Yellow Spring (0-20N)

Replacement Yellow Spring (0-20N) for Hardness Test Pencil: Simple, compact and easy to use Hardness Test Pencil. The estimated or known spring tension is set with the help of the slider. Holding the instrument upright and placing its point on the test surface one draws a 5 to 10 mm long line at a rate of approximately 10 mm/sec. The stylus should produce a scratch which is just visible to the naked eye. If the spring pressure is too high, the scratch is clearly visible; if too low, no scratch appears. The applied pressure, fixed by locking the slider is marked in Newtons. Also available: Blue Spring (0-3N) Red Spring (0-10N) Test Tip 0.5mm Test Tip 0.75mm Test Tip 1mm