Knowledge of saw chain use

The saw chain is an essential part of the chain saw. If there is no saw chain, the chain saw cannot work or can be called a saw. It is just an engine, and some users do not know much about the saw chain. Therefore, the following is a brief introduction.

The composition of the saw chain

The saw chain consists of a combination of left incisors, right incisors, intermediate guide teeth (also called drive teeth) and rivets.

Second, the chain saw chain model

At present, our common ones are German STIHL and American OREGON CARLTON. Take the Carlton saw chain as an example: A1L A- means the pitch is 3/8, converted to decimal number 0.375, 1 --- means the central tooth thickness is 0.050, L-- means the shape of the cutting teeth is right angle. Common methods of Carlton ordinary saw chain are as follows:

Note: 3/8LP is a small 3/8, converted to decimal number .365. (Unmarked character symbols)

The pitch and center tooth thickness of OREGON, STIHL are expressed in Arabic numerals. The Latin letters behind the numbers indicate the shape and characteristics of the teeth, not listed here.

On the same type of saw chain, the pitch, that is, the center distance between the two holes of the front teeth, the middle guide and the connecting piece, the pitch (pitch) is the same, all in inches and inches. The scales we use are all metric and must be converted during measurement. 1 inch = 25.4 mm, if you want to calculate the metric size, please multiply it by 25.4 and the size it represents. Example B3L, pitch: 25.4×0.404 = 10.26 mm; middle guide tooth thickness: 25.4×0.063 = 1.6 mm

3. Chain saw chain, chain length

Take the 18-inch B3 saw chain as an example, the saw chain is riveted into a ring with 30 cutting teeth on the left and right. Each of the two cutting teeth has 4 pitches (the pitch on the cutting teeth is also calculated), 0.404×4×30 = 48.48 (inches) 1 ft = 12 inches, the result data is divided by 12 inches, that is 48.48 ÷ 12 = 4.04 feet. This chain is 4.04 feet long. (Multiplied by 2 in the middle guide tooth)

Each box saw chain is 100 feet long, and the pitch of each type of saw chain is different, so the number of cutting teeth is also different. The connecting teeth connected to each cutting tooth have 4 pitches. The calculation formula and data are as follows:

Type: 100 (inches) ÷ (0.375×4÷12) = 800

Type B: 100 (inches) ÷ (0.404×4÷12) = 742.57 --- 744

Type K: 100 (inches) ÷ (0.325×4÷12) = 923.076 --- 924

Type N: 100 (inches) ÷ (0.365×4÷12) = 821.917 ---- 822

In order to prevent cutting deviations, ordinary saw chains should be paired left and right, that is, symmetrical, the number of teeth is uniform, the 100 feet produced by the manufacturer is not only an integer, but also some given chain saw cutters are uniform. However, some guide plates are not standard, the rivet chain saw cutter must be an odd number, there are two left (or right) cutters on one side, plus the connecting piece and the middle guide tooth, then the total length is calculated by the middle guide tooth . Each of the two middle teeth has two pitches (the pitch of the middle teeth is also calculated), and then its length is multiplied by the pitch multiplied by 2, then the number of teeth, and then divided by 12. Chain, the number of teeth in the middle is 59:

0.325 x 2 x 59÷12 = 3.196 ft. The calculation method of other saw chain models is the same, but the pitch is different.

In addition, the two data to remember are: 1 foot = 12 inches 1 inch = 25.4 mm