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What
maintenance is required?
All
bearings and gears in Taber Shear / Scratch Testers are grease
lubricated and sealed at the factory. If properly stored and handled,
this precision instrument does not require regular maintenance.
To
ensure your test results are accurate, Taber recommends that you
have your instrument calibrated on an annual basis.
What size specimens can be tested?
The
instrument can test flat materials up to 1/2" thick x 4"
square or round.
What is the advantage of a motorized turntable?
A
motorized turntable ensures a constant rate of shearing / scratching
action, and provides greater accuracy in test results.
Can you adjust the scale beam to ensure it is level with the
specimen and turntable?
The
scale beam is mounted on a pivotal shaft projecting from an adjustable
gage block. This gage block can be raised and lowered, permitting
the scale to be raised or lowered to correspond with the thickness
of the test specimen.
What do the graduations on the scale beam represent?
The
engraved graduations represent 10 grams per division. The sliding
weight provides an adjustment in load from 0 to 500 grams. An
additional calibrated weight is also furnished for attachment
to the end of the beam to increase its load capacity to a total
of 1000 grams.
Is one shear cut (or scratch) enough to evaluate?
Taber
recommends three to four shear cuts at least ½" in
length, made on the specimen surface approximately 90° to
120° apart from each other with a width ranging between 0.050"
to 0.100". Due to the difficulty in cutting grooves of identical
width, minor deviations can be compensated for by averaging the
measurements.
My test results are not consistent?
For
reproducible tests, it is recommended the operations be performed
under conditions covered by a test specification, such as width
of groove, temperature, humidity, age of specimen material, etc.
Any of these items can influence the shear resistance of organic
materials.
An
irregular or jumpy cut not caused by careless test procedures,
may be indicative of non-uniform composition or surface irregularities.
On surfaces such as these, the instrument may not provide useful
test data.
When should I replace the Diamond Tool?
Over time, the diamond tools will wear out. Due to material differences, there is no way to predict how long the tool will last. Taber recommends that an extra tool is kept on hand for standardization purposes. We also offer the Diamond Standardization Plate which can be used to perform the standardization procedure referenced in test method ISO 4586-2.
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