The Chain adaptor hardness tester is a complement to the Brinell PHB-3000 hardness tester. Brinell PHB-3000 hardness tester at the beginning of the design due to the overall design structure of the limit, the height of the opening and throat depth is fixed, so the size of the test workpiece requirements are limited, the diameter of the round rod can only be tested up to diameter 200mm. For bars larger than 200mm in diameter, if you want to test any point on the surface of the circle, you can only think of other methods. Based on the Brinell PHB-3000's core hydraulic system test head, the technician came up with the idea of replacing the PHB-3000 frame with a chain adapter for hardness testing of round rods with diameters of more than 200mm. This change expands the range of PHB-3000 applications. The standard length of the chain adapter hardness tester chain is 1.5 meters, and the maximum diameter that can be measured is about 550mm. Depending on the design of the chain adapter, the maximum length of the chain can be increased to 2.4 m, and the corresponding maximum diameter can be measured to 850mm. So basically, the Brinell hardness of large diameter tubes can be solved with a combination of Brinell PHB-3000 Tester and chain adapter hardness tester. In practice, many customers buy this combination: a Brinell PHB-3000 and a chain adapter frame, or a chain adapter instrument and a Brinell PHB-3000 frame. Both freely combine to measure different size workpiece. However, it should be noted that the direction of the dial gauge is opposite. When the test head on one instrument is transferred to the other instrument, the indicator reading is in the opposite direction, and another colleague may be required to assist the test.