Kreg K3 Instructional Manual page 20

Selecting the Correct Screw
19
Kreg self-tapping screws are specially designed for pocket hole joinery. They feature a
self-tapping auger point that eliminates pre-drilling and a large round head that seats flush
in the bottom of the pocket hole. All of our screws utilize a #2 square drive recess. The
deep recess of the square drive provides positive driver engagement to reduce cam-out.
Like every Kreg product, our screws are manufactured from the highest quality materials.
To manufacture a virtually unbreakable screw, industrial quality steel is first case-hardened
and then coated with a dri-lube finish which reduces driving torque and gives them their
bronze appearance. Many of our screw types are available in a weather resistant coating
that is approximately 10 times more corrosion resistant than a standard zinc plated screw.
Choosing the right screw...
We offer three thread types, two head styles and five different lengths to handle nearly
all pocket hole applications. The characteristics for choosing the screw for your project are
detailed below.
Thread Types
A fine-thread screw is used any time you're driving the screw
into a hardwood (i.e., oak, maple, walnut, cherry, hickory, etc.)
The coarse-thread screw has a larger thread diameter and
provides greater holding power when driving a screw into soft
material such as plywood, particle board, MDF, melamine, and
pine. We also offer a Hi-Lo thread type which consists of two
separate threads, one higher than the other that serves as a
general purpose screw in medium hardwoods like poplar. The
Hi-Lo screw is only offered in the 1-1/4" length.
Head Styles
The washer head (SML) screw is our most popular head style as
it provides the largest amount of surface area to seat firmly
in the bottom of the pocket. Available in both fine or coarse
thread, this head style is highly recommended if the material
the pocket is drilled into is soft such as plywood or pine. The
large washer head assures that the screw is not overdriven in
the bottom of the pocket.
The second available head style is the pan head (SPS). The pan
head is slightly smaller in both head and shank diameter than
the washer head screw and is a good alternative to the washer head screw if both mating
workpieces are made of extremely hard woods. The pan head style is also of benefit in the
1" length as it allows one to join 1/2" and 5/8" stock and easily seat the screw head below
flush.
Screw Length
There are five thread lengths most commonly used in pocket hole joinery; 1", 1-1/4",
1-1/2", 2", and 2-1/2". Choosing the correct screw length depends on the setting of your
jig and the depth at which you drill the pocket hole. Both of these standard setting can be
viewed on the previous pages.
Fine
Coarse
Hi-Lo
Maxi-Loc
Head
Pan
Head