53505/A-U
53505/C-U
53505/D-U
Our durometers are practical and compact instruments that allow quick and accurate checks, both in test laboratories and on-site in any environment.
They are supplied with a checking gauge to verify durometer adjustment and come in a wooden case along with the gauge and user instructions.
They can also be supplied with a maximum reading needle upon request.
Shore hardness measures a material’s resistance to damage or firmness. The measurement principle is as follows: a penetrator is pressed into the test material with a defined force. The deformation at the pressure point is measured, and this determines the material’s hardness value.
Penetration hardness is inversely proportional to penetration and depends on the material’s modulus of elasticity and viscoelastic properties. The shape of the indenter, the applied force, and the application duration influence the results.
Therefore, different material types require different scales, each with specific loading conditions and indenters based on the sample to be tested.
Shore hardness is determined by measuring the penetration of the durometer tip, which operates under spring force, into the sample. The operator must apply the durometer onto the sample with sufficient, consistent contact force without abruptness. The contact force must be strong enough for the durometer’s base (usually an 18 mm diameter disk) to make full contact with the surface, exceeding the spring force to prevent interference.
For each Shore scale, the application force is standardized:
To avoid operator errors due to application force, a durometer stand can be used to ensure exact force application for each scale.
Readings may decrease over time due to the resilient nature of rubber and plastics, so measurements should always be taken after a fixed time, typically 3 seconds. Temperature also affects results – colder materials generally appear harder – so it must be recorded in the test report.
Samples should have a minimum thickness of 6 mm so the indenter can fully penetrate without interference from the hard base. Thinner samples can be stacked to reach 6 mm, though results may be slightly lower. The sample surface should allow at least 5 measurements, spaced 12 mm apart and away from edges.
Shore durometers are designed for flat surfaces. Measurements can be taken on small or irregular pieces, but results will be less accurate.
For curved surfaces such as printing rollers or fruits, tilt the durometer on its axis and record the highest reading. A Maximum Reading Needle is useful for these cases, as it locks the peak value on the dial.
Durometers must be calibrated absolutely, not by referencing. Calibration involves measuring parameters such as the force applied by the indenter throughout its range and the exact shape of the indenter tip. The values must comply with ISO 868, DIN 53505 (Europe), and ASTM D 2240 (USA) standards.
Baxlo provides each durometer with a full calibration certificate and offers quick, cost-effective recalibration services. Reference calibration using certified rubber blocks is acceptable for some applications where high accuracy is not critical, but it is not recommended and does not meet standard requirements (e.g., ISO 9000 quality systems).
The checking gauges supplied with the durometer are only valid for checking tip wear. They are not suitable for calibration under any circumstances.
This is a list of basic mistakes when performing hardness tests manually:
Errors from improper positioning and incorrect force can be avoided by using a durometer stand to ensure correct force and perpendicular alignment.
Below is an approximate conversion table for the main Shore hardness scales. It is based on empirical observations and should only be used as a rough reference. Accurate results can only be obtained by measuring with the correct scale for each material.
| Shore A | 5 | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 100 | ||||||||
| Shore B | 6 | 18 | 27 | 36 | 47 | 56 | 66 | 76 | 85 | 100 | |||||||||
| Shore C | 9 | 14 | 20 | 29 | 38 | 47 | 60 | 77 | 90 | 100 | |||||||||
| Shore D | 6 | 8 | 12 | 16 | 21 | 29 | 40 | 58 | 60 | 70 | 80 | 90 | 100 | ||||||
| Shore 0 | 10 | 15 | 28 | 42 | 53 | 60 | 70 | 75 | 84 | 100 | |||||||||
| Shore 00 | 10 | 20 | 30 | 43 | 55 | 70 | 80 | 86 | 90 | 93 | 95 | 98 |
instruments of
measurement and precision
Pso. Sanlley, Block 6, Nave 2
SUDESTE Industrial Park
08213 POLINYÀ (Barcelona) – SPAIN