How to choose a hardness tester
By Grant, Inspection Tool Specialists. Reviewed November 2026.
Three questions decide which hardness tester you need: what the material is, whether the part can come to a bench or the tester must go to the part, and which hardness scale your drawing, standard or customer asks for. Metals, rubber and plastics each use different instruments, and a tester that is right for one is useless on the other.
What are you testing?
| Material | Scale usually specified | Instrument type |
|---|---|---|
| Steel, cast iron, alloy steel, heat-treated parts | HRC, HB, HV, HL | Leeb or UCI portable tester; Rockwell, Brinell or Vickers bench machine |
| Aluminium, copper and brass | HRB, HB, HW (Webster) | Bench machine, or a Webster tester for quick checks on aluminium sections |
| Rubber, conveyor belt covers, tyres, soft plastics | Shore A | Shore A durometer |
| Hard plastics, hard rubber, resins | Shore D | Shore D durometer |
| Foam, sponge, gels | Shore OO, Shore C | Shore OO or C durometer |
| Fibreglass, composites, soft aluminium | Barcol | Barcol impressor |
| Minerals and stone | Mohs | Mohs hardness kit |
Metals: portable or bench?
If the part can be brought to a bench and your specification names Rockwell, Brinell or Vickers, a bench machine is the direct answer: it tests in the scale specified, with no conversion. Choose portable when the part is too large or heavy to move, is already installed, or you need to test many parts on the shop floor quickly.
Leeb (rebound) testers
Leeb testers fire a small impact body at the surface and measure the rebound. They are quick, inexpensive and good for large, heavy parts: castings, forgings, shafts, plate and heavy sections. They need mass under the test point, so they are unsuitable for thin material, small parts and thin-walled tube unless the part is coupled to a heavy support. Readings in HL are converted to HRC, HB or HV in the instrument, and the conversion is an approximation, so if a customer audits your results against a bench scale, say so in your procedure.
UCI (ultrasonic contact impedance) testers
UCI testers press a Vickers diamond into the surface under a fixed load and measure the change in a vibrating rod's frequency. They work on thin and small parts, welds and heat-affected zones, and need far less mass than Leeb. They are commonly used for Vickers (HV) checks on installed pipework or welds, where a bench test would need a sample cut out. Check that your procedure or specification accepts a UCI result before you rely on it. UCI testers cost more than Leeb.
Bench machines
- Rockwell is a common workshop method for heat-treated steel: quick, direct reading, HRC and HRB scales. Manual machines are the lowest-cost route to a result in those scales.
- Brinell uses a large ball and high load, so it averages over coarse structures. It suits castings, forgings and soft to medium steels, and is often specified for those materials.
- Vickers and micro-Vickers use a diamond pyramid and low loads for thin sections, case depths, platings, coatings and small parts, and are commonly used in laboratories.
- Universal machines combine Rockwell, Brinell and Vickers in one frame, for laboratories and heat-treatment shops that must report in whichever scale the customer asks.
Rubber and plastics: which Shore scale?
Shore durometers press a spring-loaded indenter into the material. The scale is chosen to put the reading in the middle of the range: if a Shore A reading is above about 90, move to Shore D; if a Shore A reading is below about 20, move to Shore OO. For conveyor belt covers, tyres, seals and most moulded rubber, Shore A is the usual choice. Specify a test stand if you need repeatable readings for quality records, because hand pressure varies from one operator to the next.
What accuracy and features do I need?
- Calibration test blocks in the scale you use, so you can check the instrument before each batch and show the check in your records.
- Scale conversion on portable testers: confirm the instrument converts to the scale your customer reports in.
- Memory, printing and data output if readings go into inspection reports.
- Probe options on Leeb and UCI testers for curved surfaces, bores and confined spaces.
- Standards: Leeb testing is described in ASTM A956 and ISO 16859, UCI in ASTM A1038, Rockwell in ISO 6508 and ASTM E18, Brinell in ISO 6506 and ASTM E10, Vickers in ISO 6507 and ASTM E92, and Shore in ISO 868 (plastics), ISO 7619-1 (rubber) and ASTM D2240. Check which one your specification cites before you buy.
Which tester should I buy?
| Application | Suggested starting point |
|---|---|
| Conveyor belts, rollers, seals, moulded rubber | AS-120 Shore hardness tester or digital Shore A durometer 1804-1035 |
| Hard plastics and hard rubber | digital Shore D durometer 1804-1045 |
| Foam and very soft materials | Shore OO durometer TS-OO |
| Large steel parts on site, tight budget | THL210 portable Leeb tester or MH180 portable Leeb tester |
| Large steel parts, records and printing | MH320 Leeb tester or MH660 with printer |
| Welds, heat-affected zones, thin and small metal parts on site | SU-300H UCI tester or SU-410D motorised UCI tester |
| Aluminium sections and extrusions | AW-20+ Webster hardness tester |
| Fibreglass and composites | HBa-1 digital Barcol tester |
| Workshop Rockwell testing of heat-treated steel | HR-150 manual Rockwell tester or DigiRock industrial QC Rockwell |
| Laboratory testing in several scales | DigiRock BRV2 universal tester and the universal hardness range |
As a guide to our current range, including VAT: Shore durometers from about R2,500 upwards; portable Leeb testers from about R9,000 to R27,000; UCI testers from about R92,000; manual Rockwell machines from about R29,000; universal machines from about R75,000 upwards. Prices change, so check the product pages.
Questions we will ask you
Tell us the material, the size and mass of the part, the hardness scale and range your specification names, whether testing is on site or in a workshop, and whether results must be recorded. With that we can recommend a tester and provide pricing.