DIN 7981 and GOST 10621-80 are standards for self-tapping screws with a semicircular head.
Self-tapping screws according to DIN 7981 and according to GOST 10621-80 mainly differ in the shape of the end of the threaded rod, the shape of the slots for the screwdriver and the range of sizes.
Self-tapping screws according to DIN 7981 are available with pointed or blunt shank ends. The sharp shape of the end of the screw allows you to use it without pre-drilling a hole in the base material. Cross-shaped slots for a screwdriver have the shape of Phillips (H) or Pozidriv (Z). The PZ slot allows a higher screw tightening torque than the PH.
Self-tapping screws according to GOST 10621-80 are produced only with a blunt end and with a straight slot or Phillips cross slot (H). The largest maximum thread diameter and longer length of self-tapping screws according to GOST 10621-80, which allows them to be used as a replacement for a conventional fastener where its use is impossible.
| Параметр | DIN 7981 | ГОСТ 10621-80 |
| d - номінальний діаметр різьблення, мм | 2.2, 2.9, 3.5, 3.9, 4.2, 4.8, 5.5, 6.3 | 2.5, 3, 4, 5, 6, 8 |
| l - довжина саморіза, мм | від 4.5 до 38 | від 6 до 50 |
| Форма кінця стрижня | загострена та тупа | тупа |
| Тип шліцю під викрутку | хрестоподібний PH або PZ | прямий та хрестоподібний PH |