Mechanical engineering calculators
The calculations you look up again on every job, right here. No account needed.
These are the calculations Simptech uses in its own contract design work, published as they are. Change an input and the drawing and the numbers follow immediately. Everything runs in your browser; what you type is never sent to a server.
Beam deflection and bending stress
Point load and distributed load, anywhere along the span. Six cross-sections, four support conditions, with a bending moment diagram.
Bolted joint
Torque coefficient from the friction coefficients. Load sharing, bearing pressure under the head, and margins against slip and shear.
Compression coil spring
Spring rate and load, torsional stress with the Wahl correction. Spring index and solid length checked as well.
Slider-crank mechanism
Displacement and velocity, plus crank torque, connecting rod force and side thrust for a given piston force.
Toggle mechanism
The force multiplier behind a production clamp. Force ratio and clamping force, with the buckling of the links.
These are simplified calculations intended for first-pass sizing. Always carry out your own verification before building and manufacturing real hardware.
Why we publish them
If you are outsourcing design, it is hard to judge the other side's engineering ability in advance. We cannot show what our projects contained, because of the confidentiality we owe our clients. So instead we show you the calculations we actually do when we design.
Use them freely. If, having used them, you would like us to take on what comes next, just get in touch.
The same calculation, on your terms
What is published here is general, for first-pass sizing. On a real site the materials are already chosen, the safety factors have been settled in-house, and every department has its own words for things. Build those in and the tool becomes your standard in-house tool.
We take that on as custom tool development. It need not be a design calculation: model selection, reconciling parts lists, and the hand-work that comes round every week are all in scope. As well as browser tools, we build Windows and macOS desktop applications and Office add-ins.
Talk to us about design, prototyping or decarbonization
We can join a project already under way, and we take on short engagements.
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