Stanley MB05, User Manual

MB05 User

 Manual ◄ 19

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 keep the tool shank lubricated every 

two (2) to three (3) 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 the one in the fatigue failure. The other parts of 

the broken surface are brittle. These failures work slowly 

through the steel until it suddenly parts completely.
The second form of failure caused by surface damage 

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.

Tool bits are made and heat treated to specification.

Tool bits, however well made, are wear parts, and are 

used in the most destructive applications. Even when 

the hydraulic breaker is used properly, and the operator 

is an experienced one, a tool bit may become damaged. 

When a tool bit has been damaged, it is useful to de-

termine 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 point. This 

is part of the learning experience.
Listed below are several methods to determine tool fail-

ure 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 ham-

mer to be concentrated on the tool retainer(s) and the 

retainer slot(s) 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 bushing(s) 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. Call your dealer for acceptable wear allow-

ances.
Worn-out retainer pin(s) will cause uneven loading on 

the pin(s) themselves, causing failure of the tool or re-

tainer pin(s). This will also cause excessive wear to the 

front bushing(s).

PROPER CARE OF TOOL BITS