KOIZUMI Planimeter Model Compensating Optical Tracer – No. 27716 – Manual Area Measuring Instrument for Maps & Blueprints – Vintage Drafting & Engineering Tool

This is a superb example of a precision mechanical calculating instrument: a KOIZUMI Compensating Optical Planimeter, identified by serial number 27716. Used primarily by draftsmen, cartographers, surveyors, and engineers throughout the 20th century, this tool was the definitive method for accurately measuring the area of irregular shapes on maps, blueprints, and technical drawings.

Crafted with the meticulous attention to detail characteristic of Japanese instrumentation, this planimeter represents a time when complex calculations were solved with elegant mechanical solutions.

Key Features & Specifications:

• Manufacturer & Model: KOIZUMI “Compensating Optical Planimeter.” Koizumi was a renowned Japanese manufacturer of precision measuring tools.

• Serial Number: 27716 – This unique identifier is ideal for collectors and for verifying the instrument’s provenance.

• Type: Compensating Polar Planimeter with an Optical Tracer. The optical tracer (the small magnifying lens with a etched dot or circle) allows for extremely precise tracking of a shape’s outline.

• Function: Accurately measures the area of any irregular 2D shape by simply tracing its perimeter. The result is read from the measuring drum and vernier scales.

• Units: Can be calibrated to measure in various units (square inches, square centimeters, etc.) based on the scale of the drawing.

• Condition: [You must specify here, for example:] This is a vintage item in good, used condition, showing signs of age and use consistent with its history. All components are present. The optical glass is clear. We recommend it for collection, display, or for use by an enthusiast familiar with calibrating vintage instruments.

What’s in the Box?

• The KOIZUMI Planimeter main unit.

• The tracing arm with optical tracer.

• (If applicable) The original fitted wooden case or storage box.

A Piece of Technical History
This isn’t just a tool; it’s a conversation piece and a testament to the ingenuity of pre-digital engineering. It is perfect for:

• Collectors of vintage scientific, engineering, and surveying instruments.

• Museum displays focusing on technology, cartography, or engineering.

• Designers & Engineers who appreciate the history of their craft.

• Unique Décor for a study, office, or workshop with a steampunk or technical aesthetic.