Tait T860 Series II, Service Manual

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A2.2 Mechanical
M860-00-Preliminary
30/06/98 Copyright TEL
2.2 Pozidriv & Philips Recess Head Screws
Pozidriv and Philips recess head screws will continue to be used in T800 Series II equip-
ment in a few special applications. It is important that you use the correct type and size
screwdriver for each screw type to avoid damaging the screw head.
It is particularly important that you do not use Philips screwdrivers on Pozidriv screw
heads as the tapered driving flutes of the Philips screwdriver do not engage correctly
with the parallel-sided slots in the Pozidriv screw head. This can result in considerable
damage to the screw head if the screwdriver tip turns inside the recess.
Note: If you find you need excessive downwards pressure to keep the screwdriver
tip in the Pozidriv screw head, you are probably using the wrong type and/
or size screwdriver.
Figure 2.2 below shows the main differences between typical Pozidriv and Philips screw
heads and screwdriver tips (actual hardware may differ slightly from these illustrations
due to variations in manufacturing techniques).
Figure 2.2 Pozidriv & Philips Screw & Screwdriver Identification
driving flutes with
parallel sides
driving flutes with
tapered sides
Pozidriv Philips
internal notches
"star" markings
between slots
no special markings
slots with parallel sides
slots with tapered sides
ridges between
driving flutes