Eye bolts are commonly the first rigging fitting used in an assembly to lift
or suspend a load. Whether it be attaching in the wood post, steel tubing
or directly in the threaded holes. We'll show you how to select and install the
right one for your application. There are four main styles of eye bolts available
in a variety of sizes and finishes: Regular, Shoulder, Lag, and Machinery.
The size designation for eye bolts are common across all types.
For example, this is a 1/2" x 6" shoulder eye bolt and here is a 1/2" x 6" stainless
steel lag eye bolt. The 1/2" measurement reverences the diameter of
the shank and the 6" measurement refers to the length of the shank.
The larger the diameter of the shank the larger the working load and the longer
shank length will allow you to go through thicker objects. The threaded
portion varies for each eye bolt. So, visit our website if you need more
detailed dimensions of our eye bolts. Another indicator for how strong or
durable an eye bolt will be is the way the eyes manufactured. While most of our
eye bolts come standard with a drop forged eye, we do offer more economical
variants that use formed eyes, however, for critical applications drop forged or
cast eyes are what is recommended. We offer eye bolts in stainless steel,
hot dipped galvanized steel, and self colored finishes. Stainless steel is the
most corrosion resistant and has the best-looking finish.
Hot dip galvanizing provides good corrosion resistance, but with added strength.
Self colored eye bolts are uncoated and designed to be painted by the end-user.
Please see our coatings video on our website and linked in the
description below for more information on coatings and material types.
Regular and shoulder eye bolts can be used to lift her support and overhead load and
each has a working load limit. These fittings are very versatile and designed
to be inserted through a hole and secured on the backside with the
provided nut. Shoulder eye bolts have a supporting shoulder that allows them to
be loaded at slight angles if properly installed. Regular eye bolts don't have a
shoulder and they're designed for straight-line loading only and can bend
and break if loaded at angles. Machinery eye bolts have short fully threaded
shanks that are designed to be screwed directly into threaded or tapped holes.
These fittings have a shoulder allowing for lifting at slight angles and a
listed working load limit. Machinery eye bolts are often used to screw into
pieces of equipment to serve as a lifting point. Lag eye bolts have threads
designed to screw into wood. They don't have a working load limit because their
strength is dependent upon the species and condition of the wood it is screwed
into. For example, a lag eye bolt will hold more load when screwed into a new
oak board compared to an old pine fence post. It is important to note that eye
bolts are designed to be loaded with the axis at the center of the eye. They
should never be loaded perpendicular to that axis because they are likely to
bend and possibly break. Often times loads are applied to eye bolts at an angle and
for these types of applications shoulder eye bolts should only be used.
Angles are important because they can alter the working load limit of the eye
bolt. As you can see here, the cable is at zero degrees. At zero to five degrees the
eye bolt is rated at 100% of its working load limit. In this case the catalog
working load limit of this 3/8 inch machinery eye bolt is 1,550 pounds.
However, if we move to 15 degrees, the working load
limit is reduced by 20 percent making the effective working load limit
of the eyebolt 1,240 pounds which is eighty percent of the original rated capacity.
Moving it to 30 degrees makes for a 65 percent capacity.
45 degrees equals 30percent and
90 degrees equals 25 percent.
At 90 degrees, the 75 percent reduction in capacity makes the effective working load limit only 388 pounds.
So, as you can see, the degree of angle can have a big effect on the working load limit of the eye bolt.
Our website has a table which indicates the angles and effects they have on working load limits
Because of the effect that angles have on eye bolts and working load limits,
we recommend using swivel hoist rings as an alternative choice.
The advantages of using swivel hoist rings over eye bolts is that they maintain 100% the working load limit
at any angle from 0 to 90 degrees, and you can find these
types of fittings on our website. To properly install regular type and
shoulder type eye bolts, first, determine the thickness of what the eye bolt will
be attaching to. Then, choose an eye bolt with a shank that is long enough so that
its threads will protrude from the backside and allow the nut to be
tightened properly. If the unthreaded portion of the shank protrudes below the
bottom surface and does not allow the nut to be tightened
you can use washers to fill the space of the unthreaded portion of the shank.
Machinery eye bolts are primarily intended to be installed in a tapped holes.
The eye bolts are threaded to UNC standard and as such the hole needs to
be tapped accordingly to ensure the shoulder will be firmly seated against
the object to be lifted. When drilling and tapping the hole for the eye bolt,
the hole depth should be the length of the shank plus 1/2 the diameter of the
shank. As mentioned earlier, eye bolts are to be used so that loads are applied
about the axis of the eye. When installing machinery eye bolts, it may be
necessary to add washers to shim the eye bolt to achieve the correct alignment.
Today, we'll illustrate this by attaching for machinery eye bolts to each corner
of this lifting box and we'll attach a four leg bridle assembly to each of the
eye bolts. Note that all the eye bolts are not in line. To correct this we're
going to add washers as needed to get the eye bolts into the inline position as shown here.
Now that we've covered the types of eye bolts available and installation basics
here are some general safety precautions that you
should be aware of. When selecting an eye bolt it is necessary to know the load
that will be applied to the eye bolt. If you're uncertain of the load it is
recommended to choose a larger sized eye bolt to be on the safe side.
Always take into consideration the working load limit of the object to which you are
fastening the eye bolt to as this will affect the working load limit of your
entire rigging assembly. Always inspect eye bolts before use and never use an
eye bolt that shows signs of wear or damage. Always be sure the threads on the
shank and receiving holes are clean, and never machine grind or cutting an eyebolt.
Never rig a sling or cable from one eye bolt to the other as shown here.
We hope this video has helped you with the selection and installation of
eyebolts for your rigging assembly. If you have any further questions please
feel free to contact us on our website and please subscribe to our YouTube
channel for more information on various rigging topics.
I'm Tyler with E-Rigging thanks for watching.