The hole
The nominal size is the diameter of the split pin hole in the bolt or clevis pin. The pin is a little thinner: a size 4 measures 3.5 to 3.7 mm across both legs, so it goes in a 4 mm hole with play.
Reference tool — not a selection
Find the split pin for a hole, a bolt or a clevis pin before the size goes in an RFQ.
ISO 1234, DIN 94
Split pin, hole or bolt.
Pick what you have and enter a designation, the hole, the bolt or the clevis pin. A hole measured in the bolt goes in the field below: the finder reads it as the largest split pin that goes in it, and with a bolt size it checks that the hole and the table agree. Below, an offered split pin can be checked against the result.
Examples:
Replacement check
On the designation alone: the finish and the condition are checked separately.
All 130 engineering tools
Split pins lock castle nuts on engine and pump bolts, and clevis pins on deck gear, linkages and valve handles all over a ship, and a split pin is named by the hole it goes in. Enter a designation (ISO 1234 4 x 32, DIN 94 3.2x20, split pin 5x40), a hole diameter (hole 4), a bolt (M24, castle nut M24) or a clevis pin (clevis pin 20): the finder gives the nominal size, the pin and eye dimensions, the bolt and clevis pin diameters the standard lists for that size and its standard lengths, draws the pin to scale, checks an offered split pin and writes an RFQ line.
Inch split pins, sizes below 0.6 and above 20 mm and other standards are not in this finder. The material and the finish do not follow from the size: give them in the request.
How a split pin is sized
Hole, eye, legs.
The eye
The eye is bent from the same wire: c is its width, b its length. The eye stays outside the hole, so c is larger than the hole.
The legs
The length l runs from under the eye to the end of the shorter leg. The longer leg stands out by a, which gives a grip to open the legs and bend them over.
| Nominal size | Pin d | Eye c | Eye b, about | Leg offset a | Bolts | Clevis pins | Lengths l |
|---|---|---|---|---|---|---|---|
| 0.6 | 0.4–0.5 | 0.9–1 | 2 | 0.8–1.6 | — | — | 4–12 |
| 0.8 | 0.6–0.7 | 1.2–1.4 | 2.4 | 0.8–1.6 | — | — | 5–16 |
| 1 | 0.8–0.9 | 1.6–1.8 | 3 | 0.8–1.6 | 3.5–4.5 | 3–4 | 6–20 |
| 1.2 | 0.9–1 | 1.7–2 | 3 | 1.25–2.5 | 4.5–5.5 | 4–5 | 8–25 |
| 1.6 | 1.3–1.4 | 2.4–2.8 | 3.2 | 1.25–2.5 | 5.5–7 | 5–6 | 8–32 |
| 2 | 1.7–1.8 | 3.2–3.6 | 4 | 1.25–2.5 | 7–9 | 6–8 | 10–40 |
| 2.5 | 2.1–2.3 | 4–4.6 | 5 | 1.25–2.5 | 9–11 | 8–9 | 12–50 |
| 3.2 | 2.7–2.9 | 5.1–5.8 | 6.4 | 1.6–3.2 | 11–14 | 9–12 | 14–63 |
| 4 | 3.5–3.7 | 6.5–7.4 | 8 | 2–4 | 14–20 | 12–17 | 18–80 |
| 5 | 4.4–4.6 | 8–9.2 | 10 | 2–4 | 20–27 | 17–23 | 22–100 |
| 6.3 | 5.7–5.9 | 10.3–11.8 | 12.6 | 2–4 | 27–39 | 23–29 | 32–125 |
| 8 | 7.3–7.5 | 13.1–15 | 16 | 2–4 | 39–56 | 29–44 | 40–160 |
| 10 | 9.3–9.5 | 16.6–19 | 20 | up to 6.3 | 56–80 | 44–69 | 45–200 |
| 13 | 12.1–12.4 | 21.7–24.8 | 26 | up to 6.3 | 80–120 | 69–110 | 71–250 |
| 16 | 15.1–15.4 | 27–30.8 | 32 | up to 6.3 | 120–170 | 110–160 | 112–280 |
| 20 | 19–19.3 | from 33.8 | 40 | up to 6.3 | — | — | 160–280 |
The nominal size is the diameter of the split pin hole. Pin d: the smallest and largest size across both legs. Bolts and clevis pins: the diameters the standard lists for each size, over the first value up to and including the second. Lengths l: the shortest and longest standard length; between them the series 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 22, 25, 28, 32, 36, 40, 45, 50, 56, 63, 71, 80, 90, 100, 112, 125, 140, 160, 180, 200, 224, 250, 280 mm. A value is given only where two independent tables agree; values two tables do not agree on are left out: the smallest leg offset a of sizes 10 to 20 and the largest eye width c of size 20 (the tables differ in the last figure), and the bolt and clevis pin diameters of sizes 0.6, 0.8 and 20, which only one table gives.
Sources
Every value appears in at least two independent published tables of ISO 1234, one of them the text of the standard itself, and is left out where tables differ. The bolt and clevis pin diameters of sizes 1 to 16 are in the standard and in a distributor table.
Before you send the request
Questions about split pins in an RFQ
What is the size of a split pin?
The size is the diameter of the hole the pin is for, not the pin itself. A split pin of size 4 goes in a 4 mm hole; its two legs together measure 3.5 to 3.7 mm, so it slides in. ISO 1234 has sixteen sizes: 0.6, 0.8, 1, 1.2, 1.6, 2, 2.5, 3.2, 4, 5, 6.3, 8, 10, 13, 16 and 20 mm. Measure the hole; an old pin measured across its legs gives a figure a little under its size.
Which split pin goes with an M24 bolt and a castle nut?
ISO 1234 lists the bolt diameters each size is for: bolts over 20 up to 27 mm take a size 5, so an M24 bolt takes a 5 mm split pin, provided the hole in the bolt is 5 mm. The hole decides: if the old bolt has a 4 mm hole, a size 5 pin does not go in. For clevis pins the standard has its own column, and for railway use or clevis pins with side forces that change direction it recommends the next larger size.
Is a DIN 94 split pin the same as ISO 1234?
DIN 94 is withdrawn: ISO 1234, published in Germany as DIN EN ISO 1234, replaced it, and split pins are still sold under both numbers. The designation is the same, size by length, e.g. 4 x 32. Published tables differ in the last figure of two values for the largest sizes, so those values are left out here. In the request, give the standard as it is written in the parts list.
How long should the split pin be?
Long enough to pass through the bolt and the castle nut with both legs free to bend over. ISO 1234 gives each size its own range from one series of lengths, 4, 5, 6, 8, 10, 12 and so on up to 280 mm: size 4 from 18 to 80 mm, size 6.3 from 32 to 125 mm. The length l is measured from under the eye to the end of the shorter leg. Measure the old pin that way and ask for the same length.
What should the request include?
The standard with the size and the length (ISO 1234 4 x 32), the material (steel, stainless steel A2 or A4, brass or copper), the finish and the quantity. If the old pin is lost, give the hole diameter in the bolt and the bolt size, with a photograph.
Size found?
Send the line with a photograph of the old pin.
A row of the standard is a cross-check of sizes, not a part selection. Attach the photograph and your measurements, and Vessel Core checks them before an offer goes back.
Buyer tools
