NT 505 Adjustable Pencil Hardness Tester is designed according with ASTM D 3363,ISO 15184.Operator can obtain three different weights（500g,765g and 1000g）through selecting different loading weight.

Main Technical Parameters
■ Three points are touched on the tested surface（roller, pencil core）
■ The angle between pencil and the tested surface is 45º
■ Pressure of pencil lead is 500g,765g,1000g
■ Ordering Information：
    NT 505----Adjustable Pencil Hardness Tester
Test Procedure

a)Prepare substrate according to GB/T9271《Paints and varnishes - Standard test panels》.
b)Remove approximately 5mm to 6mm of wood from the point of each pencil, being careful to leave an undisturbed, unmarked, smooth cylinder of pencil lead. The tip of the lead shall be squared by holding the pencil in a vertical position and moving the pencil back and forth over abrasive paper, maintaining an angle of 90℃. Continue until a flat, smooth, circular cross-section is obtained, free from chips or nicks in the edge. Repeat this procedure each time a pencil is used.  
c)Carry out the test at a temperature of (23±2)℃ and a relative humidity of (50±5)%, unless otherwise agreed.
d)  Insert a pencil as figured, push the test panel at a speed of 0.5 mm/s to 1 mm/s for a distance of at least 7mm. The hardness of the hardest pencil which does not occur marking over a distance of at least 3mm is the so-called pencil hardness. 
e)  Carry out the test in duplicate. If the two results differ by more than one unit of pencil hardness, discard them and repeat the test.