Yamaha MM700A Manual page 15

GENERAL INFORMATION
and resistant to wear. Their working surface is devoid of
sharp edges and the tool is carefully polished. They have
an easy-to-clean finish and are comfortable to use. Qual-
ity tools are a good investment.
When purchasing tools to perform the procedures cov-
ered in this manual, consider the potential frequency of
use. If starting a tool kit, consider purchasing a basic tool
set from a large tool supplier. These sets are available in
many tool combinations and offer substantial savings
when compared to individually purchased tools. As work
experience grows and tasks become more complicated,
specialized tools can be added.
Screwdrivers
Screwdrivers of various lengths and types are manda-
tory for the simplest tool kit. The two basic types are the
slotted tip (flat blade) and the Phillips tip. These are avail-
able in sets that often include an assortment of tip sizes
and shaft lengths.
As with all tools, use a screwdriver designed for the job.
Make sure the size of the tip conforms to the size and
shape of the fastener. Use them only for driving screws.
Never use a screwdriver for prying or chiseling metal. Re-
pair or replace worn or damaged screwdrivers. A worn tip
may damage the fastener, making it difficult to remove.
Wrenches
Box-end, open-end and combination wrenches (Figure
10) come in a variety of types and sizes.
The number stamped on the wrench refers to the dis-
tance between the work areas. This size must match the
size 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 fasten-
ers, the 6-point provides superior holding ability by con-
tacting 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 arc.
An open-end wrench is fast and works best in areas with
limited overhead access. It contacts the fastener at only
two points, and can slip under heavy force, or if the tool or
fastener is worn. A box-end wrench is preferred in most
instances, especially when breaking loose and applying
the final tightness to a fastener.
The combination wrench has a box-end on one end, and
an open-end on the other. This combination makes it a
very convenient tool.
Adjustable Wrenches
An adjustable wrench or Crescent wrench (Figure 11)
can nearly any nut or bolt head that has clear access
fit
around its entire perimeter. Adjustable wrenches are best
used as a backup wrench to keep a large nut or bolt from
turning while the other end is being loosened or tightened
with a box-end or socket wrench.
Adjustable wrenches contact the fastener at only two
points, which makes them more subject to slipping off the
fastener. The fact that one jaw is adjustable and may
loosen only aggravates this shortcoming. Make certain
the solid jaw is the one transmitting the force.
Socket Wrenches, Ratchets and Handles
Sockets that attach to a ratchet handle (Figure 12) are
available with 6-point (A, Figure 13) or 12-point (B)
openings and different drive sizes. The drive size indi-
cates the size of the square hole that accepts the ratchet
handle. The number stamped on the socket is the size of
the work area and must match the fastener head.
9