Hex Head Lag Screws
Lag Bolts, or Lag Screws in various finishes for any application
Lag bolts, also called lag screws, are basically "large wood screws". A typical lag bolt is a 6 inches long, 1/4 diameter screw with coarse threads of a wood-screw or sheet-metal-screw threadform (but larger).
Lag screws feature an external hex head and come in a variety of corrosion resistant metals. Lag bolts are used to lag together lumber framing, to lag machinery feet to wood floors, and other heavy carpentry applications. These fasteners are clearly "screws" when defined by the Machinery's Handbook distinction. The term "lag bolt" has been replaced by "lag screw" in the Machinery's Handbook. However, in the minds of most tradesmen, they are "bolts", simply because they are large, with external-hex heads. In the United Kingdom, lag bolts/screws are known as coach screws.
18-8 Stainless Steel Lag Screws
Stainless steel is used primarily for long lasting applications, due to its corrosion-resistant nature and durability. Scratching or burring the metal will not create surface rust as the corrosion resistance exists within the metal itself. Stainless steel is a soft metal due to the low carbon content, therefore most stainless steel bolts are cold-formed and not heat treated or thru-hardened. Cold forming and threading causes stainless steel bolts to become slightly magnetic, some fasteners will be more magnetic than others depending on size and how quick the cold forming process is. Stainless steel fasteners are typically a clean silver color, which also makes them common in finishing and decorative applications. Stainless Steel should never be used with aluminum, corrosion may occur.
(18% Chrome, 8% Nickel, .08% Maximum Carbon) – 18-8 Stainless refers to 300 series stainless steel. 303 and 304 Stainless are the most commonly listed grades, the standard grade for stainless steel fasteners. They are corrosion-resistant and durable. They are often used in marine applications in freshwater environments, but will not work as effectively in a salt water environment as 316 stainless. Stainless alloy resists oxidizing and rusting, however it can tarnish over time.
Hot Dipped Galvanized Steel Lag Screws
Hot dip galvanizing is a process that adds a layer of corrosion resistance by dipping fabricated steel into a kettle containing molten zinc. The HDG process creates a tightly bonded alloy for superior corrosion resistance and harsh environment applications. HDG products must be used exclusively when applied, meaning that a plain zinc nut or stainless nut cannot be applied to an HDG bolt.
Silicon Bronze Lag Screws
Silicon bronze fasteners are made of copper, silicon, and various other alloys such as zinc, tin, iron and manganese. Silicon bronze is used in marine environments, corrosive environments, and high heat environments. Often used in plumbing and electrical applications, silicon bronze fasteners are also found on tattoo machines and in power plants. Silicon bronze is similar in color to copper and is sometimes used in finish applications for the color.
Zinc Plated Steel Lag Screws
Zinc plated steel is very common in the fastener industry. Zinc adds a layer of corrosion resistance to plain alloy steel. Clear zinc has a light, shiny color and blue zinc has a bright blue hue. Zinc plated steel is not suitable for extreme environment use, as it is not as resistant to corrosion as hot dipped galvanized.