Recent Blogs
Spring Cyclograph Mechanism Explained: Parts, Decaying Spiral Formula, Diagram and Worked Example
How a Spring Cyclograph draws decaying spirals and damped curves for draughtsmen, engineers, and ornament designers — geometry, formula, and a worked example.
Spherometer Mechanism Explained: How It Works, Parts, Diagram, Formula and Uses
A spherometer measures the radius of curvature of lenses, mirrors, and curved surfaces. Used by opticians and machinists for sub-micron accuracy.
Self-registering Barometer Mechanism Explained: How a Barograph Records Atmospheric Pressure
How a self-registering barometer works, with formulas, a worked meteorological example, and tradeoffs vs aneroid and digital pressure loggers.
Section Liner Mechanism: How the Pawl-and-Rack Indexing Works, Parts, Uses, and Hatching Formula
Section Liner explained — how draughtsmen use this drawing tool to hatch parallel section lines fast and consistently in mechanical and architectural drafting work.
Roller Parallel Ruler Mechanism Explained: How It Works, Parts, Diagram and Marine Navigation Uses
How a Roller Parallel Ruler works, the geometry behind its tracking accuracy, and why marine navigators still use it on paper charts today.
Reflecting Drawing Board Mechanism: How It Works, Optical Diagram, Parts and Uses Explained
How a Reflecting Drawing Board works — the half-silvered mirror trick draughtsmen used to trace 3D objects flat onto paper, with worked examples and tolerances.
Omni-telemeter Odontograph Mechanism Explained: Parts, Formula, and Gear-Tooth Layout Uses
The Omni-telemeter Odontograph is a draughting instrument for laying out gear teeth profiles. See how it works, formulas, and applications in horology and machine design.
Great Curve Delineator Mechanism: How It Works, Diagram, Parts, Formula and Uses
The Great Curve Delineator draws large-radius arcs without a centre point. Used by shipwrights, naval architects and pattern lofts. Geometry, formula, examples.
Trammel for Drawing Ellipses: How the Archimedes Mechanism Works, Parts and Uses
How a Trammel of Archimedes draws true ellipses for pattern-makers, sign carvers and toolmakers. Geometry, formula, worked example and tolerance rules.
Tracing Bar Mechanism: How It Works, Parts, Formula, and Drafting Uses Explained
Tracing Bar explained — how draughtsmen and instrument makers use a sliding bar with a stylus to copy, scale, and transfer curves with sub-millimetre accuracy.
Parabola Scriber Mechanism: How the Focus-Directrix Linkage Draws a True Parabola
A Parabola Scriber draws true parabolic curves directly on stock for solar dish layout, antenna reflectors, and optical tooling. Geometry, formulas, examples.
Lazy-tongs Pantograph Mechanism: How It Works, Parts, Scale Formula & Engraving Uses Explained
How a lazy-tongs pantograph copies and scales drawings using crossed extensible links. Used in drafting, sign-making, and engraving since the 1600s.
Geared Ellipsograph Mechanism: How It Works, Cardan-Circle Geometry, Parts, and Uses Explained
Geared ellipsograph explained — how the 2:1 epicyclic gearing traces true ellipses for draughting, optics tooling, and architectural layout. Formula, examples, specs.
Ellipsograph Turntable Mechanism: How It Works, Parts, Formula and Diagram Explained
How an Ellipsograph Turntable draws true ellipses for draughtsmen, jewellers and pattern-makers — geometry, formula, worked example, and selection trade-offs.
Eidograph Mechanism Explained: Parallel-Bar Drawing Copier, How It Works, Parts, Formula, Diagram
Eidograph explained — how the pivoted-bar copying mechanism scales drawings, where it beats the pantograph, and how draughtsmen still use it today.
Cyclograph Mechanism Explained: How a Trammel Ellipsograph Traces Ellipses, Parts and Uses
A cyclograph traces ellipses and curves on technical drawings. See how draughtsmen use it for shaft sections, cam profiles, and isometric circles.
Conchoid Delineator Mechanism: How It Works, Parts, Diagram, and Uses in Drafting
How a conchoid delineator draws Nicomedes' conchoid curve mechanically — geometry, formula, and worked example for draughting and optical layout work.
Three Part Parallel Ruler Mechanism: How It Works, Parts, Geometry & Uses Explained with Diagram
How the Three Part Parallel Ruler transfers angles across a drawing board without slip. Components, formula, worked example for drafting and navigation work.