Bolt Double-Shear Load Capacity Calculator

Estimate the shear failure load of a bolt in double shear — the standard clevis configuration where a bolt passes through a rod end bore between two bracket ears.

FASTENER SHEAR STRENGTH · ASME B18.2.1 DIMENSIONS

Bolt Double-Shear Load Capacity

Estimates the shear failure load of a bolt in double shear — the standard clevis configuration where a bolt passes through a rod end bore between two bracket ears.

Bolt Diameter (D)
[Inches]

Assumes the unthreaded shank spans both shear planes — good clevis design practice keeps threads out of the shear plane.

Bolt Grade / Material
τ ≈ 0.6 × UTS

Operating Shear Load (P)
[lbf]

Dynamic Shock Multiplier (Kd)
SYZ Guideline

Estimated Double-Shear Capacity

35,343 lbf

Single-shear capacity (one plane): 17,671 lbf

✔
Sf = 2.01 : 1 — adequate margin by SYZ guideline (Sf ≥ 2.0).

Engineering Model (approximation, not a certified shear rating)

Standard Reference
Bolt nominal diameters follow ASME B18.2.1. Shear strength ≈ 0.6 × ultimate tensile strength is a widely used engineering approximation, not a codified single value — for certified shear strength, consult ASTM F606 fastener test data or the manufacturer’s published shear rating.

Calculation Method
A = π/4·D² · Double Shear = 2 × A × τ · Sf = Capacity / (P × Kd)

Assumptions & Limitations

Assumes the bolt shank (not threads) spans both shear planes — verify your grip length keeps threads out of the joint.
τ≈0.6×UTS is a common approximation, not a guaranteed value — actual shear strength varies by manufacturing process and material lot.
Does not check bearing/tear-out failure of the bracket or rod end material around the bolt hole — a separate failure mode that can govern before the bolt itself shears.
Does not model fatigue, preload, or clamping friction contribution to joint capacity.

STATIC REFERENCE DATA

Reference: Double-Shear Capacity by Bolt Size & Grade

Precomputed values from the exact formula used above — useful as a quick lookup without re-entering inputs.

Bolt Size	Grade 5 (~120ksi)	Grade 8 (~150ksi)	Metric 12.9 (~177ksi)	High-Strength ~170ksi class
3/8″	15,904 lbf	19,880 lbf	23,415 lbf	22,531 lbf
7/16″	21,648 lbf	27,059 lbf	31,870 lbf	30,667 lbf
1/2″ (calculator default)	28,274 lbf	35,343 lbf	41,626 lbf	40,055 lbf
5/8″	44,179 lbf	55,223 lbf	65,041 lbf	62,586 lbf
3/4″	63,617 lbf	79,522 lbf	93,659 lbf	90,124 lbf
1″	113,097 lbf	141,372 lbf	166,504 lbf	160,221 lbf

WORKED EXAMPLE

1/2″ Grade 8 Clevis Bolt Under Rallycross Loading

A rod end mounts to a bracket with a 1/2″ Grade 8 bolt in double shear. The estimated operating shear load is 8,000 lbf under performance-circuit conditions.

Bolt: 1/2″ diameter, Grade 8 (τ ≈ 90 ksi shear strength).
Shear area per plane A = π/4×0.5² ≈ 0.196 in². Single-shear capacity ≈ 17,671 lbf. Double-shear capacity ≈ 35,343 lbf.
Operating load P = 8,000 lbf, Kd = 2.2 (performance circuit / rallycross curb impacts).
Sf = 35,343 / (8,000 × 2.2) ≈ 2.01 : 1 — clears the SYZ guideline minimum (Sf ≥ 2.0), but only just.
Given the thin margin, also check bracket/rod-end bearing (tear-out) capacity around the bolt hole — this calculator only checks the bolt itself, not the surrounding material.

Related reading: Control Arm Resource Hub →