KAH Operation & Maintenance Guide
Page: 65 of 88
Krueger | 1401 N Plano Rd | Richardson, TX 75081 | 972.680.9136 | [email protected] | www.krueger-hvac.com
SECTION 4 - SERVICE & REPAIR
Standard Mounting
1. Install the shaft key. If a key was furnished with the
bushing, use that key.
2. Install the bushing on the clean shaft, flange end first.
If the bushing will not freely slide onto the shaft, insert
a screwdriver or similar object into the flange sawcut
to act as a wedge to open the bushings bore.
3. If using the set screw, tighten it enough to prevent the
bushing from sliding onto the shaft.
4. Slide the sheave into position on the bushing, aligning
the drill holes in the sheave with the tapped holes in
the bushing flange.
5. Loosely thread the caps crews with the lock washers
into the assembly.
Reverse Mounting
1. With large end of the out, slide the sheave onto the
shaft as far as possible. Install the shaft key.
2. If a key was furnished with bushing, use that key.
3. Install the bushing onto the shaft so that the tapered
end will mate with the sheave.
4. If using the set screw, tighten it enough to prevent the
bushing from sliding onto the shaft.
a. Pull the sheave up onto the bushing, align the
drilled holes in the bushing flange with the tapped
holes in the sheave.
b. Loosely thread the cap screws with lock washers
into the assembly.
Using a torque wrench, tighten all the cap screws evenly
and progressively in rotation to the torque value as
shown in Table 16 (right). There must be a gap between
the bushing flange and sheave hub when installation is
complete.
Adjusting Sheave
1. Before belts are installed, check alignment as
described in Section 4.
2. If adjustment is required, measure the space between
the straight edge and the sheave.
3. Follow steps 2 through 5 under Removing Sheave in
this section. Move the bushing in the proper direction
the distance measured.
4. Proceed with the instructions in Installing Sheave in
this section.
5. Tighten all set screws according to the values in Table
17 (right).
CAUTION -
Excessive wedging will split the
bushing.
Do not tighten the set screw to standard torque
values at this time.
Do not use the lubricant on the cap screws.
CAUTION -
Do not over torque. Do not attempt to
close the gap between the bushing flange and the
sheave hub.
CAUTION -
The tightening force on the screws is
multiplied many times by the wedging action of
the tapered surface. If extreme tightening force
is applied, or if a lubricant is used, bursting
pressures will be created in the hub of the mating
part.
TAPERED
BUSHING
SIZE AND THREAD
OF CAP SCREW
FT-LB TO APPLY WITH
TORQUE WRENCH
QT
1/4 X 1
9
JA
NO. 10-24
5
SH-SDS-SD
1/4-20
9
SK
5/16-18
15
SF
3/8-16
30
E
1/2-13
60
F
9/16-12
110
J
5/8-11
135
TABLE 16 - CAP SCREW TORQUE VALUES
SET SCREW
DIAMETER
HEX WRENCH
SIZE ACROSS
FLATS
MIN. RECOMMENDED TORQUE
IN-LB
FT-LBS
1/4
1/8
66 - 85
5.5 - 7.08
5/16
5/32
126 - 164
10.5 - 13.7
3/8
3/16
228 - 296
19.0 - 24.7
7/16
7/32
348 - 452
29.0 - 35.7
1/2
1/4
504 - 655
42.0 - 54.6
5/8
5/16
1104 - 1435
92.0 - 119.6
TABLE 17 - SET SCREW TORQUE VALUES
