While screws, nails, bolts, nuts, and combination fasteners are the work horses of construction, sometimes they need a little help. A simple, circular disk applied between your mounting surface and your fastener may be just the trick. Here are five ways you can use washers in your work.
To Distribute Tensile Load. When applying torque to a screw as it enters a material, you create the opportunity for brinelling (permanent indentation into a surface). To prevent this, a plain washer can be used to spread out the load. This is especially useful when installing insulation or foam on interior walls.
To Prevent Friction. When two materials are designed to move in opposing directions, as in robotics, the two oppositional parts making contact can create friction and damage both materials. If a flat washer is introduced between the two, it can reduce the likelihood of friction.
Electrical Insulation. Plastic or ceramic washers can be used to reduce conductivity of nuts and bolts used in electrical related construction.
To Prevent Galvanic Corrosion. When two dissimilar metals connect they can have a chemical reaction that can lead to corrosion. This is particularly true with steel screws contacting aluminum surfaces. Using a washer to separate them can eliminate this issue. The washer must be a non-conductive material.
To Prevent Loosening. Loosening of your fastener can be caused by several factors. If the surface you are fastening to vibrates, this can cause your fastener to slowly release its hold. In this case, a spring washer can be used. They are designed with a slightly cupped shape that exerts pressure over the contact edges of the washer. The pressure assists in keeping the hold strong.
Many people assume a split ring washer is the ideal piece to prevent vibrational or dynamic loosening. However, these rings are only useful if the material they are against is somewhat malleable and the exposed ends can gain purchase within it to increase friction. This is also true of locking washers with serrated edges that may prevent loosening depending on the bearing surface.
When NOT to use a washer: When your hole is too big for your fastener. You are reducing the likelihood of a successful hold because the washer is designed to be supported by the material it is laid against. Less material under the washer, less security of the hold.
Washers can help you get the most out of your construction by distributing the load the fastener is intended to bear. Now, FASCO America® has developed a Washer System to work in conjuction with its pneumatic installer. It works with three types of washers that can be used in lathe and plaster installation as well as building wrapping and foundation insulation. Watch the video to see how it works.