Hardness Testers and Durometers
F.A.Q.
What is the difference between Shore A, Shore D, and Shore OO durometer scales?
All three scales comply with ASTM D2240 but use different spring forces and indenter tip geometries to match material stiffness:- Shore OO uses a very light spring force (113 gf) and a spherical Ø 2.4 mm tip for ultra-soft foams, sponges, and gels.
- Shore A uses an 822 gf spring load and a blunt 35° frustum cone for normal soft-to-medium rubbers, elastomers, and soft PVC.
- Shore D uses a heavy 4,536 gf (10 lb) spring load and a sharp 30° cone for hard rubbers (above 90 Shore A) and rigid thermoplastics. When a specimen reads above 90 on the Shore A scale, ASTM D2240 recommends switching to a Shore D durometer; when a Shore D reading falls below 20, switch to Shore A.
Why should I choose an IRHD or Type M tester instead of Shore A for O-rings and thin sheets?
Standard Shore A durometers require a minimum flat specimen thickness of 6 mm (0.24"); on thinner sheets or curved O-rings, the indenter force penetrates through the rubber and senses the hard support table underneath, producing artificially high readings. IRHD Micro Hardness Testers (per ASTM D1415 / ISO 48) and Type M O-Ring Systems (like the Rex OTK-DG paired with the Rex OS-3 Stand) use micro indenters and low forces specifically designed to test materials from 0.030" (0.76 mm) to 5 mm and curved O-ring cross-sections without destructive cutting.
Why is a durometer test stand recommended for ASTM D2240 compliance?
Hand-held durometer readings vary between operators due to differences in pressing force, approach speed, and angular tilt. Mounting your durometer on a constant-load or motorized stand from our Durometer Test Stands subcategory—such as the Imada YMS Motorized Stand, Imada SY Lever Stand, or Rex OS-2H Hydraulic Dampened Stand—applies the exact ASTM D2240 mass (1 kg for Type A/B/E/O, 5 kg for Type C/D/DO, or 400 g for Type OO/OOO) at a controlled descent rate and strictly perpendicular contact angle.
How do I verify durometer accuracy in the field or laboratory?
Per ASTM D2240, durometers should be checked regularly against certified reference blocks to verify spring calibration and indenter condition. ABQ Industrial supplies Rex Durometer Test Block Kits (TBKC Series) with NIST-traceable certificates, Checkline TBK-HP / HP-PT Test Blocks, Hildebrand IRHD Test Block Sets, and the Rex RDC-1 Durometer Calibrator for full in-house spring-force calibration.
Checkline AD-100 Shore Durometer Tester
$539.00 - $589.00
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- Checkline AD-100 Shore Durometer Tester
- Available Scales: A, B, C, D, DO, O, OO & Asker C
- Can be used in any measurement orientation as gravity does not affect readings
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Checkline DD-100 Digital Shore Durometer Tester
$1,293.00 - $1,425.00
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- Checkline DD-100 Digital Shore Durometer Tester
- Available Scales: A, B, C, D, DO, O, OO and Asker C
- Can be used in any measurement orientation as gravity does not affect readings
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Checkline HP Shore Durometers
$622.00
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- Checkline HP Series Shore Durometers
- Available Scales: A, B, C, D, DO & O
- Manufacturer: Checkline
- Warranty: One Year
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Checkline AD-300 Precision Durometer
$825.00 - $875.00
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- Checkline AD-300 Precision Durometer
- Measures according to
DIN 53505 (A, D)
ISO 868 (A, D)
ISO 7619 (A, D)
ASTM D 2240 (A, D, C, O).
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Checkline DD-300 Digital Precision Durometer
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- Highly accurate and repetitive
- Timer function to take measurement after (0-15) seconds
- Conform to DIN ISO 7619-1, ISO 868, ISO 7619-1 and ASTM D 2240
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Checkline Durometer-Fixtures
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- Custom fixtures are available for your specific application
- Manufacturer: Checkline
- Warranty: One Year
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Shore Durometer Selection Guide
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- Choose the ideal durometer for your application
- Manufacturer: Checkline
- Warranty: One Year
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Checkline Durometer Technical Information
Discontinued Product
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- Rubber & Plastic Hardness Tester
- Unique flexible coupling system automatically aligns the presser foot to the surface of sample
- Manufacturer: Checkline
- Warranty: One Year
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Checkline PTS-HP HP Durometer Test Stand
$930.00
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- Checkline PTS-HP HP Durometer Test Stand for HPSA, HPSD or HPSO Durometers
- Spring loaded lever for fast & precise travel
- Manufacturer: Rex
- Warranty: One Year
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Checkline OS-300-2 Durometer Test Stand
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- Checkline OS-300-2 Durometer Test Stand
- Spring loaded lever for fast & precise travel
- Durometer Test Stand designed for use with AD-300 Analog Durometers
- Manufacturer: Checkline
- Warranty: One Year
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Checkline HP Textile Durometer, Yarn Package Durometer Hardness Tester
$611.00
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- Checkline HP Textile Durometer, Yarn Package Durometer Hardness Tester
- Constant-pressure indicating system assures uniform test pressure eliminating false readings due to differences between operators
- Warranty: One Year
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Checkline HPSA-R Durometer
$699.00
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- Checkline HPSA-R Durometer for Nip / Rubber Rollers and Cylindrical Materials
- Operation is as easy as pressing the spring-loaded knurled aluminum shell down to the red line
- Manufacturer: Checkline
- Warranty: One Year
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Checkline HPSAO Shore Durometer
$622.00
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- Checkline HPSAO Shore Durometer
- For use with: foams, steering wheels and inner linings of motor vehicles
- Manufacturer: Checkline
- Warranty: One Year
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Checkline QH2 Portable Leeb Hardness Tester for Steel, Demeq
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Checkline QH5 Leeb Hardness Tester, Rebound Hardness, Demeq
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- Checkline QH5 Leeb Hardness Tester, Rebound Hardness
- Accuracy of ± 4HL (0.5% at 800HL)
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Checkline QH7 Heavy Duty Portable Hardness Tester, Demeq
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- Heavy Duty Portable Hardness Tester
- Available in Leeb, UCI, or both methods in one unit
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Checkline SH-21 Metal Hardness Tester - Rockwell HRC
$6,045.00 - $7,365.00
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- Checkline SH-21 Metal Hardness Tester - Rockwell HRC
- Displays hardness in HV (Vickers), HRC (Rockwell), HS (Shore) and HB (Brinnel) units.
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SH-22A Metal Hardness Tester
$6,595.00
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- Narrow / curved surface can be measured by small diameter probe (compared to the SH-21)
- Tiny indentation (Approx. 0.1mm)
- High durability, rated for over 1 million measurements
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Checkline TBK-HP Test Block for HP Textile Durometers with Flat Base
$215.00
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- Checkline Test Block Kit for Flat Bottom HP Durometers
- Manufacturer: Checkline
- Warranty: One Year
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Checkline HP-TB Test Block for curved bottom HP Durometers
$110.00
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- Checkline HP-TB Test Block for curved bottom HP Durometers
- Manufacturer: Checkline
- Warranty: One Year
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