Washer Materials & Shapes
Washers are made from virtually any metallic or non-metallic
material that can be stamped; including low and high
carbon steels, steel alloys, copper, phosphor bronze,
titanium, aluminum, fibre, mica, mylar, rubber, nylon,
teflon, phenolic and many more. I.D. and O.D. can be
configured to provide
any size and shape required. They can be round, square, rectangular,
hexagonal, oval, or non-symmetrical. They can also have tabs, crowns,
notches, and may be countersunk in a variety of degrees.
Washers: Function & Cost
Commercially produced flat washers are designed to meet
the needs of most applications relative to dimensional
tolerances, hardness and surface conditions. Just about
any special need can be met, but it should be remembered
that the closer the tolerance, the greater the cost.
Wherever possible, avoid specifying close tolerances
or variations not warranted by the application.
Washer Plating
If it is necessary that a washer be finished by the
application of a coating such as cadmium, zinc, nickel,
anodize, silver or gold, the correct required finish
should be clearly defined to avoid unnecessary expense.
If commercial plating thickness is acceptable, it should
be so noted. If a special thickness or a post finish
is required, it should be clearly described and specified
as such.
Washer Hardness
Wherever possible, specify commercial quality, low carbon
steel. This generally meets most application needs in
the most economical manner. Only
specify tempered material if special hardness is critical to the application.
Tempers such as 1/4 or 3/4 hard in steel are more difficult to obtain
and, therefore, more costly.
Burrs on Washers
In the manufacturing process, small stamping burrs are
produced. A “normal”
stamping burr is defined as 10% of stock thickness, but not less than
.0005". If this is acceptable, the drawing or specification should
state “normal stamping burrs acceptable”. One method normally
used to reduce stamping burrs is tumbling or vibratory deburring. While
this will not completely eliminate burrs, the process smooths and reduces
the protrusions. Costly “burr free” specifications on prints
should be avoided, if possible.
Surface Finish of Washers
Wherever possible, accept the surface condition of the
material from which the washer is stamped. To meet a
specification for a smoother surface finish
may require such costly secondary operations as grinding or lapping.
Washer Hardness Tolerance Range
As a general cost saving rule, keep tolerances as broad
as possible. Specify,
for example, a Rockwell “C” 45-50 rather that a Rockwell “C” 47-48
wherever it is acceptable. Case hardening tolerances should not be deeper
that necessary (0.003" to 0.005" deep file hard is considered
adequate for most applications).
Washer Ordering Quantities
There is an inverse relationship between quantity and
price: the larger the production quantity, the lower
the unit price. For economy, order the largest quantity
possible. WCL may then schedule economical shipments
of your parts in increments based on your anticipated
needs and usage, rather than making a single delivery.
View, download, or print the PDF file: Washer Facts |
WCL
stocks one of the nation’s most comprehensive lines
of plastic fasteners and components. These are reliable,
high-performance plastic products from the nation’s
leading manufacturers. With our state-of-the-art information
retrieval system, we can immediately tell you, not only
if we have the part you require, but everything else
in stock that’s similar to what you need. We know
the advantages and limitations of commercially used plastics
and plastic compounds. We can assist in developing an
application-specific, cost-effective part matched to
your exact requirements. For the right fastener
at the right price, it’s WCL.