Typical Length Measurements for Building Fasteners
Just as buildings come in all shapes and sizes, Building Fasteners and even Marine Fasteners or Line Fasteners are also manufactured in many different shapes and sizes. There are standard measurements used in common applications as well as the ability to create customized fasteners for almost any application.
How Is Fastener Length Calculated?
The length of a fastener is measured from the tip to the where the surface material is assumed to be. That means that a building fastener that is meant to be countersunk will be measured from the top (which will be flush with the surface) to the tip.
In contrast, the length of screws with a head that will sit above the surface are measured from the bottom of the head to the tip of the screw or bolt. Some common building fasteners measured in this way are:
- pan head screws
- round head screws
- carriage bolts
- lag bolts
- truss head sheet metal screws
- hex head bolts
- socket head caps
How Do You Know Which Length to Order?
The length and design of the fastener ordered will depend largely on the material being ordered and the application. When building wood framing for a structure or flooring the screws and bolts needed will probably be specified by the building codes. A good rule of thumb is to be sure the fastener will penetrate the wood at least 1 to 1 1/2 inches (assuming that this length won’t penetrate through the wood).
If the fastener is too long it could result in split wood and if they are too short the project will not hold together.
When dealing with steel the length of the fastener will often be determined by the thickness of the steel and the nut required to complete the attachment. In many applications a good rule of thumb is to ensure that only one thread touches the steel. There also needs to be enough thread extending past the steel to hold on the nut and possibly a washer.
If you are in doubt about the length required and the applicable building codes don’t help, contact a fastener distributor or manufacturer for some guidance. Remember that the total length is based on where the surface of the material is and be sure to account for a nut and washer when working with steel.
About the Author
Started my career in the fastener world in 1969 at, Parker Kalon Corp. a NJ based screw manufacturer located in Clifton, NJ working in inventory control, scheduling secondary production and concluding there in purchasing. In 1971 I accepted a sales position at Star Stainless Screw Co., Totowa, NJ working in inside sales and later as an outside salesman, having a successful career at Star I had the desire with a friend to start our own fastener distribution company in 1980 named: Divspec, Kenilworth, NJ. This was a successful adventure but ended in 1985 with me starting Melfast in August 1985 and have stayed competitive and successful to date. Melfast serves the OEM market with approximately 400 accounts nationally.
