# Bolt Torque Spec Calc — SAE Grade · Metric · Lubed

> SAE Grade · Metric · Lubed (iPhone/iPad app by Shanghai Sheyuan Network Technology Co., Ltd..)

- Source: https://appshunter.io/ios/app/bolt-torque-spec-calc/id6760930975 (this page in markdown: same URL + `.md`)
- Developer: [Shanghai Sheyuan Network Technology Co., Ltd.](https://appshunter.io/developer/1560626858)
- Category: Utilities
- Price: $4.99
- Age rating: 4+
- Requires: iOS 17.0 · 1 MB
- Languages: English
- Released: 2026-03-23
- Data updated: 2026-08-10
- User reviews in markdown: https://appshunter.io/ios/app/bolt-torque-spec-calc/id6760930975/reviews.md

## What is Bolt Torque Spec Calc?

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.


## Version history (last 5 releases)

### 1.0.5 — 2026-06-27

Added a More Pro Tools section to discover related field calculators.

### 1.0.4 — 2026-06-11

Performance and stability improvements.

### 1.0.2 — 2026-05-18

Listing refresh - clarified the description, inputs/outputs, and which standards are referenced. No functional changes.

### 1.0.1 — 2026-04-29

Listing refresh - clarified the description, inputs/outputs, and which standards are referenced. No functional changes.

### 1.0 — 2026-03-23

No release notes.

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All apps by Shanghai Sheyuan Network Technology Co., Ltd.: https://appshunter.io/developer/1560626858

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-10.*