Rexnord
®
Thomas
®
Disc Couplings
•
Installation and Maintenance
Series 52
•
Sizes 225-750 (Tpack
)
(Page 3 of 4)
Rexnord Industries, LLC, 5555 S. Moorland Rd., New Berlin, WI 53151-7953
538-212
Telephone: 262-796-4060 Fax: 262-796-4064
November 2008
e-mail: [email protected] web: www.rexnord.com
Supersedes CP-Series 52-T, 8-06
TABLE 1A — Set Screw Tightening Torque
Setscrew
Thread Size
Torque
in-lb
Torque
ft-lb
Torque
Nm
1/4-20
66
6
7
1/4-28
76
6
9
5/16-18
132
11
15
5/16-24
144
12
16
3/8-16
240
20
27
3/8-24
276
23
31
1/2-13
600
50
68
1/2-20
660
55
75
TABLE 1 — Locknut Tightening Torques, Dimension “N” Limits and
Suggested Maximum Alignment Values
COUPLING
SIZE
“A”
Diameter
Inch
Dimension “N”
Inch
Axial
Capacity
Inch
Locknut
Alignment Total
Indicator Reading
Thread
Size
Torque
Min
Max
Ft-Lb
(In-Lb)
Nm
(Angular)
Inch
Parallel
Inch
225
5.69
.37
.38
± .036
5/16 - 24
25
34
.006
.001 inc
h per inc
h of
axial
length betw
een flex elements
262
6.63
.48
.49
± .043
3/8 - 24
34
46
.007
312
7.81
.51
.52
± .051
7/16 - 20
60
81
.008
350
8.69
.54
.55
± .056
1/2 - 20
95
129
.009
375
9.69
.60
.61
± .062
9/16 - 18
130
176
.010
425
10.50
.63
.64
± .067
5/8 - 18
175
237
.011
450
11.31
.73
.75
± .072
11/16 –16
150
203
.012
500
12.88
.79
.81
± .082
3/4 –16
190
258
.012
550
14.44
.92
.94
± .092
7/8 –14
255
346
.014
600
16.00
.99
1.01
± .102
1-14
335
454
.016
700
18.25
1.20
1.23
± .115
1-1/8-12
425
576
.018
750
19.81
1.26
1.29
± .125
1-1/4-12
560
759
.020
NOTE:
1. These torque values are approximate for steel bolts with lubricated threads. The locknuts are prevailing torque type
and some resistance will be felt. If galling is suspected, immediately stop and contact Rexnord. Modification will be
necessary for stainless steel. For stainless steel, the tightened torque must be reduced to 60% of the values shown.
Stainless steel bolt and locknut threads must also be liberally coasted with molybdenum disulfide grease.
2. Bolts should be held from rotating while the locknuts are tightened to the values shown.
These locknuts are cadmium plated. Do not use any lubricants other than clean oil noted in Section 6. Consult
Rexnord if unsure.
D.
Now proceed to the other end of the coupling.
Remove the support bolts, if used, and support
the center member in one of the other ways. Using
paragraph “6. C” above install the second disc
pack.
E. Make the final coupling alignment check at this time.
F. Fully tighten the locknuts evenly and in an
incremental and alternating fashion. See Table 1 for
torque values.
NOTE:
With the coupling in good alignment, the
bolts should easily fit through the holes in the
flanges and the disc pack.
It is recommended that all locknuts be retightened
after several hours of initial operation whenever
possible.
G. For further help with the installation or alignment
consult Rexnord.
7.
Disc Pack Replacement —
If it becomes necessary to
replace the disc pack, it can be done as follows:
NOTE: Sizes 225 through 750 use the Tpack
unitized
disc pack. The Tpack
disc pack will replace the
original Thomas round, non-unitized disc pack without
modification to the coupling. Be sure to use the washers
that are supplied with the Tpack
replacement kit.
A. At one end of the coupling remove all locknuts
Support the center member at this end. Back out
and remove the bolts and loose washers. It may
be necessary to tap ends of the bolts with a soft
hammer to start them out. Slide the pack out while
supporting the center member at this end.
B. Now disassemble the other end per “7. A” above,
being sure to support the center member when
taking out the last bolt. Remove the center member.
