The Type 17 point helps the screw start into timber, the milling shank clears material as it is driven, and the ribbed countersunk head is designed to seat into the timber surface rather than remain proud.
The different parts of our Impact Professional Wood Screws are intended to help the fixing start, travel through the timber and finish neatly at the surface.
The Type 17 point is designed to start readily in timber. Behind it, the milling shank helps clear material as the screw is driven. At the top, the ribbed double countersunk head is intended to seat into the timber rather than remaining prominently above the surface.
These features are used across the John George Impact Professional screw range. For example, the 5.0 x 75mm Impact Professional Wood Screw is hardened steel with a zinc and yellow passivated finish, a Pozi recess, milling shank and Type 17 point. The 75mm version has a 40mm threaded section.
The point is designed to reduce the need for pilot drilling in many timber applications, although the supplied guidance still notes that a pilot hole can be sensible close to board ends or in particularly dry timber.
Other lengths using the same general fixing design can be compared under screws, fixings and fasteners.