How to quickly distinguish between an inch screw and a metric screw

The angle in the imperial system is 55° and the angle in the metric system is 60°

Summary. Pro, their tooth profile angle is not the same, the metric thread tooth angle is 60 degrees, and the inch thread tooth angle is 55 degrees, but it is not easy to distinguish it with the naked eye, so it is necessary to use the pitch gauge to measure, and the pitch gauge is also divided.

Metric and Imperial can be used to quickly identify metric and imperial threads based on thread depth. Because the inch thread is much deeper when the pitch is about the same.

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How do you distinguish between imperial and metric screws? How are they different?

Pro, their tooth profile angle is not the same, the metric thread tooth angle is 60 degrees, and the inch thread tooth angle is 55 degrees, but it is not easy to distinguish it with the naked eye, so it is necessary to use the pitch gauge to measure, the pitch gauge is also divided into metric and imperial according to the thread depth to quickly identify whether the reputation of the hole system and the imperial thread. Because when the lifting pitch is about the same, the inch thread is much deeper. If my answer is helpful to you, please give a thumbs up (in the lower left corner), I look forward to your like, your efforts are very important to me, and your support is also the motivation for my progress.

If you feel that my answer is still satisfied, you can quietly click on my avatar for one-on-one consultation. Finally, I wish you good health and a good mood!

If my answer is helpful to you, please give a thumbs up (comment in the lower left corner), look forward to your like, your efforts are very important to me, and your support is also the driving force for my progress. If you feel that I am satisfied with the answer of Fu Lu, you can click on my avatar for one-on-one consultation. Finally, I wish you good health and a good mood!

With the buckle gauge, it is a metric thread that coincides with the metric tooth shape, and an inch thread that coincides with the imperial thread.

It is also possible to measure the outer diameter of the thread and the pitch with a caliper.

The metric thread outer diameter is measured in millimeters, such as 6, 8, 10, 12, 18, 20 mm, etc., and the pitch is also measured in millimeters, such as, 1, 2, 3, etc.

The outside diameter of an inch thread is measured in inches, (each inch is equal to millimeters), such as 3, 16, 5, 8, 1 4, 1 2, etc., so metric calipers are used to measure the outside diameter, often with irregular decimal places. Imperial pitch is expressed in terms of the number of teeth per inch. Set the caliper in millimeters, align one ruler tip with the thread tip, and the other ruler tip should be an inch thread if the thread tip is aligned, and if the thread tip is not aligned, it should be a metric thread.

When measuring the pitch, it is best to print the tip of the thread upside down on the white chalk, which is relatively clear and easy to measure. To measure the metric pitch, you should measure a length, such as 10, 15, 20, mm, etc., and count how many teeth are contained to calculate the pitch.

Generally, among the screws sold in China, most manufacturers are in accordance with the national mandatory national standard, that is, GB to standardize production, or there are also according to the national recommended standard, that is, GB T to implement. Anyway, you can do both, depending on the customer's needs and the consideration of the scope of application of the product by its own manufacturers. So, for some of the merchants to be produced, is the national standard also applicable, no, it will involve the imperial standard, that is, BS.

How to distinguish between metric and imperial systems:

1. You can use calipers to measure the outer diameter of the screw to see if its size is consistent with the metric system or the imperial system.

2. The thread can be measured with a thread gauge, and the tooth profile angle of the ordinary metric thread is 60 degrees, while the inch thread is generally 55 degrees (but the imperial thread also has a 60 degree thread).

3. Measuring pitch, the size of the metric system is generally an integer (or divisible by 5).

4. You can also take a metric nut and try to screw it, and if you can screw it in, it must be a metric screw. Most people must be very clear that the diameter of metric screws in the national standard is generally an integer, such as M3, M4, M6, etc., while the representation of imperial screws is different, such as 3 16, 3 8, 5 12, 1 8, etc., 1 inch is equal to 8 cm, and 1 inch is equal to the metric system, and you can know how big the screw is needed through conversion.

Nominal thread outer diameter (thread specification): metric and imperial.

Metric threads are commonly used in 2;;; 3;;;4;;;

5;6;8;10;12;14;16;20。Unit: mm (mm).

Nominal length: There are two types: metric and imperial.

Metric nominal length Common values are ,

Unit: mm (mm).

Imperial nominal length Common values are . Unit: in (inches).

Head type: The type of head shape is indicated by letters, please refer to the common screw head type classification above.

Indication of imperial thread grade (e.g., 1 4-28UNF-1B) 2007-07-2914:241 4 is the large diameter (outer diameter) of the thread, calculated in inches, 1inch=

28 refers to 28 threads per inch, which specifies how big the pitch is.

UNF is UnitedfineThread, that is, the inch fine tooth thread, some are UNC, and C refers to Coarse, that is, coarse teeth.

1b is the tolerance accuracy class, and similar grades include 2a, 3a, and so on.

Uniform thread marking for the imperial system.

Coarse teeth: UNC

Fine teeth: unf

Extra-fine teeth: unff

Fixed pitch: un

Its standard method:

1) Coarse tooth series: 3 8-16UNC-2A (where 3 8 inches is the thread diameter, 16 is 16 teeth per inch (teeth, since.)

The pitch has been calculated), UNC is the series code, and 2A is the accuracy level.

2) Fine tooth series: 3 8-24UNC-2A (fine tooth is 24, larger than coarse tooth 16, smaller than extra fine 32,)

3) Extra-fine tooth series: 3 8-32UNFF-2A

4) Fixed pitch series: 3 8-20UN-2A (fixed pitch 20 teeth,

Metric teeth, as we all know, are the standard teeth stipulated in our China. The British system, the American system, the German standard, the Japanese standard, etc., are the teeth stipulated by other countries. So how can you tell the difference!

The easiest way to do this is to take a metric tooth nut and see how the screw can be twisted up. If you can twist it, it's the screws of the metric teeth. If you can't twist it, it's not.

The metric teeth of ordinary machine screws are generally 60 degrees. The American (British) is 55 degrees. If we can't see with our inner eye, what kind of tooth it is.

Then we can find a metric, American, imperial, and so on. Use these dental gauges to find out what kind of tooth it is. If yes:

The screws that can't be snapped in with metric dental gauges are American (English) screws, and the screws that can be snapped in are metric (note: the snap-in is tight-fitting, if both seem to be snap-in for individual specifications, you can look at the light spot to see that the seam is that kind of screw.) It's a very simple and convenient way.

Dental gauges are bought in stores that sell measuring tools, and they are not expensive) Many company buyers and new sales screws do not know how to distinguish between imperial screws, American screws, and metric screws. For this situation, Manager Zhu of Shenzhen Chuanggu screw manufacturer would like to briefly introduce how to distinguish them. Here are some simple and practical methods.

There are three different national standard screws, the inch screws belong to the British national standard screws, and the American screws belong to the American standard screws. Metric screws belong to our Chinese national standard screws. It's the difference of simple names.

Judging from their three kinds of screw threads, imperial screws are called imperial teeth, American screws are called American teeth, and metric screws are called metric teeth.

The simplest and most practical way to distinguish the three types of screws is to find a metric nut and screw it into the screw with a metric nut, of course, the corresponding nut size is required. If you can screw it in, and it is screwed relatively smoothly, it is a metric screw. If you can't screw it, it's American screws and imperial screws.

Metric teeth, as we all know, are the standard teeth stipulated in our China. The British system, the American system, the German standard, the Japanese standard, etc., are the teeth stipulated by other countries. So how can you tell the difference!

The easiest way to do this is to take a metric tooth nut and see how the screw can be twisted up. If you can twist it, it's the screws of the metric teeth. If you can't twist it, it's not.

The metric teeth of ordinary machine screws are generally 60 degrees. The American (British) is 55 degrees. If we can't see with our inner eye, what kind of tooth it is.

Then we can find a metric, American, imperial, and so on. Use these dental gauges to find out what kind of tooth it is. If yes:

The screws that can't be snapped in with metric dental gauges are American (English) screws, and the screws that can be snapped in are metric (note: the snap-in is tight-fitting, if both seem to be snap-in for individual specifications, you can look at the light spot to see that the seam is that kind of screw.) It's a very simple and convenient way.

Dental gauges are available in stores that sell measuring tools and are not expensive).

Summary. The difference between 6mm and 1 4 joints is different, and the screw diameter is different. 1. The standards are different

1 4 screws are the imperial standard, the meaning of the logo is: imperial 2 inch screws, 6mm screws are the metric standard, and the meaning of the logo is: metric 6mm screws.

2. The screw diameter is different: the outer diameter of the inch 1 4 screw is: 2 p, and the conversion metric system (1 p, the outer diameter of the metric 6mm screw is:

Metric 6mm, the outer diameter of its screws is 6mm.

This is an inch screw.

The difference between 6mm and 1 4 joints is different, and the screw diameter is different. 1. The standard is different: 1 4 screws are imperial standards, and the meaning of the logo is:

Inch 2-in-1 screws, 6mm screws are metric standards, and the meaning of the logo is: metric 6mm screws. 2. The diameter of the screws is different

The outer diameter of the inch 1 4 screw is: 2 p, convert to metric (or stuffy 1 p, the outer diameter of the metric rubber 6mm screw is: metric 6mm, and the outer diameter of the screw is 6mm.

The diameter of this screw is about 6mm, and the screw acre distance is about 6mm, and it is a commonly used screw for connecting mechanical parts, with good strength and corrosion resistance. It can be used in a variety of such machinery and equipment, such as automobiles, motorcycles, tractors, excavators, etc., as well as household appliances, electronic products, etc.

The main difference between an imperial screw and an American screw is that the unit of pitch is different, with an inch screw in inches and an American screw in millimeters. In addition, the pitch of the inch screw is generally larger than that of the American screw, so the strength of the inch screw is also greater than that of the American screw.