To use a cotter pin, first make sure the pin’s diam-
eter is correct for the hole in the fastener. After cor-
rectly tightening the fastener and aligning the holes,
insert the cotter pin through the hole and bend the
ends over the fastener (
Figure 7
). 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-clips
Snap rings (
Figure 8
) are circular-shaped metal
retaining clips. They secure parts and gears onto
shafts, pins or rods. External type snap rings are
used to retain items on shafts. Internal type snap
rings secure parts within housing bores. In some ap-
plications, in addition to securing the compo-
nent(s), snap rings of varying thickness also
determine endplay. These are usually called
selective snap rings.
Two basic types of snap rings are used: machined
and stamped snap rings. Machined snap rings (
Fig-
ure 9
) can be installed in either direction since both
faces have sharp edges. Stamped snap rings (
Figure
10
) are manufactured with a sharp edge and a round
edge. When installing a stamped snap ring in a
thrust application, install the sharp edge facing
away from the part producing the thrust.
E-clips are used when it is not practical to use a
snap ring. Remove E-clips with a flat blade screw-
driver by prying between the shaft and E-clip. To in-
stall an E-clip, center it over the shaft groove, and
push or tap it into place.
Observe the following when installing snap
rings:
1. Remove and install snap rings with snap ring pli-
ers. See
Snap Ring Pliers
in this chapter.
2. In some applications, it may be necessary to re-
place snap rings after removing them.
3. Compress or expand snap rings only enough to
install them. If overly expanded, they lose their re-
taining ability.
4. After installing a snap ring, make sure it seats
completely.
5. Wear eye protection when removing and install-
ing snap rings.
SHOP SUPPLIES
Lubricants and Fluids
Periodic lubrication helps ensure a long service
life for any type of equipment. Using the correct
type of lubricant is as important as performing the
lubrication service, although in an emergency the
wrong type of lubricant is better than none. The fol-
lowing section describes the types of lubricants
6
CHAPTER ONE
7
Correct installation
of cotter pin
8
Internal snap ring
Plain circlip
External snap ring
E-clip