One of the most common is British bolt, American bolts Specification of British bolts: Common specifications are 2 #; 4 #; 6 #; 8 #; 10 #; 12 #; 1 / 4; 7 / 32; 5 / 16; 3 / 8; 1 / 2; 9 / 16; 3 / 4.Unit in (in.). British nominal length specifications: common values are 1 / 4,5 / 16,3 / 8,7 / 16,1 / 2 5 / 8,3 / 4,1,23.Unit: in (in.). The American standard is made of British system, and the national standard is made of public (meter) system. American standard general thread description: 0 # -80,2 # -56,4 # -40,6 # -32,8 # -32,10 # -24,1 / 4-20,5 / 16-18, etc., this description in front refers to the thread address diameter, behind is refers to how many teeth in 1 inch. The metric thread description: M3-0.5, M4-0.7, M5-0.8, M6-1.0, M8-1.25, etc., this description before also refers to the thread address diameter, then refers to the tooth distance. Except for the thread, other sizes are also different: if it is a hexagonal nut, the thickness is not the same size as the opposite side: if it is a screw, the head size is also different.1. Our company offers the full range from pre-sales to after-sales service, from product development to audit the use of maintenance, based on strong technical strength, superior product performance, reasonable prices and perfect service, we will continue to develop, to provide the high-quality products and services, and promote lasting cooperation with our customers, common development and create a better future. 2. Since the establishment of our company, we have realized the importance of providing good quality products and the best before-sales and after-sales services. Most problems between global suppliers and clients are due to poor communication. Culturally, suppliers can be reluctant to question things they do not understand. We break down those barriers to ensure you get what you want to the level you expect, when you want it.