So you want to protect the eyes in your cable or rope from abrasion but you're
not sure which thimble to choose, I'll teach you everything you need to know to
make a good choice. Thimbles are used to protect the eyes of cable and rope
slings from abrasion, by providing a solid steel barrier between the fragile
cable strands and the other fitting used in the connection. They also prevent
eye deformation or kinking by giving structure to the eye. After repeated high
load use, wear and kinking reduces the strength of the cable, and can lead to
premature failure. Thimbles come in two different duty grades, light duty and
heavy duty. Light duty thimbles are typically used in static applications,
such as a permanent installation, a controlled environment, or in situations
where they won't experience much load. Regardless of application, light duty
thimbles typically work best on traditional fiber rope. You can see here
that a heavy duty thimble is grossly overkill for this application. A light
duty thimble is fine in this case because it can handle the same amount of
rough handling and load as you would expect this fiber rope to take. Because
heavy duty thimbles have extended protective material around their edges,
and a tendency to resist deformation in uncontrolled applications, they're
commonly used in applications that will experience dynamic loading or loads near
or at the working load limit. Situations that require frequent connecting and
disconnecting of rigging components, such as lifting or towing, are perfect
matches for heavy duty thimbles. Our thimbles are made from zinc plated steel,
hot dipped galvanized steel, or type three one six stainless steel. Starting
with our most corrosion resistant, stainless steel thimbles are best suited
for being used in outdoor applications, and are highly resistant to rust.
Stainless steel thimbles are also ideal for being used in or near saltwater
environments, where corrosion frequently occurs and are the best choice when
using stainless steel cable or chain. Our heavy-duty high dipped galvanized
thimbles, come in at a lower cost than stainless steel, and are also suited for
outdoor environments. While galvanized components are also ideal for outdoor
use, galvanized thimbles can exhibit signs of surface rust if the galvanized coating is
worn off on the load-bearing or contact areas of the component. This type
of surface rust is normally worn when loaded or used and shouldn't affect
the components performance. Our light duty zinc plated thimbles can also be
used outdoors, but be aware that zinc plating is thinner than hot dip
galvanizing, so the thimble may exhibit signs of surface rust earlier than a hot
dipped galvanized thimble. This is especially true in environments where
the thimble will be exposed to rain or snow, or in salt air or saltwater
environments. Thimbles can be used in conjunction with cable and rope, the most
important thing with each connection is making sure the thimble is fastened tight
in the eye, and the thimble is sized properly. If the thimble is too loose in
the eye, it can fall out or rotate, and if the thimble is undersized or grossly
oversized, connections to other properly sized rigging fittings can become
difficult. For the best fit, be sure to size the thimble to the
actual size of the item you're using with it. For example, if you're using
quarter-inch uncoated cable, use a quarter-inch thimble. The size of vinyl
coated cable may be confusing, as some manufacturers measure different things. E- Rigging list vinyl coated cable by the cable diameter, and the coating adds a
little thickness. The finished or final diameter is listed on the product pages
on our website. It typically coincides with the next size larger thimble. For
example, 3/16 inch vinyl coated cable is coated to quarter inch diameter, so use a
quarter inch thimble. Stripped vinyl coated cable is sized just like uncoated
cable. If you have a 3/16 inch cable, use a 3/16 inch thimble. Thimbles are often
used with other rigging components with a solid eye and must be open to do so.
You can use a set of pliers to hold onto each side of the thimble, and with a
twisting motion, open the thimble so that the component can be inserted into
the thimble, and then return the thimble to its
normal shape. This process can also be done by hand if the thimble is small
enough, so light-duty thimbles will be best suited for this method. Some
thimbles cannot be bent by using a pair of pliers or your hands, so for larger
thimbles, a vise and pipe is the preferred method.
To recap, the variables to consider for proper thimble selection are duty grade,
size, coating type, and application. If you have any further questions please feel
free to contact us on our website, and please subscribe to our YouTube channel
for any more information on various rigging topics. I'm Tyler Hall with E- Rigging, thanks for watching.