Technical Manual
Installation and Operation
© SPECTRA ENGINEERING 2022 Revision 1.0.0
9
2.2 Screw Head Types
Modern screws employ a wide variety of drive designs, each requiring a different kind
of tools to drive in or extract them. Spectra Engineering has chosen the
Pozidriv
®
screw head and screwdriver as it preferred screw type on all of its products, sizes 1 &
2. This is because the Pozidriv system is the choice for high volume assembly
operations. It provides self-centring system and excellent driving control with less
operator fatigue.
It is similar to the classic Phillips cross-head. The differences lie in the way that the
heads are machined. The Phillips head has 4 simple slots cut out of it, whereas in the
case of the Pozidriv each slot is the result of two machining processes at right angles.
The result of this is that the arms of the cross are parallel sided in the case of Pozidriv,
and tapered in the case of Phillips. The Pozidriv has four additional points of contact,
and does not have the rounded corners that the Phillips screw drive has.
Phillips screwdrivers will usually work in Pozidriv screws, but Phillips screwdrivers
are likely to slip or tear out the screw head when used in Pozidriv screws. It is
important that you use the correct type and size screwdriver to avoid damaging the
screw head.
Exrta contact points
Figure 1-1 Top view of screw heads
Pozidriv
Philliips
Parallel sides
Tapered sides
Figure 1-2 Side View of screw Heads
Exrta contact ridges
Parrallel driving flute
Tapered driving flute
Figure 1-3 Screw driver Tip View
Used on All
Spectra products
Don’t used this type
on Spectra products
Pozidriv
Phillips