Economical, quick, and easy to operate the James Instruments’ Roll Hardness Tester provide mill, converter, or printing company technicians a quick check for common roll defects. Three units are available, W-D-555, digital unit, W-M-355, recording unit, and the W-M-255, manual unit. These non-destructive testing instruments profile paper, film, and foil rolls across the spectrum of industrial processes.

All the units operate by determining the hardness of the material being tested. The impact plunger of the instrument is pressed against the paper roll which compresses a spring. After reaching a certain point, the spring is released and an internal hammer is launched. The amount of hammer rebound depends on the hardness of the test piece, this amount is then shown on a scale of 10 to 100. Test intervals of 2” (50mm) to 4 (100mm) have been found sufficient.

Digital W-D-1505

Manual Test Hammer W-M-355

The W-M-355 Recording Test Hammer gives you the same quality as the W-M-255 but with the added feature of a built-in automatic chart recorder. Every test you take is automatically recorded as a bar chart on a paper strip. This creates a field record to verify your findings. In addition to this paper record, you can see each test as it happens through the large easy to read window. The W-M-355 comes with two rolls of paper, each with a capacity to record over 4000 tests.

Manual Test Hammer W-M-255
	The W-M-255 Manual Test Hammer is the traditional instrument used for the non-destructive testing of roll hardness. This easy-to-use instrument provides a quick and simple test for obtaining an immediate indication of concrete strength in various parts of a structure.