Portable hardness tester specially developed for electro-deposited copper, soft copper and other low hardness materials.
The Webster® Model BB-75 was developed to meet the requirements of industries requiring a fast and reliable method of testing electro-deposited copper and other soft materials.
The BB-75 penetrator is combined with the Model B load spring to provide lighter testing pressure, allowing accurate hardness measurements in the low hardness range that cannot be achieved using the standard B-75 load spring.
This unique combination enables testing of fully annealed copper and many other soft non-ferrous materials while maintaining the portability and ease of use of the Webster® hardness tester.
The Webster® Model BB-75 was developed to answer the need of certain industries for a method of rapidly testing the hardness of electro-deposited copper and copper in the low hardness range.
The B-75 penetrator provides higher sensitivity while the Model B load spring applies a lighter testing force. This combination enables users to accurately measure the hardness of soft copper and many common low hardness materials.
This modification, produced by combining the Models B and B-75, allows users to test soft materials comparable to fully annealed copper, making it ideal for production quality control and laboratory inspection.
Cutaway showing the internal construction of the Webster® Model BB-75 housing assembly.
Zero adjustment can be checked by operating the gauge against the bare anvil. If required, reset the zero by turning the adjustment screw located on top of the dial indicator while the penetrator is fully compressed against the anvil. Normally this adjustment is only necessary after wear of internal components.
Load spring adjustment is used to calibrate the tester against a sample with known hardness. Each tester is supplied with a standard 61ST6 aluminum alloy test block. When the tester is adjusted to obtain a reading of 17 on this reference block, the published hardness conversion curve will be accurately reproduced.
The adjustment is made by removing the handle, lifting the dial indicator from the housing, and using the supplied adjustment wrench to increase or decrease the load spring force.
The chart below illustrates the hardness range covered by the Webster® Model BB-75 on copper. The data was obtained by testing numerous samples with the tester calibrated to read 17 on the supplied 61ST6 aluminum alloy standard block (Rockwell E 90–93).
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