Pole line fasteners often require an added semi-cone point on the threaded end. This eases entry into the pre-drilled holes in the wooden members that they are going through. Not all pole line fasteners have added semi-cone points, however. The common items that have an added semi-cone point are hex head machine bolts, square head machine bolts, washer head bolts, double end bolts and double arming bolts. Although it can differ depending on who manufactures them, the length of the semi-cone point is approximately 1/2 of the diameter of the bolt. In other words, a 1/2″ diameter machine bolt will have a 1/4″ added semi-cone point on the end and a 1″ diameter machine bolt will have a 1/2″ added semi-cone point.
An important thing to keep in mind when specifying a particular length of bolt is that the semi-cone point length is not included in the overall bolt length call out. For example, if a 1″ x 18″ long square head bolt is required, it is called out as 1″ x 18″, not 1″ x 18-1/2″, though the total length of the bolt (including the point) will be 18-1/2″. Double end bolts and double arming bolts have an added semi-cone point on each end. Double arming bolts will sometimes have a 1/4″ semi-cone point added to each end regardless of the diameter of bolt, but more often than not, each semi-cone point would be 1/2 of the diameter.