Hobeca eLearning Module 8 Care of Measuring Instruments

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Mitutoyo: Module 8
Care of Measuring Equipment

LOOKING AFTER AND USING MEASURING TOOLS
Select a measuring tool that best meets your requirements.

 Check and be sure of the part feature to be measured, then determine the
graduation or resolution, measuring range and accuracy that fully meets your
requirement.

Never engrave, etch or stamp precision measuring instruments.
 This will lead to forfeiting any warranty claims as the manufacturer is unable
to control the conditions under which this takes place.

Do not subject the measuring tool to harsh impacts or shock.
 Be careful not to drop or hit the tool – do not use calipers as a hammer or twirl
your micrometer.

Measuring accuracy is susceptible to dirt/dust.
 The higher the measuring accuracy is required, the more you have to take
care against foreign particles on the tools and work-pieces.

After use, wipe away adhering dust / dirt, finger prints or other contaminants with a
dry cloth.

 To ensure a long service life for your tool, be sure to clean it after use, so you
can successfully start measurement again at a later date.

It is not advisable to use such precision measuring tools as vernier caliper,
micrometer and dial indicators to measure forged rough-casts or abrasive-bearing

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pieces because the measuring faces will be abraded and accuracy will be
compromised

 Check surface of anvils from time to time to ensure no scratches etc affecting
accuracy.

Take measures to prevent rust if storing the tool for an extended period of time, or oil
it as necessary.

 Rust is an enemy of precision measuring tools. It will adversely affect
measurements and spoil the tools. If storing the tool for a long period of time,
take measures against rust by applying an anti-corrosive oil thoroughly
(except for carbide tip) with a cloth soaked in the oil.

Be aware of the workshop environment

 Precision measuring tools should never be put near a magnetic area, such as
a magnetic worktable, to avoid being magnetized.

Maintain temperature.

 Temperature does have a substantial impact on the measuring results.
Precise measurement of work pieces should be carried out only under the
condition that the temperature is around 20°C. Generally, measurements can
be carried out under room temperature, but the work pieces and the
measuring tools should share the same temperature. Otherwise, the result of
measurements will not be accurate due to the characteristic of distortion of
metals subject to temperature changes. Precision measuring tools are subject
to the changes of temperature, too. They should not be put under direct
sunshine, because measurements will not be achieved when the temperature
rises. Never put precision measuring tools near heat sources such as an
electric cooker or heat transmitter to protect the tools from being distorted by
heat, thus affecting accuracy.

Always use recommended batteries.

 Cheaper batteries – although they may have the same voltage – usually last
for a much more limited time due to power requirements of the instruments. If
cheaper batteries are used, the internal chip in the instrument is often
damaged causing batteries to last a very limited time (often only days)
whereas they should last for years.

 USE SR44 Batteries Mitutoyo Code #938882. DO NOT USE LR44 Batteries

So you should observe the following for safe-keeping your tools:

 Avoid exposure to direct sunlight

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 Choose a storage place that is not exposed to high temperatures, low
temperatures or high humidity.

 Do not store in dusty places.
 Do not place tools directly on the floor.
 Store tools in their case where possible.
 Never put precision measuring tools together with hand tools, such as cutting

tools, files, hammers and drills for the fear of bumping the precision
measuring tools.

Periodic maintenance should be applied to precision measuring tools.

 Most precision measuring instruments should be serviced and accuracy
checked at least once a year but if used frequently then six-monthly check
should be done.

 Long-used precision tools should be sent to authorized calibration facilities
periodically for test and calibration to avoid product quality

For Calipers

If you take care of a vernier caliper, it will give you many precise measurements.
In fact, the vernier caliper has a wide range of uses. The jaw shape and scale
location make this tool more adaptable than a micrometer.

The accuracy of a vernier caliper depends on how well you have cared for it.
This is true no matter what type or size caliper is used.
The fit of the sliding jaw and the wear and distortion of the measuring surfaces both
effect the accuracy of the caliper.

Care of the Sliding Jaw

The sliding jaw should fit so it moves easily but without any play.
You can adjust it by taking off and bending the gib in the sliding jaw assembly.
The gib holds the sliding jaw against the blade.
The gib uses just the right pressure to give the jaw proper friction.

Care of Measuring Surfaces

Wear on the jaws of the vernier caliper is mostly at the tips. That's where most
measurements are made.

You can take up some of this wear by adjusting the vernier scale itself.

This scale is mounted with screws in long holes.

This kind of mounting lets you make small adjustments to make up for wear and
distortion.

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Errors, either in parallelism or flatness, must not be exceed 0.005mm. If larger
errors exist, the caliper should be sent to the manufacturer for repair.
Check for wear on the jaws by measuring rolls or rings of known sizes.

 Do NOT engrave an identification mark or other information on a digital caliper
/ digital instrument with an electric marker pen or engraver.

 Wipe scale on new calipers before use to remove protective film.
 Keep the graduations and markings on all calipers clean and readable.
 Wipe away dust and dirt from the sliding surfaces and measuring faces with a

dry cloth before using or storing the caliper.
 Protect the caliper points from damage.
 Avoid damaging the scale of a digital caliper.
 You can clean the measuring surfaces of the jaws by gripping a sheet of clean

paper between the outside jaws and then slowly pulling it out.
 Close the jaws and ensure that the vernier scale (or display) reads zero

before using the caliper.
 When using a digital caliper, reset the origin (ORIGIN button) after replacing

the battery.
 After using a caliper, completely wipe off any water and oil. Then lightly apply

anti-corrosion oil and let dry before storage.
 Wipe off water from a waterproof caliper as well, because it may also rust.
 Store each caliper in its own container, provided with the caliper.
 If a digital instrument will not be used for more than 3 months, remove the

battery before storage.
 Do not leave the jaws of a caliper completely closed during storage.

For Micrometers

Micrometers can make measurements that must be very precise. They are more
reliable and more exact than calipers.

Standard metric micrometers can measure distance to the nearest 0.010mm or .001”
for imperial models.

Some micrometers have an additional scale. These micrometers can measure
distance to the nearest 0.001mm or .0001” for imperial models.

To make sure a micrometer stays accurate, you must take good care of it.

All the parts must be in good condition for the micrometer to work accurately.

Good care includes proper storage, care, and handling.

Care and Handling

In addition to using proper storage methods, you must follow some rules of good
care and handling.

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 Wipe new micrometers before use to remove protective film.
 Keep all graduations and markings clean and easy to read.
 Before you use a micrometer, wipe it off. Then pull a piece of paper between

the anvil and the end of the spindle.
 The micrometer should work freely with no play in its travel. Abuse or uneven

wear can cause play or binding.
 Check the micrometer screw now and then with a measuring standard

normally supplied with the micrometer.
 Never roll the thimble along the hand or arm. Do not hold the thimble and twirl

the frame to open or close the micrometer. This could cause excessive wear
on the screw.
 When the faces of the spindle and anvil become worn, they may no longer be
flat and parallel. This can cause errors in parallelism and give inaccurate
measurements.
 Do not close the spindle and anvil fully when storing a micrometer – always
leave them separated slightly.

If you follow these rules, your micrometer should keep giving you precise
measurements.

For Depth Micrometers

The rules for taking care of a depth micrometer are almost the same as for an
outside micrometer. To take good care of your depth micrometer, follow these rules:

 For storage, coat the micrometer lightly with oil to prevent rust.
 Always store the micrometer in its own container, provided by the

manufacturer.
 Keep all graduations and markings clean and easy to read.
 The micrometer should work freely with no play in its travel. Abuse or uneven

wear can cause play or binding.

For Dial & Digital Indicators

 Do not lubricate the spindle. Doing so might cause dust to accumulate,
resulting in a malfunction.

 Do not subject indicator to harsh impacts or shock.
 Do not disassemble or modify the instrument.
 With digital indicators, do not press the buttons with a pointed object (such as

a screwdriver).
 Take care not to use indicator in environment where it can be sprayed with

coolant.
 Secure the indicator with a fixture such as a dial gauge stand or magnetic

base for a vibration-free environment.
 Clean by using a soft cloth that is dry or moistened with a diluted neutral

detergent. Do not use organic solvents such as thinners.
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