Hand-Held Hardness Tester
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SH-21A Ultrasonic hardness tester SONOHARD®

The SH-21A is very easy to use and requires no special knowledge of hardness testing in order to operate the instrument. The unit includes all four hardness scales and you can switch between them at the touch of a button.

Quick measurement (few seconds)
Best repeatability and precision
Direct reading of hardness
Easy to use hand held probe can be quickly applied to a variety of surfaces from any direction.
Easy to use - no prior experience of hardness measurement techniques required.
Built in memory for data and calibration points.
Measures Vickers, Rockwell, Brinell and Shore scales.
Interchangeable probes for use with different surface profiles, pipes, concave surfaces, gears valves etc.
Portable works with rechargeable lithium ion battery.

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  • Evaluation of carburizing, standard quenching and high-frequency quenching
  • Weld hardness measurement for welded structures (tanks, hulls, bridges, steel towers ,etc.)
  • Hardness measurement for a gear tooth flank (narrow area)
  • Measurement of structural strength or hardness of a facility
  • 100% online inspection for components (engine valves, rack bars, crankshafts, bearings, etc.)


Measuring Indenter Diamond indenter for Micro-Vickers (facing-to-surface angle of 136 deg)
Measuring load Approx 1kgf (roughly 10N)
Approx 2kgf (roughly 20N)
(These loads indicate those in typical applications. As the specification varies according to the object to be measured, please contact us for details.)
Measuring range Rockwell hardness: 10.0 HRC to 70.0 HRC
Vickers hardness: 100 HV to 999 HV
Shore hardness: 20.0 HS to 99.9 HS
Brinell hardness: 85 HBW to 550 HBW
Reproducibility HRC:± 1.0HRC , HV : ± (3%rdg)HV , HS: ± 1.0HS , HBW : ± (3%rdg)HBW
Power source AC adapter (100 to 240V) or lithium ion rechargeable battery
Minimum target size 15 mm (width) x 15 mm (length) x 7 mm (thickness)

Measuring Stand (option)

Measuring Stand

When mounted on the measuring stand, the tester can be used as a stationary hardness tester.
This compact, lightweight checker (2.5kg) can be carried around on-site.


Measurement Principle

The Ultrasonic hardness tester model SH-21A differs completely from traditional hardness testers. Instead of measuring the size of the indentation of the test sample using a microscope, it uses a diamond indenter equipped with a vibrating rod that presses on the test surface at a fixed load and then measures its hardness by applying ultrasonic vibrations and analyzing its damping effect. When the vibration rod is applied to a soft-surfaced test sample with identical qualities and at a fixed force, it makes a deep indentation and gets locked into the groove. Due to this, the resonance frequency increases. Conversely, it does not get locked in when used on hard test samples and the resonance frequency drops. The test sample's hardness can be calculated using the correlation between this deviation and the tested hardness.

Measurement principle diagram

Measuring Stand

Thickness Gauges and Hardness Testers

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