirements to the measurement results, it is best to use a special kind of measuring tool, which is called caliper.
This device gives the possibility to determine the internal and external dimensions of objects and also the depth of small holes.

Traditional Vernier caliper consists of an elongated rod, is provided with stationary jaws. The rod moves the frame having movable elements and the retaining screw. On a flat surface of the rod are cut-off, reproducing a scale with divisions of one millimeter. The length of the standard scale, as a rule, equal to 150 mm, although you can find more impressive models. On the movable part of the tool, you can see the auxiliary scale called a Vernier.

## How to use a caliper

To measurements with conventional calipers, you need to prepare the tool. This is to differentiate between the jaws of the caliper at a sufficient distance, and then tightly compress them measured object, for example, a drill bit or metal rod. Do not need to exert undue force so as not to damage the instrument.

Now we need to look at the first (left) label, available near the bottom of the scale to figure out which division it was established. For example, if the mark lies between zero and one, this means that the object has a size less than a centimeter. The next step is to figure out which of the divisions of the upper scale mark coincides. If it is opposite of division 7, the size of the object being measured is 7 mm.

With the help of Vernier caliper can be measured also, and a few tenths of a millimeter. If the bottom label was established between numbers 7 and 8, you need to see which of the labels exactly matches the line on the upper scale, making it a single line. Coincided the fifth label? This suggests that to the result you want to add a millimeter.
The number of additional labels on the lower scale can be set to 10 or 20, depending upon the accuracy class of the caliper.

Inner diameter caliper to measure is also not too difficult. For this purpose, the tool has two slightly pointed sponge at the top. They must be inserted between the inner surfaces of cavities or tubes, and then push until it stops. All other measurement steps will be the same as those described above for external measurements.
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