Proper Care Of Tool Bits - Stanley MBF5 User Manual

Tool bits are made and heat treated to specification.
Tool bits are wear parts and are used in the most
destructive applications. Even when the hydraulic
breaker is used properly, and the operator is
experienced, a tool bit may become damaged. When a
tool bit has been damaged, it is useful to determine the
cause immediately in order to prevent the damage from
occurring again.
All STANLEY tool bits are machined and hardened for
maximum performance. Care must be taken to maintain
the tools original condition for optimum productivity and
life expectancy. It is not uncommon for an operator, who
is unfamiliar with using a hammer, to break a bit. This is
part of the learning experience.
Listed below are several methods to determine tool
failure and will quickly aid in warranty determination.
TOOL FAILURE NOT COVERED
UNDER WARRANTY
BLANK FIRING OR FREE RUNNING
This occurs when the tool is not in proper contact with
the work, thus causing the energy produced by the
hammer to be concentrated on the tool retainers and the
retainer slots on the tool itself. Caution should be used
to prevent the hammer from sliding off slanted surfaces
or when breaking through thin material.
The illustration below is typical of the kind of breakage
that occurs from excessive blank firing.
WORN-OUT FRONT BUSHING(S) OR
RETAINER PIN(S)
Worn-out front bushings will cause the tool to become
misaligned inside the hammer. This misalignment will
cause uneven contact between the piston and tool, thus
causing stress to concentrate on one particular area of
the tool. This can also cause the tool to bind inside the
hammer.
Worn-out retainer pins will cause uneven loading on the
pins themselves, causing failure of the tool or retainer
pins. This will also cause excessive wear to the front
bushings.

PROPER CARE OF TOOL BITS

METAL-TO-METAL CONTACT
Extreme caution should be used to avoid scratches or
gouges on the surface of the tool. These areas create a
stress concentration metal-to-metal contact point, thus
weakening the tool.
Another form of metal-to-metal contact is galling, which
usually occurs from the lack of lubrication. Special care
should be taken to lubricate the tool shaft every two to
three hours.
Steel failures that were caused by surface damage take
two main forms. The simplest form is caused by deep
scratches on working steel surface. The broken surface
has a shell pattern around the starting point of failure,
similar to fatigue failure. The other parts of the broken
surface are brittle. These failures work slowly through
the steel until it suddenly fails completely.
The second form surface damage failure occurs when
there are deep scratches on working steel surface and
there was also excessive bending stress. The broken
surface also shows the shell pattern, but the other parts
of the broken surface are brittle and usually have a "lip",
like that in a stress failure.
In extreme cases, the combination of surface damage
and severe bending can quickly break even the best
working steels.
The illustrations below show examples of severe stress
breaks.
MBF5 User Manual ◄ 23