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Page 16
From time to time, we get complaints from customers regarding galling of stainless steel fasteners.
Here is an excerpt from the Industrial Fastener Institute's Standards Book:
Thread galling seems to be the most prevalent with fasteners made of stainless steel, aluminum,
titanium and other alloys which self-generate an oxide surface film for corrosion protection. During
fastener tightening, as pressure builds between the contacting and sliding thread surfaces, protec-
tive oxides are broken, possibly wiped off and interface metal high points shear or lock together.
This cumulative clogging-shearing-locking action causes increasing adhesion. In the extreme, galling
leads to seizing - the actual freezing together of the threads. If tightening is continued, the fastener
can be twisted off or its threads ripped out.
During minor galling, the fastener can still be removed, but in severe cases of galling, a strong bond
between the bolt and nut can prevent removal of fasteners. Unfortunately, little is known on how to
control it, but here are two ways to minimize this effect:
Decreasing installation RPM speed will cause less friction and decrease heat generation.
Lubrication
used prior to assembly can dramatically reduce or eliminate galling. Recommended lubricants should
contain higher amounts of molybdenum disulfide, such as graphite which is very commonly used as
a solid lubricant or special anti-galling lubricants sold by chemical companies.
We provide an anti-seize compound stick called “Thread Magic” (shown in picture below) with all of
our antennas and
strongly encourage
you to use it to reduce the aggravation of galling. The
Thread Magic stick is fantastic—you can get plenty of anti-seize on the fastener without getting it on
your hands!
Contrary to popular belief, galling of stainless steel is not a symptom of a "cheap" fastener - it is
prevalent in all types of stainless steel, aluminum and titanium fasteners. You can be assured that
the stainless steel fasteners we provide with our products are manufactured of very high quality.
A WORD ABOUT STAINLESS STEEL GALLING
PREAMBLE