4.1 The resistance of a species of wood or a wood-base product to direct withdrawal of nails, staples, or screws is a measure of its ability to hold or be held to an adjoining object by means of such fasteners. Factors that affect this withdrawal resistance include the physical and mechanical properties of the wood; the size, shape, and surface condition of the fasteners; the speed of withdrawal; physical changes to wood or fasteners between time of driving and time of withdrawal; orientation of fiber axis; and the occurrence and nature of prebored lead holes.

4.2 By using a standard size and type of nail, staple, or screw, withdrawal resistance of a wood species or wood product can be determined, and such values for two or more wood species or wood products can be compared. Throughout the method this is referred to as the basic withdrawal test. Similarly, comparative performances of different sizes or types of nail, staple, or screw can be determined by using a standard procedure with a particular wood or wood product, which eliminates the wood or the wood product as a variable. Since differences in test methods can have considerable influence on results, it is important that a standard procedure be specified and adhered to, if test values are to be related to other test results.