Micrometers

About Micrometers

Micrometers are precision measuring instruments designed to deliver accurate measurements down to one-thousandth of a millimetre, making them indispensable for engineering, machining, and quality control applications. MyToolShed.co.uk stocks a comprehensive range including external micrometers for measuring outside dimensions, internal micrometers for bore measurements, and depth micrometers for assessing recess depths. Available in both traditional mechanical versions with vernier scales and modern digital models with LCD displays, the collection features trusted brands including Moore and Wright, Facom, Draper Expert, Sealey, and Sirius.

Digital micrometers offer easy-to-read measurements with instant metric/imperial conversion and data output capabilities, whilst mechanical models provide robust, battery-free reliability preferred by many experienced engineers. Quality instruments feature hardened, ground, and lapped measuring faces for long-lasting accuracy, with measurement ranges typically starting from 0-25mm and extending up to 150mm or more. Most come supplied in protective cases with calibration standards to ensure measurement integrity, making them essential tools for any precision workshop.

Applications

Micrometers are essential measuring tools used by precision-focused professionals across numerous trades and industries:

• Machinists and CNC Operators: Verifying dimensions of turned, milled, and ground components to ensure they meet drawing specifications and tolerances
• Tool and Die Makers: Measuring precision tooling, jigs, and fixtures where accuracy is critical to component quality
• Quality Control Inspectors: Conducting first-off and in-process inspections to maintain manufacturing standards
• Automotive Engineers: Measuring engine components, brake discs, bearing clearances, and critical parts during rebuilds
• Aerospace Technicians: Working to extremely tight tolerances where component accuracy is safety-critical
• Model Engineers and Hobbyists: Building precision miniature engines and mechanical models requiring accurate component manufacture
• Maintenance Engineers: Assessing wear on shafts, bearings, and components to determine service intervals and replacement schedules

Choosing The Right Micrometers

Type of Measurement: Determine whether you need external micrometers for outside dimensions (the most common type), internal micrometers for bore measurements, or depth micrometers for measuring hole depths. Four-piece sets covering 0-100mm provide excellent versatility for general engineering work.

Digital vs. Mechanical: Digital micrometers offer quick, easy-to-read measurements with data output and metric/imperial switching, ideal for high-volume inspection work. Mechanical micrometers with vernier scales require no batteries and are preferred by experienced engineers who appreciate their tactile feedback and robust construction.

Measuring Range: Micrometers are manufactured in specific ranges, typically in 25mm increments. A 0-25mm micrometer is essential for most workshops, but larger components require correspondingly sized instruments or sets covering multiple ranges.

Accuracy and Resolution: Mechanical micrometers typically measure to 0.01mm, sufficient for most engineering applications. Digital models often provide 0.001mm resolution for ultra-precision work. MyToolShed.co.uk stocks premium brands like Moore and Wright and Facom, renowned for their accuracy and build quality, alongside accessible options from Draper and Sealey for general workshop use.

Frequently Asked Questions

What's the difference between a micrometer and a vernier calliper?

Micrometers are more accurate than vernier callipers, typically measuring to 0.01mm or better compared to 0.02mm for callipers. However, micrometers have a limited measuring range (usually 25mm) and are specific to external, internal, or depth measurements, whilst callipers are more versatile tools. For precision engineering work requiring tolerances below 0.05mm, micrometers are the preferred choice.

How often should micrometers be calibrated?

For workshop use, checking calibration monthly using gauge blocks or setting standards is good practice. In quality-critical or ISO-certified environments, annual calibration by an accredited laboratory is typically required. Always re-check zero settings before important measurements and after any impact or suspected damage.

Can micrometers measure in both metric and imperial?

Digital micrometers typically feature instant metric/imperial conversion with the press of a button. Mechanical micrometers are manufactured in either metric (mm) or imperial (inch) formats. In UK engineering, metric micrometers are standard, though some industries working with older equipment may require imperial instruments.