Screw Jack Force & Torque Calculator
Torque to raise a load on a power screw, with the self-locking check.
Self-locking and efficiency are enemies: a jack that holds by friction wastes >50% of your cranking in that same friction. Ball screws flip the trade — 90% efficient, zero hold.
Formula
Screw Jack Force & Torque Calculator is a free screw jack torque for mechanical and machine-design engineers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Screw Jack Force & Torque Calculator
Torque to raise a load on a power screw, with the self-locking check. The calculation implements T = F·(d_m/2)·tan(λ+φ); self-locking when λ < φ (Power screws — Shigley ch. 8). Self-locking and efficiency are enemies: a jack that holds by friction wastes >50% of your cranking in that same friction. Ball screws flip the trade — 90% efficient, zero hold.
How to use Screw Jack Force & Torque Calculator
- 1Enter Load in kg.
- 2Enter Mean screw diameter in mm.
- 3Enter Lead (advance per rev) in mm.
- 4Enter Thread friction µ (Lubricated steel/bronze 0.10–0.15).
- 5Read Torque to raise, Screw efficiency instantly — no submit button needed.
- 6Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Screw Jack Force & Torque Calculator?
- ✓Implements the standard formula — T = F·(d_m/2)·tan(λ+φ); self-locking when λ < φ
- ✓Reference cited on-page: Power screws — Shigley ch. 8
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Built-in engineering verdict flags out-of-range results instantly
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Screw Jack Force & Torque Calculator use?+
It computes T = F·(d_m/2)·tan(λ+φ); self-locking when λ < φ, per Power screws — Shigley ch. 8. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
Self-locking and efficiency are enemies: a jack that holds by friction wastes >50% of your cranking in that same friction. Ball screws flip the trade — 90% efficient, zero hold.
Is this suitable for machine design coursework?+
Yes — these are the exact Shigley/Machinery's-Handbook formulas, with the substitution shown step by step, so you can follow the worked example into your own calculation sheet.
Is the Screw Jack Force & Torque Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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