C-1: Thread Code:

All labels have the denominator as 8, and then directly call the number of the numerator.

Ex: 1/8 x 0.50 -PPB: 1 minute screw x 0.50" long, PPB

Ex: 5/16 x 0.50 –PPB = 2.5/8 x 0.50-PPB: Half-thread screw x 0.50" long, PPB

Ex: 5/32 x 0.50 -PPB =1.25/8 x 0.50-PPB: 1 minute, 2 centimeters and a half screws x 0.50" long, PPB

Ex: 1/4 x 0.50-PPB= 2/8 x 0.50-PPB: 2 points screw x 0.50" long, PPB

Note: Coarse teeth or fine teeth are sometimes indicated.

UNF: Fine teeth: more commonly used in the electronics industry.

UNC: Coarse teeth: Heavy mechanical structure is more commonly used.

Ex: 3/8 x 0.50, UNF –PPB: 3-point fine thread screw x 0.50" long, PPB.

C-2: Length Code:

It is marked in inches and must be multiplied by 25.40 to convert to mm.

Measure with a buckle gauge, the metric thread is consistent with the metric thread, and the inch thread is consistent with the inch thread.

You can also use a caliper to measure the outer diameter and pitch of the thread.

The outer diameter of the metric thread is in millimeters, such as 6, 8, 10, 12, 18, 20 mm, etc. The pitch is also in millimeters, such as 0.5, 0.75, 1, 1.5, 2, 3, etc.

The outer diameter of the inch thread is in inches, (each inch is equal to 25.4 mm) such as 3/16, 5/8, 1/4, 1/2, etc. Therefore, the reading of the outer diameter with a metric caliper often has irregular decimals. .

The imperial pitch is expressed by the number of teeth per inch. Set the caliper at 25.4 mm, align one ruler tip with the thread tip, and the other ruler tip if the thread tip is aligned with the inch thread, if the thread tip is not aligned, it should be a metric thread.

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

The thread specifications specified in inches are inch threads, such as G1". The thread specifications specified in millimeters are metric threads. For example: M30.

The imperial system is determined by how many teeth there are in one inch (2.54 cm), generally 55 degrees. The metric system is the pitch of the pitch determined by the distance between the tips of the two teeth, generally 60 degrees.

Anchor screws: screws used to fasten the machine on the ground. Also called anchor bolts.

The difference between British and American screws is difficult to distinguish by visual inspection. The difference between British and American screws is that the screwing angle of British screws is 55 degrees, while the screwing angle of American screws is 60 degrees. These two standard screws are in most cases. It can be used universally at the time, but 1/2 specification screw is not available, because the standard thread of inch 1/2 is 1/2-12 thread, while the American thread is 1/2-13 thread.