Pantograph scaling calculator

Ideal geometric scale mapping on one axis.

linkages-pantograph.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

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

Scenario	scale	outputTravelmm
	2	100
	2	80

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.

travel budget100.00 mm✓ passes

BASELINE INPUTS

inputTravel50 mminputArm100 mmoutputArm200 mm

CALCULATED

scale2

outputTravel100 mm

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Pantograph scaling
# Scope: Ideal geometric scale mapping on one axis.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

inputTravel = 50 mm
inputArm = 100 mm
outputArm = 200 mm

scale := outputArm/inputArm
outputTravel := inputTravel*scale [mm]

check travel budget: outputTravel <= 120 mm

scenario alternative: inputTravel = 40 mm

Calculated from your source · not saved

Baseline · Baseline

travel budget100.00 mm ✓ passes

alternative · alternative

travel budget80.00 mm ✓ passes

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.

scale: scale = outputArm/inputArm
output travel: outputTravel = inputTravel*scale [mm]

Original worked example

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

Given

input travel: 50 mm
input arm: 100 mm
output arm: 200 mm

Calculated

scale: 2
output travel: 100 mm

Assumptions and limits

Ideal geometric scale mapping on one axis.

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: Pantograph scaling. Inputs: link geometry; input path. Outputs: output path; motion scale; workspace. Model scope: Planar rigid-link geometry with explicit joints and branches. 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: link geometry, input path
Outputs: output path, motion scale, workspace
Modes: calculate, compare, sweep
Drawing: Interactive linkage

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