Clamp force and friction holding calculator

Lever-actuated friction clamp at one contact.

statics-clamp-force.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	normalN	holdingN
	150	45
	120	36

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

holding target45.00 N✓ passes

BASELINE INPUTS

effort30 Nhandle100 mmjawArm20 mmfriction0.3

CALCULATED

normal150 N

holding45 N

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Clamp force and friction holding
# Scope: Lever-actuated friction clamp at one contact.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

effort = 30 N
handle = 100 mm
jawArm = 20 mm
friction = 0.3

normal := effort*handle/jawArm [N]
holding := friction*normal [N]

check holding target: holding >= 40 N

scenario alternative: effort = 24 N

Calculated from your source · not saved

Baseline · Baseline

holding target45.00 N ✓ passes

alternative · alternative

holding target36.00 N × fails

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

normal: normal = effort*handle/jawArm [N]
holding: holding = friction*normal [N]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

effort: 30 N
handle: 100 mm
jaw arm: 20 mm
friction: 0.3

Calculated

normal: 150 N
holding: 45 N

Assumptions and limits

Lever-actuated friction clamp at one contact.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Clamp force and friction holding. Inputs: disturbance load; friction; clamp geometry. Outputs: required preload; slip margin. Model scope: Rigid-body, quasistatic equilibrium. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: disturbance load, friction, clamp geometry
Outputs: required preload, slip margin
Modes: calculate, compare, sweep
Drawing: Free-body diagram

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS