Buitenmicrometers

Buitenmicrometers, also known as outside micrometers, are precision measuring instruments used to determine external dimensions of objects with high accuracy. They are widely employed in mechanical engineering, metalworking, and quality control to measure external diameters, thicknesses, and stepped features.

Construction and components: A typical buitenmicrometer has a rigid C-shaped frame that braces the stationary anvil and the movable spindle. It uses a micrometer screw with a 0.5 mm pitch per revolution, a graduated sleeve with a main scale in millimeters, and a thimble with a vernier or fine scale that provides readings in 0.01 mm increments (in metric versions) or 0.001 inch increments (in inch versions). A ratchet stop provides constant measuring force, and a locking screw secures the spindle position during reading.

Operation and reading: The object is placed between anvil and spindle; the spindle is advanced until contact with the object with light, consistent pressure using the ratchet. The reading is obtained by adding the main scale reading on the sleeve to the thimble reading on the rotating dial; the zero line on the thimble is aligned to indicate precise value. Some models include a reference zero that can be adjusted using a spanner.

Range and accuracy: Common metric buitenmicrometers measure from 0 to 25 mm, 25 to 50 mm, or 50 to 150 mm depending on model, with typical resolutions of 0.01 mm (10 μm); higher-precision variants offer 0.001 mm. Accuracy depends on instrument quality and calibration and is often stated as ±0.01 to ±0.03 mm for standard tools.

Calibration and care: Zero check before use; calibrate with gauge blocks; clean and lubricate; store in protective case.