Yamaha MM700A Manual page 11

GENERAL INFORMATION
Correct installation
Specifications for torque are provided in New-
ton-meters (N•m), foot-pounds (ft.-lb.) and inch-pounds
(in.-lb.). Refer to Table 6 for torque conversions and Ta-
ble 7 for general torque specifications. To use Table 7,
first determine the size of the fastener as described in Fas-
teners in this chapter. Torque specifications for specific
components are at the end of the appropriate chapters.
Torque wrenches are covered in the Basic Tools section.
Self-Locking Fasteners
Several types of bolts, screws and nuts incorporate a
system that creates interference between the two fasten-
ers. Interference is achieved in various ways. The most
common type is the nylon insert nut and a
coating on the threads of a bolt.
Self-locking fasteners offer greater holding strength
than standard fasteners, which improves their resistance
to vibration. Most self-locking fasteners cannot be reused.
The materials used to form the lock become distorted after
the initial installation and removal. It is a good practice to
discard and replace self-locking fasteners after their re-
moval. Do not replace self-locking fasteners with stan-
dard fasteners.
Washers
There are two basic types of washers: flat washers and
lockwashers. Flat washers are simple discs with a hole to
fit a screw or bolt. Lockwashers prevent a fastener from
working loose. Washers can be used as spacers and seals,
or to help distribute fastener load and to prevent the fas-
tener from damaging the component.
As with fasteners, when replacing washers make sure
the replacement washers are of the same design and qual-
ity.
Cotter Pins
A cotter pin is a split metal pin inserted into a hole or
slot to prevent a fastener from loosening. In certain appli-
cations, the fastener must be secured in this way. For these
applications, a cotter pin and castellated (slotted) nut is
used.
To use a cotter pin, first make sure the diameter is cor-
rect for the hole in the fastener. After correctly tightening
the fastener and aligning the holes, insert the cotter pin
through the hole and bend the ends over the fastener (Fig-
ure 6). Unless instructed to do so, never loosen a torqued
fastener to align the holes. If the holes do not align, tighten
the fastener just enough to achieve alignment.
Cotter pins are available in various diameters and
lengths. Measure length from the bottom of the head to the
tip of the shortest pin.
Snap Rings and E-rings
Snap rings (Figure 7) are circular-shaped metal retain-
ing clips. They help secure parts and gears in place such as
shafts, pins or rods. External type snap rings retain items
on shafts. Internal type snap rings secure parts within
housing bores. In some applications, in addition to secur-
ing the component(s), snap rings of varying thickness also
determine endplay. These are usually called selective snap
rings.
dry
adhesive Two basic types of snap rings are used: machined and
stamped snap rings. Machined snap rings (Figure 8) can
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