SPI - Standard Test Blocks


  • Standard test blocks provide and easy means of checking your tester's accuracy.
  • Periodic testing on a regular basis is recommended.
  • Comparing a test reading of the block with the hardness number on the test block will indicate whether or not the instrument needs attention.
  • A surface rating of less than 5 micro‐inches (CLA), and both test and supporting surfaces flat and parallel prior to being calibrated.
  • Order the hardness range and scale which is approximately the same as the work you will be testing.
  • Approximate sizes: 1 1/2"L x 2 1/2"W x 1/2"H.
SKU Description Hardness Scale Each
12-535-1 SPI Hardness Test Block - 20-30 HRC Scale - Type: C 20-30C
12-536-9 SPI Hardness Test Block - 35-55 HRC Scale - Type: C 35-55C
12-537-7 SPI Hardness Test Block - 60-70 HRC Scale - Type: C 60-70C
12-538-5 SPI Hardness Test Block - 80-88 HRC Scale - Type: A 80-88A
12-539-3 SPI Hardness Test Block - 85-95 HRC Scale - Type: B 85-95B
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