Do you know how to use these tools in a mechanical way?

Steel ruler

Steel straightedge is the simplest length measuring tool, its length has 150,300,500 and 1000mm four specifications. Below is a commonly used 150mm steel ruler.

Steel ruler is used to measure the length and dimension of parts, but its measurement results are not very accurate. This is because the spacing of the steel ruler is 1mm, and the width of the line itself is 0.1 ~ 0.2mm, so the reading error is relatively large when measuring, can only read the number of millimeters, that is, its minimum reading value is 1mm, smaller than 1mm, can only be estimated.

If the steel ruler is used directly to measure the diameter of the part (axle diameter or aperture), the measurement accuracy is worse. The reason is: in addition to the reading error of the steel ruler itself is relatively large, but also because the steel ruler can not be placed in the correct position of the diameter of the part. Therefore, the diameter and size of parts can also be measured by steel ruler and internal and external calipers.

two

Inside and outside calipers

Below are two common types of inside and outside calipers. Inside and outside calipers are the simplest comparative measuring tools. The outer caliper is used to measure the outside diameter and plane, and the inner caliper is used to measure the inside diameter and groove. They themselves can not directly read the measurement results, but the measured length size (diameter is also a length size), read on the steel ruler, or in the steel ruler first remove the required size, and then to check whether the diameter of the part is in line with.

1. Adjust the caliper opening. First check the shape of the jaws. The shape of the jaws has a great influence on the accuracy of measurement.

Comparison of good and bad mouth shape.

When adjusting the caliper opening, gently tap the two sides of the caliper foot. Use both hands to adjust the caliper to an opening close to the size of the workpiece, then tap the outside of the caliper to reduce the opening, and tap the inside of the caliper to increase the opening. See Figure 1 below. However, do not knock the jaws directly, as shown in Figure 2 below. This will cause measurement error due to the caliper mouth damage surface. Not to knock the caliper on the guide rail of the machine tool. See Figure 3 below.

2, the use of external caliper caliper in steel ruler to take off the size, as shown in the following figure, a clamp foot measurement surface on the end face of the steel ruler, another clamp foot measurement face quasi required size engraved line in the middle, and the two measurement surface line should be parallel to the steel ruler, the line of sight should be perpendicular to the steel ruler.

With the steel ruler to take the size of the outer caliper to measure the diameter, to make the two measuring surface of the vertical axis of the parts, by the weight of the outer caliper sliding parts outer circle, our hands should feel that the outer caliper and parts outer circle is just point contact, the distance between the two measuring surface of the outer caliper, is the diameter of the measured parts. Therefore, measuring the outer diameter with the caliper is to compare the tightness of the outer caliper contact with the outer circle of the parts. As shown in the figure below, the weight of the caliper can just slide down. If when the caliper slips through the outer circle, we have no contact feeling, it means that the outer caliper is larger than the outer diameter of the parts, such as by the weight of the outer caliper can not slide through the outer circle of the parts, it means that the outer caliper is smaller than the outer diameter of the parts. Do not put the caliper skew on the workpiece measurement, so there is an error. As shown in the picture below. Because the caliper is elastic, it is wrong to press the outer caliper hard over the outer circle, not to put the caliper across the card, as shown in the following figure. For large size outer calipers, the measured pressure of sliding across the outer circle of the part by its own weight is too large. At this time, the calipers should be held for measurement, as shown in the figure below.

3, the use of the inner caliper when measuring the inner diameter with the inner caliper, the connection line of the measuring surface of the two feet should be vertically intersected with the axis of the inner hole, that is, the two measuring surface of the foot should be the two ends of the diameter of the inner hole. Therefore, when measuring, the measuring surface of the foot of the clamp should be stopped on the hole wall as a fulcrum.

Above the foot of the clamp slightly inside some gradually outward test, and swing along the circumference of the hole wall, when the distance along the circumference of the hole wall can swing is the minimum, it means that the two measuring surface of the caliper foot has been in the two ends of the diameter of the inner hole. Then move the caliper slowly from outside to inside to check the roundness tolerance of the hole.

Measure the inside diameter with an inner caliper already measured on a steel ruler or on an outer caliper.

is to compare the tightness of the inner caliper in the part hole. If the caliper in the hole within the larger free swing, that caliper size is smaller than the aperture; If the caliper can not be put into the hole, or into the hole after tight can not swing freely, it means that the size of the caliper is larger than the aperture, such as the caliper into the hole, according to the above measurement method can have 1 ~ 2mm free swing distance, then the aperture and the size of the caliper is equal. Do not hold the caliper with your hand when measuring.

So that the feel is not, it is difficult to compare the degree of tightness of the inner caliper in the parts hole, and make the caliper deformation and measurement error.

Caliper is a simple measuring tool, because it has the characteristics of simple structure, convenient manufacturing, low price, easy to maintain and use, widely used in the measurement and inspection of parts size requirements are not high, especially for the forging blank size measurement and inspection, caliper is the most appropriate measuring tool. Although calipers are simple measuring tools, as long as

We master well, also can obtain higher measurement accuracy. For example, compare two

with an outer caliper

When the diameter of the root shaft is large, the difference of the shaft diameter is only 0.01mm, experienced master

can also tell. For example, when the inner caliper and outside diameter percent ruler are used to measure the inner hole size, experienced teachers are fully sure to use this method to measure the high precision of the inner hole. This method of inner diameter measurement is called. Inner card gauge. , is to use the inner caliper to read the exact size on the outside diameter percent ruler.

Then measure the inner diameter of the parts; Or the inner card in the hole to adjust the tightness of the contact with the hole, and then read the specific size on the outside diameter percent ruler. This measuring method is not only a good way to measure the inner diameter in the absence of a precise inner diameter measuring tool, but also, for the inner diameter of a part, as shown in Figure 1-9, because of the shaft in the hole, it is difficult to use a precise inner diameter measuring tool, so the method of measuring the inner diameter with an inner caliper and outside diameter percentage ruler can be used to solve the problem.