Length of Shank Fastener length is measured from the material's presumed surface to the fastener's end. The measurement for fasteners with heads that typically sit above the surface is from directly under the head to the end of the fastening. Shank length varies by type of material used in manufacture but usually ranges from 4-6 inches for wood, and 5/8-1 inch for metal. As part of its quality control procedure, your local Sears store manager will measure the shank length on a small sample of chairs before they are released for sale to the public. If you have questions about how long the shank will be after it has been installed, ask your store manager when they make their measurements. Shank length can affect which tools can be used to install them. For example, if the shank is too short, then only flathead drivers can be used to drive them into place. However, if the shank is long enough so that it can be threaded, then only Phillips head screws can be used with a screwdriver to drive them in place. The amount of force required to drive a fastener depends on many factors such as type of material, thickness of material, location of installation, etc. But generally, the longer the shank length, the easier it is to drive.