The thread of the filter is now simply broken down by severa
The thread of the filter is now simply broken down by severa In the national standard standard thread marking method, the first letter represents the thread code, for example, M means common thread, G means non thread sealing pipe thread, R means thread seal pipe thread, Tr represents trapezoidal thread and so on. The second numbers represent the nominal diameter of the thread, that is, the large diameter of the thread. It represents the maximum diameter of the thread, and the unit is millimeter. The later symbols are the pitch, the rotation, the tolerance code of the middle diameter, the name of the top diameter tolerance and the code of the rotation length. M20 * 1.5 means a common thread with a nominal diameter of 20mm and a pitch of 1.5mm. Inch unified thread is widely used in inch country. It can be divided into three series: coarse tooth series UNC, fine tooth series UNF, extra fine tooth series UNFF, plus a fixed pitch series UN. Annotation methods: thread diameter - Per Inch series code - precision sample: coarse series 3/8 - 16 UNC - 2A fine series 3/8 - 24 UNF - 2A extra fine series 3/8 - 32 UNFF - 2A constant pitch series 3/8 - 20 UN - 2A 3/8 said the first digit of the screw diameter for unit inch conversion to metric units mm is multiplied by 25.4, which is 3/8 * 25.4=9.525mm; second, third, 24, 32, 16 and 20 per inch (the number of teeth in the length of 25.4mm); third after the words UNF, UNFF, UNC, code for UN series code, the last two 2A precision class.
