Steel – 8.8; 10.9; 12.9 (galvanic zinc, zinc lamellar coating);
Stainless steel – A2-70; A2-80; A4-70; A4-80;
Inch thread
| d | M3 | M4 | M5 | M6 | M8 | M10 | M12 | М14 | М16 | М20 | М22 | М24 | |
| P | 0,5 | 0,7 | 0,8 | 1 | 1,25 | 1,5 | 1,75 | 2 | 2 | 2,5 | 3 | 3,5 | |
| k | 1,86 | 2,48 | 3,1 | 3,72 | 4,96 | 6,2 | 7,44 | 8,4 | 8,8 | 10,16 | 13,1 | 14 | |
| dk | 6,72 | 8,96 | 10,2 | 13,44 | 17,92 | 22,4 | 26,8 | 30,88 | 33,6 | 40,32 | 36 | 39 | |
| s | 2 | 2,5 | 3 | 4 | 5 | 6 | 8 | 10 | 10 | 12 | 14 | 14 | |
| ISR | - | Т20 | Т25 | Т30 | Т40 | - | - | - | - | - | - | - | |
| b | 18 | 20 | 22 | 24 | 28 | 32 | 36 | 40 | 44 | 52 | 56 | 60 | |
| l | мін. | 5 | 6 | 6 | 8 | 10 | 12 | 20 | 30 | 20 | 35 | 60 | 40 |
| макс. | 30 | 50 | 80 | 120 | 160 | 160 | 200 | 80 | 200 | 200 | 100 | 240 | |
Features of the countersunk screw with an internal hexagon
Countersunk screw with an internal hexagon DIN 7991 is a high-strength fastener. It is used in work with metal sheet elements and materials from solid types of plastics. Specific performance and operating recommendations depend on the selected type, accuracy class (high or normal), and raw material (stainless steel, brass, alloys, carbon steel with or without a protective coating).
The main areas of application of metal products din 7991:
food industry (production and household appliances);
chemical industry (mechanisms with increased danger);
medicine (apparatus with uneven load distribution);
shipbuilding and automobile construction;
domestic use.
This hardware provides an attractive aesthetic appearance of the joint: correctly selected dimensions of the screw, combined with its seat, allow you to place the end at the same level as the upper part or a few millimeters deeper (recessed screw). Installation requires a minimum of additional equipment: a hand wrench with a hexagon or a power tool with a suitable bit.
Eurobolt Ukraine company – low price for high quality
A screw with a countersunk head and an internal hexagon meets all the requirements of safety and aesthetics. The products manufactured at our facilities can withstand the highest static and dynamic loads, so they receive positive feedback from users.
You can buy these and other fastening elements at the central office, as well as through our representative offices. Independent removal and address delivery by transport companies is possible.
Analogues of DIN 7991:
ISO 10642 – Countersunk head and hexagon or TORX socket head screws. ISO 14582 – Countersunk head screws with TORX key hole. DIN 963 – screws with countersunk head and straight slot. DIN 965 – screws with a countersunk head and cross-shaped slot or with a hole for a TORX key.
Marking
d – nominal thread diameter
P – threading step
k – screw head height, max.
dk – screw head diameter, max.
s – the size of the internal hexagon is key
ISR – TORX socket wrench size
b – screw thread length, max.
l – screw length