Bolt Torque Spec Calc
iOS Universel / Utilitaires
Built for mechanics, millwrights, and equipment installers who need bolt torque on the bench - not a desktop tool.
WHAT IT DOES
Looks up torque values for standard bolt sizes and grades using the T = K x D x F formula with K = 0.20. SAE grades 2, 5, and 8 across 28 sizes from #6-32 to 1-1/2 inch. Metric classes 4.6, 8.8, 10.9, and 12.9 across 17 sizes from M3 to M36. Dry vs. lubricated multiplier applied to the result.
INPUTS
- Standard: SAE or Metric
- Bolt size (28 SAE or 17 metric sizes available)
- Bolt grade or class
- Lube condition: Dry or Lubricated
RETURNS
- Torque in ft-lb
- Torque in N·m
CALCULATION BASIS
- Torque formula: T = 0.20 x D x F
- Preload F = 75% of proof strength times tensile stress area
- Lubricated multiplier: 0.75 times the dry value
WHY THIS APP, NOT THE FREE ONES
- Math is shown - formula and assumed K factor visible, not hidden.
- 45 size and grade combinations covered in one tap.
- Works offline - shop floor, field repair, no Wi-Fi. Always available.
- No login. No ads. No telemetry. No subscription.
PRICING
$1.99. Pay once, own it. Lifetime access on iPhone, iPad, and Mac via Family Sharing.
NOT A SUBSTITUTE FOR
Manufacturer-specified torque values for safety-critical fasteners. Calibrated wrench certificates. Specific K-factor adjustments for anti-seize, plating, or galvanized threads - this app uses K = 0.20 for both dry and lubricated, with the 0.75x multiplier as the only lube adjustment. Verify against the OEM tightening spec for the specific application.
Quoi de neuf dans la dernière version ?
Listing refresh - clarified the description, inputs/outputs, and which standards are referenced. No functional changes.
