Specialized screws designed primarily to attach wood to wood.
Maximum holding power
Wood screws have an aggressive thread profile designed to maximize the holding power needed to form strong joints in wood. Their low cost and availability make them ideal to attach a variety of non-wood objects to wood (eg hinges, hardware, locks).
Easy to drive.
Wood screws have sharp, coarse, and widely spaced thread and a gimlet point ideal for easy penetration into wood and for tapping their own mating threads during installation. Wood screw have either cut threads or rolled threads, which influences thread and shank diameters. For specifications of thread and body diameters of cut vs rolled threads click here
Many Styles and Materials
Wood screws are available in steel
with the following head styles: flat head, oval head and round head, drives: Phillips drive, square socket drive and slot drive and with either a zinc finish or black oxide finish. Wood screws are also available in stainless steel
with flat head and phillips drive. Sizes range between #2 to> #16 in diameter and 1/4" to 6" in length.
Pre-drilling pilot holes in hard woods is recommended to ensure that splitting of the wood does not occur. For specifications of recommended pilot hole sizes click here
Wood Screw Head Styles Include:
- Round Head: Round Head Machine Screws: The head offers a flat bearing area with a rounded top, often used for decorative purposes. This head style has been largely replaced by other styles.
- Oval Head: Oval head machine screws, often called oval countersunk, have a tapered base similar to a flat head, but with a sightly rounded head that lies slightly above the surface. These are ideal for countersunk holes, where they have a better profile than round head machine screw heads with a little more of a decorative finish than a flat head. Because they are countersunk, they help the machine screw to center. These heads are often combined with countersunk finishing washers for holding thin materials in place without damage.
- Flat Head: Flat head machine screws have a tapered base and a flat surface that sits flush or slightly below the surface when installed and helps the machine screw to center. This require a pre-drilled counter sink - usually angled at 82 degrees (Unified thread). Metric flat heads have 90 degree angles. For a more decorative finish an oval head might be better suited as it has a slightly rounded top that remains above the surface.
Wood Screw Drive Types:
- Slot drive:Slotted drive machine screws have a simple slot, requiring a standard slotted screwdriver bit. The main disadvantage of slotted drives is that the driver bits easily cam out.
- Phillips drive: Phillips drive machine screws reduce camming to some degree. These drives were actually designed to cause the bit to cam out in order to prevent over-tightening.
- Square drive: Square drive machine screws, also known as Robertson drive, have a square recess in the head of the screw. This drive style reduces the risk of camming out, and allows the use much higher torque for tightening. For additional information about the square drive recess including dimensions and technical specifications, click