Telescopic Gauge

About Telescopic Gauge

Telescopic gauges are precision measuring instruments used to determine the internal diameter of holes, bores, grooves, and recesses. Also known as telescopic bore gauges, these mechanical tools feature spring-loaded telescoping plungers that expand to contact internal surfaces. Once the measurement is captured, the gauge is locked in position, removed from the bore, and measured using a micrometer or Vernier calliper to determine the exact internal dimension. MyToolShed.co.uk stocks professional-grade telescopic gauge sets from trusted brands including Draper and Sealey.

Unlike digital measuring instruments, telescopic gauges offer a tactile, mechanical approach that many experienced engineers prefer for their reliability and independence from batteries or electronics. They're particularly valued in harsh workshop environments where electronic devices might be vulnerable to contamination, impact, or temperature extremes. Most professional sets include six pieces covering bore diameters from approximately 8mm to 150mm, providing comprehensive measurement coverage for workshop and site applications.

Applications

Telescopic gauges are essential precision tools used across various trades and industries:

• Precision Engineers: Measuring bore sizes in machined components, checking tolerances, and quality control inspections
• Motor Mechanics: Measuring engine cylinder bores, bearing housings, and transmission components during rebuilds and diagnostics
• Machinists: Verifying internal dimensions of turned and machined parts against engineering specifications
• Agricultural Mechanics: Inspecting wear in hydraulic cylinders, pivot pins, and bearing housings on heavy machinery
• Tool and Die Makers: Precision measurement of die cavities, jig bushings, and tooling components
• Quality Control Inspectors: Checking manufactured components meet dimensional specifications in production environments
• Maintenance Engineers: Assessing wear and clearances in industrial machinery, pumps, and equipment

Choosing The Right Telescopic Gauge

Measurement Range: A comprehensive 6-piece set typically covers bore diameters from 8mm to 150mm, suitable for most general engineering and automotive applications. Consider the typical bore sizes you'll be measuring before purchasing.

Build Quality: Professional-grade gauges from brands like Draper and Sealey available at MyToolShed.co.uk feature hardened steel contact points, smooth spring mechanisms, and reliable locking systems. Quality construction directly affects measurement accuracy and tool longevity.

Contact Point Design: Spherical or radiused contact points provide better surface contact and more consistent measurements than flat ends. Ensure all contact points are smooth and unmarked for accurate readings.

Storage Case: A proper fitted case protects gauges from damage, contamination, and corrosion whilst keeping the set organised and clearly identifying each gauge size.

Frequently Asked Questions

How accurate are telescopic gauges?

When used correctly with a quality micrometer, telescopic gauges can achieve accuracy within 0.01mm to 0.02mm. Accuracy depends on user technique and the quality of both the gauge and the micrometer used for final measurement.

What size set do I need for automotive engine work?

A standard 6-piece set covering approximately 8mm to 150mm handles virtually all automotive applications, including cylinder bores, bearing housings, valve guides, and transmission components for most car, van, and light commercial vehicle engines.

How do I use a telescopic gauge properly?

Compress the plungers and insert the gauge into the bore. Release the lock to allow spring-loaded plungers to expand against the bore walls. Rock the gauge gently to find the true diameter, tighten the lock knob, then carefully remove and measure with a micrometer or calliper.