GENERAL INFORMATION
1-12
specifications. Poor quality or damaged Phillips
screwdrivers can back out (cam out) and round over
the screw head. In addition. Weak or soft screw
materials can make removal difficult.
The best type of screwdriver to use on Phillips
screw is the ACR Phillips II screwdriver, patented by
the horizontal anti-cam out ribs found on the driving
faces or flutes of the screwdriver’s tip (
figure 4
). ACR
Phillips II screwdrivers were designed as part of a
manufacturing drive system to be used with ACR
Phillips II screws, but they work of tool companies offer ACR Phillips II screwdrivers in different Tip size
and interchangeable bits to fit screwdriver bit holders.
NOTE
Another way to prevent cam out and to increase the
grip of a Phillips screwdriver is to apply valve grinding
compound or permute screw
＆
socket Gripper onto
the screwdriver tip. After loosening/tightening the screw,
clean the screw recess to prevent engine oil
contamination.
Wrenches
Open-end, box-end and combination wrenches
(
figure 5
) are available in a variety of types and sizes.
The number stamped on the wrench refers to the
distance of the fastener head.
The box-end wrench is an excellent tool because
it grips the fastener on all sides. This reduces the
chance of the tool slipping. The box-end wrench is
designed with either a 6 or 12-point opening. For
stubborn or damaged fasteners, the 6-point provides
superior holding because it contacts the fastener
across a wider area at all six edges. For general use,
the 12-point works well. It allows the wrench to be
removed and reinstalled without moving the handle
over such a wide are.
An open-end wrench is fast and works best in
areas with limited overhead access. It contacts the
fastener at only two points and is subject to slipping if
under heavy force, or if the tool or fastener is worn. A
box-end wrench is preferred in most instances,
especially when braking loose and applying the final
tightness to a fastener.
The combination wrench has a box-end on one end and an open-end on one end and an
