5
CHANGES AND T YPING ERRORS RESERVED
CHANGES AND T YPING ERRORS RESERVED
5.5 r
eplacing
The
indenTer
When the hardness tester cannot be calibrated correctly anymore, the indenter is worn and must be replaced.
• Undo the pivot screw and take out the bottom handle.
• Take out the dial head but leave the cylinder in the frame. You can now see the adjusting nut.
• Loosen the adjusting nut (see also figure 4) and take out the indenter.
• Insert the new indenter and fasten the adjusting nut. Do not fasten the nut too tight as this will damage the
indenter.
• Calibrate the hardness tester as described in paragraphs 5.3 and 5.4.
6. m
ainTenance
This hardness tester is a precision instrument. Its service life depends on correct use and good maintenance.
• Clean the hardness tester every time you have used it with a soft cloth.
• The various parts of the tester have been treated to protect them against rust. However, always check the tester
for rust when you use it often or when you are using it in a damp environment.
• Never drop the hardness tester. This will influence the correct working of the tester and may even render it
useless.
• Do not remove any parts of the tester other than for calibration purposes. Removing further parts voids the
guarantee.
7. f
acTors
ThaT
will
inflUence
The
accUracy
of
The
TesTer
7.1 m
aTerial
The surface of the material to be measured needs to be free of dust and grains to ensure the accuracy of the
measurement.
7.2 d
isTance
To
The
edge
of
The
maTerial
The distance between the tip of the indenter and the edge of the material has to be at least 5 mm. When you
measure closer to the edge this may influence the result.
7.3 d
isTance
beTween
Two
measUring
poinTs
The distance between two measuring points has to be at least 6 mm. When you measure too close to an earlier
measuring point this may influence the result.
7.4 o
xidaTion
Even though a layer of oxidation is thin, it will influence the result of a measurement. A layer of 10 µm will result
in a deviation of 0.5 to 1 HW (over).
7.5 c
oaTing
A coating on the material will give you a unreliable result. Therefore you should always remove any coatings with
sanding paper or a solvent.
7.6 (i
n
)
correcT
Use
• You should check the accuracy of the hardness tester regularly and calibrate it if necessary (see chapter 5).
• Always place the material horizontally between the tip of the indenter and the anvil. Make sure the material
presses well against the anvil.
• Press down the handle firmly in one go. When you add pressure slowly this will result in an inaccurate reading.
• Make sure the material does not shift while measuring.