DIN 94 Split Cotter Pin / Straight

Steel split cotter pin DIN 94 to the German standard is a locking fastener, a common type of hardware. The DIN 94 split cotter pin corresponds to the Russian GOST 397, as well as the international standard ISO 1234 and the European standard EN 21234. Split cotter pins are made of spring low-carbon steel (less than 0.20%) without coating — plain black — but more often with an electroplated zinc coating: white and yellow zinc, or with chrome plating or nickel plating, from austenitic stainless steel grade A2 AISI304 and acid-resistant steel A4 AISI 316, as well as from a copper alloy — brass.

General description

Alongside the split cotter pin there are needle spring cotter pins, commonly called a “pin” — DIN 94, DIN 11024, DIN 11023, M 8383. A pin is a rod that is inserted into a hole in a part and prevents one-sided unscrewing or loosening of another part. The shape of the DIN 94, DIN 11023 cotter pin prevents it from falling out of the hole. For example, to keep wheels from shifting off their axle, DIN 94 cotter pins are used in the automotive industry. Split cotter pins (pins) DIN 94 are also used in weapons manufacturing as a safety device in hand grenades. All split and spring cotter pins, whether DIN 94 or DIN 11024, 11023, are used only in unstressed connections of elements and parts. In window manufacturing — for installing window bolts — split window cotter pins DIN 94 are used. Spring split cotter pins DIN 94 are used to secure slotted castle nuts DIN 935 and low castle nuts DIN 937, as well as bolts to DIN 962 with a hexagon head and a through-hole for the cotter pin in the bolt head (form SK) or on the bolt shank (form S). In the most critical parts and structures, cotter-pinning of bolts and nuts is used — the most effective method of locking.

The DIN 94 cotter pin is a rod bent in half, made of carbon steel without coating or with a zinc coating, or from a copper alloy — brass, or from stainless steel, where a loop (eye) is formed at the bend. Split and spring cotter pins are usually used only once and must be replaced with a new part if reused. Of the two ends of the DIN 94 cotter pin, one is made slightly longer than the other — for convenient bending apart in different directions during installation. The loop of the DIN 94 spring cotter pin acts as a depth stop when inserted into the hole. The eye serves for convenient removal of the cotter pin from the connection when installing another one. A split cotter pin can be installed by hand or with a special tool, such as pliers or flat-nose pliers.

Types of cotter pins

DIN 94 is a spring split cotter pin, a low-carbon rod bent in two. It prevents self-loosening of nuts and parts. DIN 11024 (form D with a ring, form E without a ring) is a needle spring cotter pin made from a carbon steel wire rod, where one half is smooth and straight while the other has a bend depending on the cotter pin’s form. The needle spring cotter pin helps secure detachable elements in mechanisms and equipment.

DIN 11023 is a quick-release ring cotter pin (pin). It is used for assembling and disassembling detachable connections. An analogue is the ring cotter pin M 8383 without a pin. The most widely used type of cotter pin is the one with flat ends. There are also cotter pins with serrated or curled ends, providing additional locking reliability after installation. FLOK supplies these modifications of cotter pins as well.

Installing DIN 94 split cotter pins

To install a DIN 94 cotter pin in a slotted castle nut DIN 935 and DIN 937, as well as in special bolts for cotter pins DIN 962, the ends of the cotter pin must be inserted into the through-slots, after which the ends are bent apart in opposite directions from each other. In this case, to increase the cotter-pinning range (tightening travel) in nuts, special slots are cut — their number equal to the number of nut faces (for example, in the hexagon nut DIN 935 — 6 slots). The depth of the slots in the DIN 935 nut is greater than the diameter of the DIN 94 cotter pin. The most effective way to install a DIN 94 spring cotter pin is to position the cotter pin’s ring perpendicular to the axis of the DIN 935, DIN 937 nut or the DIN 962 bolt. A more installation-friendly method is to position the ring parallel to the axis of the bolt and nut: one end against a face of the nut, the other against the end of the bolt.

Application of the DIN 94 cotter pin

The main application of spring and split cotter pins DIN 94, DIN 11024 (form D, form E) is in instrument making, machine tool building, the automotive industry, construction and mechanical engineering, for securing parts under strong and prolonged vibration, and for locking nuts and bolts in threaded connections.

Manufacture and production of DIN 94 split cotter pins

DIN 94 split cotter pins are made of low-carbon steel. Steel DIN 94 cotter pins are produced with various coatings: white and yellow zinc plating (yellow passivated), nickel plating (nickel), chrome plating. Oxidized DIN 94 cotter pins without coating — plain steel, black — are also used.

DIN 94 spring cotter pins are also made of austenitic stainless steel A2 — it withstands heat and mechanical treatment well, is not subject to corrosion, and cotter pins made of this steel are non-toxic, do not conduct electricity and are non-magnetic. DIN 94 A2 cotter pins are made in accordance with the Russian steel standard 12Kh18N9T.

Spring split and needle cotter pins DIN 94, DIN 11024 are made of heat-resistant, acid-resistant stainless steel A4 — domestic steel standard 10Kh17N13M2T. These cotter pins are non-magnetic and do not conduct electricity. DIN 94, DIN 11024 A4 is used in acidic and alkaline environments, for example when fastening parts, as well as when installing instruments and equipment in chlorinated and marine environments, when installed in swimming pools. It is also used in alkaline and acidic environments, when installing equipment in food production, the textile and chemical industries.

DIN 94 cotter pins are also made of brass — a copper-zinc alloy. Brass DIN 94 cotter pins are produced both without additional coating and with nickel or chrome plating. Brass DIN 94 cotter pins have anti-corrosion properties, which is why they are often used in agriculture, industry and the marine sector. If non-magnetic properties are required, or the fastener must not conduct electricity, brass DIN 94 cotter pins are suitable for these purposes.

Split cotter pins DIN 94, DIN 11024, DIN 11023 can be used for nuts and bolts with metric and inch threads (American and British type).

These cotter pins are used for bolts and nuts: American type — coarse pitch UNC, fine pitch UNF; British type — coarse pitch BSW, fine pitch BSF. The most common nut and bolt diameters for DIN 94, DIN 11024 cotter pins are No.1 / No.2 / No.3 / No.4 / No.5 / No.6 / No.8 / No.10 – 3/16” / No.12 / ¼” / 5/16” / 3/8” / 7/16” / ½” / 9/16” / 5/8” / ¾” / 7/8” / 1” / 1 1/8” / 1 ¼” / 1 ½” / 1 ¾” / 2” / 2 ¼” / 2 ½” / 2 ¾” / 3”.

Size table

d1 (max)	1.4	1.8	2.3	2.9	3.2	3.7	4.2	4.6
d1 (min)	1.3	1.7	2.1	2.7	3.0	3.5	4.0	4.4
a (max)	2.5	2.5	2.5	3.2	3.5	4.0	4.0	4.0
b	3.2	4.0	5.0	6.4	7.0	8.0	8.5	10.0
c (min)	2.4	3.2	4.0	5.1	6.1	6.5	7.6	8.0
c (max)	2.8	3.6	4.6	5.8	6.8	7.4	8.2	9.2

l (mm)	d
	1.6	2	2.5	3.2	3.5	4.0	4.5	5.0
10
12
14
16
20
25
28
32
40
50
60
63
71
80
90
100

d1 (max)	5.9	7.5	9.5
d1 (min)	5.7	7.3	9.3
a (max)	4.0	4.0	6.3
b	12.6	16.0	20.0
c (min)	10.3	13.1	16.6
c (max)	11.8	15.0	19.0

l (mm)	d
	6.3	8.0	10.0
12
14
16
20
25
28
32
40
50
60
63
71
80
90
100