Angles and flatness

Precision squareSquare (engineer's square)

Also called: engineer's square, I-type square, square with base

≡Standards, measuring range and accuracy

Standard

JIS B 7526:1995 Squares^[1][2]

Measuring range

byMaker
- Obishi Keiki I-type Nominal 50–500 mm

^[2]1 source, for reference

Resolution / graduation

—Not confirmed in public sources

Accuracy (instrument error / maximum permissible error)

byMaker
- Obishi Keiki I-type, nominal 100 Squareness grade 1 ±3.0 µm, grade 2 ±7.0 µm

^[2]1 source, for reference

▦Types

I-shaped (thick, can stand upright), etc.

^[2]1 source, for reference

✋Usage steps

Used to check the squareness of jigs and tools, to measure the squareness of products, and as a master for measuring instruments^[2]
No primary source was found on how to apply it (viewing by light gap, etc.)Not confirmed in public sources

Printed from Kezuriba (kezuriba.net/en/gauges/square/)

✓Care, storage, inspection and calibration

Care and storage

Rust-proof after use (a caution common to Obishi Keiki manuals)^[2]

Inspection and calibration

⇄Related instruments

Surface plate Height gauge

📚Sources

Content without a mark is what agreed across two or more sources from different publishers. Procedures and cautions are summarized in Kezuriba's own words based on the sources, and the diagrams were drawn by Kezuriba. Accuracy values are manufacturers' published figures, not values from JIS tables.