In machining and quality control processes, high-accuracy measuring instruments are needed to verify that parts are machined within tolerance limits. Offering far greater precision than standard callipers, micrometers eliminate measurement errors caused by the user’s hand pressure thanks to their ratchet mechanisms, delivering reliable and repeatable results.
Micrometer Types and Display Technologies
There are different types of micrometer depending on the measuring application and ease of reading:
1. Micrometers by Display Type
- Mechanical Micrometers: Measure with a resolution of 0.01 mm (one hundredth of a millimetre). They work by aligning the graduations on the thimble.
- Digital Micrometers: Offer a resolution of 0.001 mm (one thousandth of a millimetre / 1 micron). Their display allows fast, error-free reading.
- Micrometers with Digital Counter: Although mechanical in design, the counter mechanism on the frame allows hundredths to be read instantly; with the help of the vernier graduations, they allow measurement to a resolution of one thousandth (0.001 mm).
Micrometer Types by Application
- Outside Micrometers: Used to measure the external dimensions of parts, wall thicknesses and shaft diameters.
- Inside Micrometers (Two-Jaw): Preferred for verifying the internal diameters of tubes or the internal distance between two surfaces.
- Three-Point Internal Micrometers (Holtest): Thanks to carbide anvils positioned at 120 degrees, they form a circular plane inside the bore and provide internal diameter measurement with 1 micron accuracy. With extension pieces fitted, taper or roundness checks can be carried out in deep bores.
- Gear Tooth and Sheet Metal Micrometers: Thanks to their special anvil designs, they are used for pitch/root measurements of module gears and for quickly reading sheet metal thickness on a large dial.
- Depth Micrometers: Designed with interchangeable rods to measure precise step and hole depths.
Points to Observe for Precision Measurement
- Using the Ratchet Mechanism: Excessive pressure should not be applied directly to the thimble during measurement; the measurement should be completed using the ratchet mechanism, which provides a constant force of approximately 50 grams.
- Temperature and Calibration: For measuring instruments to give accurate results to standard, an ambient temperature of ideally 20°C is recommended. Measuring accuracy should be checked periodically with gauge blocks (Johansson gauges).
- Using a Micrometer Stand: A micrometer stand should be preferred for precision measurements requiring both hands or at series-production inspection points. This allows one hand to hold the part while the other operates the ratchet comfortably.
For high-precision micrometer solutions and technical details suited to your machining and quality control processes, visit our website temak.com.tr and get support from our team of experts.