Wedge design 101
A starter guide for wedge geometry, friction angle, and force distribution in simple machines.
This guide is prepared for quick engineering review. Critical design decisions still require the relevant standard, supplier data, and engineering approval.
Problem / Objective
A wedge can transform a small input force into a high normal force. If friction, crushing stress, and surface quality are ignored, locking or wear can appear.
Assumptions
- The wedge is treated as rigid.
- Friction coefficient is estimated for the surface pair.
- Contact pressure stays within a safe material limit.
Step by step method
- Define wedge angle and contact length.
- Write the relation between input force and normal force.
- Check the friction angle.
- Review surface pressure and local crushing.
- Plan release direction and lubrication.
Common mistakes
- Assuming zero friction.
- Using a contact area larger than the real surface.
- Discovering self-locking only after assembly.
Related calculators
Related glossary terms
Quick FAQ
Question: What happens when wedge angle decreases?
Normal force rises for the same input force, but friction and locking risk also increase.
Question: Which material works for a wedge?
Use a machinable material with known wear behavior and enough contact pressure capacity.
Question: Is lubrication needed?
Lubrication reduces wear when contact pressure or motion frequency is high.
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