DIN 404 Screw with Increased Cylinder Head with Ball, with Two Holes

The German standard DIN 404 covers a security screw with an increased cylinder head. The head is fitted with two radial holes and a slot for driving with a flat-tip screwdriver. The holes are intended for fastening a sealing wire: this type of screw is used to seal products against unauthorized access. Screws of this type are used in instrument making and other industrial sectors.

Design features and materials

The screws have an increased-size cylinder head and full metric thread on the shank. Materials:

• Steel with property class 5.8 — for low loads.
• Stainless steel grades A2 and A4 — enhanced corrosion resistance, use in aggressive environments.
• Steel with a protective zinc coating.

Thread diameter ranges from M3 to M6, shank length from 4 to 30 mm. The fastener is driven with a screwdriver into a prepared threaded hole; a sealing wire, which cannot be removed without damaging the seal, is inserted through the holes in the head.

Dimensions of DIN 404 cylinder head screws in mm:

b	19	22	25	28
dk	5.5	7	8.5	10
dh	1.5	2	2.5	3
k	4	5	6.5	8
l	d
	M3	M4	M5	M6
4
5
6
8
10
12
16
20
25
30