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Clevis Pin Size Chart (ASME B18.8.1)

Guide · Updated October 28, 2026

A clevis pin is a headed pin with a cross hole near the other end. It goes through a clevis and a rod eye and is held in with a cotter pin, so the joint can swing and can be taken apart with pliers. Inch clevis pins are covered by ASME B18.8.1, the same standard as inch cotter pins. The chart below gives sizes 3/16 to 1 in. The figures match between the ASME B18.8.1 Table 1 clevis pin dimensions and the Almabolt clevis pin catalog table, which lists the same B18.8.1 values.

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Step by step

  1. Measure the shank: Mike the pin shank or the clevis bore. Clevis pins run a few thousandths under nominal, so a 1/2 in pin mikes .491 to .496 in.
  2. Check the grip: Measure the clevis jaw width plus the rod eye. The standard length in the chart fits a standard clevis without spacers.
  3. Find the hole location: For other lengths, the cotter hole center sits at length minus J from the underside of the head. J is .09 to .18 in depending on size.
  4. Pick the cotter pin: Use the cotter size listed for the pin. The hole is sized for that cotter with a little clearance.
  5. Choose material: Plain low or medium carbon steel is standard. Ask for case hardened pins where they wear, or stainless for wet or outdoor use.
  6. Install: Slide the pin in head up where you can, fit a washer if the drawing calls for one, then fit and spread the cotter pin.

ASME B18.8.1 clevis pin dimensions (inches)

Columns are: nominal size, shank diameter A, head diameter B, head height C, cotter hole diameter E, point diameter F, standard length G for a standard clevis without spacers, head to hole center H for that length, basic end to hole center J, and the cotter pin size to use. Head chamfer D is .02 in on 3/16, .03 in on 1/4 to 3/8, .04 in on 7/16 and 1/2, .06 in on 5/8, .07 in on 3/4, .09 in on 7/8 and .10 in on 1, all ±.01.

How to read the chart

The shank is always under nominal, so a clevis pin is a slip fit in a hole drilled or reamed to the nominal size. The head is a little over one and a half times the shank on small pins and closer to one and a quarter on large ones, so it bears on the clevis without sticking out much. The point is turned down below the shank so the pin starts easily. Standard lengths are set for a standard clevis. If you need another length, the standard asks that it be kept to .06 in steps where you can, and the hole center goes at length minus J.

Other tolerances worth knowing: the cross hole must be within .010 in of the pin axis on 3/16 and 1/4 pins and within .020 in on larger sizes, and square to the axis within 2°. The underside of the head must be square to the shank within 2°. Holes are chamfered or deburred at both ends so the cotter goes in without catching.

Worked example: pin for a 1/2 in clevis with a long grip

A 1/2 in clevis has a .75 in jaw gap and .25 in thick jaws on each side, so the total grip is 1.25 in. You also want a .06 in washer under the cotter, so the hole edge must clear 1.31 in from under the head. The hole is .136 to .151 in, so its center needs to be at least 1.31 + .076 = 1.386 in from the head. With J = .15 in, the pin length is 1.386 + .15 = 1.536 in. Round up to the next .06 in step and order a 1/2 × 1.56 in pin. Check: hole center at 1.56 − .15 = 1.41 in, which clears the washer. Use a 1/8 in cotter pin.

Worked example: what size is this pin?

A worn pin mikes .370 in on the shank with a .50 in head and a .11 in cross hole. A .370 shank falls inside .368 to .373, the 3/8 range, and the .50 head and .104 to .119 hole agree. It is a 3/8 clevis pin and takes a 3/32 cotter. Measure the shank away from the worn bearing area, since wear can make it look like a smaller size.

Worked example: drilling a cross hole in a cut pin

You cut a 5/8 in pin down from 2.00 in to 1.75 in and need a new cotter hole. J for 5/8 is .15 in, so the hole center goes at 1.75 − .15 = 1.60 in from under the head. Drill it with a 9/64 drill (.1406), which sits in the .136 to .151 hole range, in a V-block so it stays on center. Deburr both ends and fit a 1/8 cotter.

Clevis pins vs other pins

Clevis pins are for joints that pivot or come apart often, such as linkages, cylinder ends and trailer hitches. Hitch pins and quick release pins are faster to remove but cost more. Shoulder bolts give a tighter fit and are held with a nut. Dowel pins and taper pins locate parts that do not move. Where a clevis pin will see heavy wear, use a hardened pin and a bushed clevis.

Common problems

FAQ

What size is a 1/2 inch clevis pin really?

The shank is .491 to .496 in, so it slips into a 1/2 in reamed or drilled hole. The head is .61 to .63 in across and .14 to .16 in tall.

What cotter pin goes with a clevis pin?

3/16 and 1/4 pins take a 1/16 cotter, 5/16 to 7/16 take 3/32, 1/2 and 5/8 take 1/8, and 3/4 to 1 take 5/32.

How do I find the hole location on a non-standard length?

Hole center from under the head = pin length minus J. J is .09 in for 3/16 and 1/4, .12 in for 5/16 to 7/16, .15 in for 1/2 and 5/8, and .18 in for 3/4 to 1.

Are clevis pins hardened?

Not as standard. B18.8.1 calls for low or medium carbon steel. Case hardened pins are .010 to .016 in deep and must resist a No. 58 file.

Pin and retaining-ring size charts

Picking a fastener to locate or retain a part? Compare the other pin and ring charts in this set:

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General shop information only — follow your drawing, tool maker's data and your quality system.