How To Choose Nails & Screws

Table 6 provides a listing of the different styles of screw heads that are available along with the features of each.

Table 6 - Screw Heads
Appearance	Name	Features
	Bugle	Common in wood screws as it provides for excellent countersinking in soft and medium soft woods and is generally the head used for drywall.
	Flat	Provides for a head that ends up flush with the surface of the wood.
	Pan	The flat bottom of the pan head screw provides for excellent grip in metal to metal fastening without the need for a large protruding head. Common application is steel stud to steel track fastening.
	Round Washer	The addition of an integral washer stops the screw from countersinking when fastening soft woods.
	Trim	Used for trim and casings when you need a screw that will countersink into the wood easily.
	Round	A general purpose screw head. Used when the screw head is visible.

Table 7 provides a listing of the different styles of screw shanks that are available along with the features of each.

Table 7 - Screw Shanks
Appearance	Name	Features
	Course	The best grip in soft and medium soft woods.
	Fine	Has excellent holding grip in hardwoods and light gauge metal.
	High / Low	Most common application is for drywall screws. This thread does not strip easily when being driven into metal or wood.
	Twin-lead	Designed for faster installation, yet provides excellent grip and does not strip easily.

The length of a screw is measured from the widest point of the head to the tip of the screw point, as shown in Figure 3

how to measure screw length

Table 9 provides a listing of the different styles of screw drives that are available along with the features of each.

Table 8 - Screw Points Wood As Holding Material
Appearance	Name	Features
	Sharp	Most common point for wood screws. Easy penetration in most soft and medium soft woods and other materials.
	Spade	The sharper point on the spade helps the screw to start and penetrate harder materials.
Metal As Holding Material
	Winged	The winged point provides a "drill" as the point of the screw allowing for easier penetration into hardwood and light metal.
	Pilot	Prevents screw jacking when attaching wood to metal.
	Self Drilling	The use of a self drilling point usually eliminates the need to pre-drill a pilot hole in the material.
	Type 1	The advantage of a type 1 point is that it produces a machine gauge thread which allows for the replacement of the screw with a machine bolt.
	Type 17	Cuts a thread through the wood as it is threading into the metal.