SAF and SAFS series
WARNING: Read these instructions before starting work. Failure to follow these instructions could result in injury or damage such as catastrophic premature bearing fail- ure. Be careful with heavy weight and tools and other devices, and with high pressure oil when using the hydraulic assist method. Be familiar with the MSDS or other safety instructions for any grease or oil used and keep them nearby.
Step 1
Remove any burrs or rust on the shaft with an emery cloth or a fine file.
Step 2
Wipe the shaft with a clean cloth.
Step 3
Check shaft diameter.
Note: S1 refers to the shaft tolerance for an adapter mounted bearing. S2 and S3 refer to the shaft tolerance under the seal for a cylindrical mounted bearing, not the bearing seat diameter. For bearing seat diameter tolerances, refer to the Shaft and Housing Fits Section of this catalog on page 57.
Step 4
Install inboard seal.
PosiTrac (LOR) and PosiTrac Plus seal Slide the seal onto the shaft. The resistance should only require slight hand pressure to overcome. The O-ring can be lubricated with grease or oil to ease assembly. Locate the seal to match the labyrinths in the hous- ing. The old style LER labyrinth seal still used for small shaft diameters is installed in the same manner. The picture shows the PosiTrac Plus seal, which requires greasing the seal lip at assembly. See PosiTrac Plus Assembly Instructions for more information (Publication 655-810), which is included with the B-10724 contact element. SKF’s next generation M5 style SAF housings have the external labyrinth painted for improved corrosion resistance. Removal of this paint is not recommended.
Taconite (TER) seal
Coat the shaft with oil. Smear grease in the bore of the seal cartridge, filling the cavity between seals, and lubricating the bore of the felt seal and the lip of the contact seal. Fill the TER seal cavity with grease. If the end of the shaft does not have a lead-in bevel, smooth the bore of the felt seal with a flat instrument to aid in starting the felt over the end of the shaft. Carefully slide the seal cartridge assembly on the shaft to approximate assembly position. Note: Make sure the lobes of the rubber extrusion on the outside diameter of the taconite seal are not located at the split of the housing; to ensure this occurs, the grease fitting should
be at 12 or 6 o’clock. For seal misalignment capabilities, see Table 12.
Step 5
Mount the bearing.
Note: Several mounting methods exist. Refer to the beginning of this section for specific mounting instructions for the spe- cific bearing being used in the housing. Please consult SKF for alternative instruc- tions or reference www.skf.com/mount.
Step 6
Install outboard seal (same as step 4).
Step 7
Lower half of housing (Base)
Set the bases on their mounting surface and lightly oil the bearing seats. SKF’s M5 style SAF housings have painted base- planes. Removal of this paint is not required prior to installation. If grease is used as a lubricant, it should be applied before the upper half of the housing is secured. Smear grease between the rolling elements of the bearing and work it in until the bearing is 100% full. The base should be packed 1/3 to 1/2 full of grease. See Table 10 for initial grease fill. For M5 style SAF housings, there is a cast line in the housing base that can be used as a grease fill line (fill to the bottom of the line). See Figure 13.
Place the shaft with bearings into the base, carefully guiding the seals into the seal grooves. Be certain that the bearings’ outer rings sit squarely in the housing bearing seats. Bolt the “held” housing securely in place (see step 8). The “free” bearing hous- ing will be located and bolted to its mount- ing surface after the “free” bearing is prop- erly positioning in the “free” housing to ensure correct float. Note: If shimming is required, shims must cover the full mount- ing surface of the base.
Table 9
Dia. tol. for adapter & cylindrical bore mounted shaft extensions
Nominal dia. Dia. tolerance limits inches inches
over including S-1 S-2 & S-3
1 2 0.000 0.000 –0.003 –0.003 2 4 0.000 0.000 –0.004 –0.003 4 6 0.000 0.000 –0.005 –0.003 6 10 0.000 0.000 –0.006 –0.004 10 15 0.000 0.000 –0.006 –0.005 15 — 0.000 0.000 –0.006 –0.006
Step 8
Stabilizing ringsA stabilizing ring should be used if a spheri- cal roller or self-aligning ball bearing is to be “Held” or Fixed” (i.e. locating the shaft). The stabilizing ring should also be used for all toroidal roller bearing (CARB) units. In cases when only one locating ring is used, move the shaft axially so that the stabilizing ring can be inserted between the bearing outer ring and housing shoulder on the
locknut side of bearing, where practical. For bearings that will be free to float in the housing, generally center the bearings in the housing seat.
Table 10
Initial grease charge for SAF pillow block assemblies
SAF SAF SAF SAF SAF Initial charge
oz. lbs. — — 507 — — 21⁄ 2 — — 509 — — 3 — — 510 — — 4 — 308 — — — 41⁄ 2 — 309 — 609 — 5 — — 511 — — 5 — 310 — 610 — 61⁄ 2 — — 513 — — 71⁄ 2 — 311 — 611 — 8 — — 515 — — 9 — 312 — — — 10 216 313 516 613 — 13 217 — 517 — — 13 — 314 — — — 14 218 315 518 615 — 14 — 316 — 616 — 16 — 317 — 617 — 20 220 — 520 — 024 21 — 318 — 618 — 22 222 — 522 — 026 28 224 320 524 620 028 40 226 322 526 622 030 31⁄ 4 — — — — 032 31⁄ 4 228 — 528 — 034 31⁄ 4 230 324 530 624 — 33⁄ 4 232 326 532 626 036 41⁄ 4 — — — — 038 41⁄ 4 234 328 534 628 040 51⁄ 4 236 330 536 630 — 6 238 332 538 632 044 71⁄ 4 240 334 540 634 048 81⁄ 2 244 338 544 638 052 11⁄2 — 340 — 640 056 15⁄2 Figure 13
Grease fill line
Note: There must be only one “held” bear- ing per shaft. One bearing should be “free” to permit shaft expansion. Some housings require two stabilizing rings, which must be inserted to obtain a “held” assembly with the bearing centered in the housing. Stabi- lizing rings enclosed in standard housings are intended for spherical roller bearings or CARB. A different stabilizing ring is required for self-aligning ball bearings (purchased separately).
Step 9
Upper half housing (Cap)
The bearing seat in the cap should be thor- oughly cleaned, lightly oiled and placed over the bearing. With oil lubrication, use a seal- ing compound such as Permatex 2 or equiv- alent at the split surfaces; apply sparingly. Wipe a thin film near the outer edges. Excessive amounts may get forced between the housing bore and bearing outside diam- eter. This can pinch an outer ring or make a “free” bearing actually “held”.
Two dowel pins will align the cap to its mating base. Note: Caps and bases of hous- ings are not interchangeable. Each cap and base must be assembled with its original mating part. All SKF SAF and SAFS split housings are match marked with serialized identification on the cap and base to assist in assembling of mating parts. To complete the assembly, the lockwashers and cap bolts are then applied and tightened to the proper tightening torque for the specific cap bolts. See Table 11 and Figure 14. The rubber plug and plastic fitting in the cap holes of M5 style SAF housings should be removed and discarded. Replace with appropriate metallic plugs/fittings that are supplied with each SKF M5 style SAF housing.
Figure 14
SKF 'A' style SAF (iron) SKF SAFS (steel) SAE J429 grade 8 cap bolts are black in color
(use table 11 values)
8.8
SKF 'M5' style SAF (iron) ISO R898 class 8.8 cap bolts are painted blue
(use table 11 values) Identification of cap bolt grade
Table 11
Cap bolt tightening torque for SAF style housings
Size Tightening torque (ft-lbs)
(F)SAF F(SAF) SAFS
“A” style “M5” style “N”, “L” style
024 380 — — 026 380 — — 028 900 — — 030 900 — — 032 900 — — 034 900 — — 044 600 — — 048 600 — — 052 900 — — 056 870 — — 213 60 110 — 215 60 110 110(L) 216 220 110 220(L) 217 220 110 220(L) 218 220 110 110(N) 220 380 150 220(N) 222 380 150 220(N) 224 900 295 220 226 900 295 380(N) 228 900 295 600(N) 230 380 — 600(N) 232 380 — 600(N) 234 380 — 900(N) 236 380 — 2380(L) 238 600 — 1280(N) 240 600 — 1820(N) 244 900 — 2380(N) 308 110 — — 309 110 — — 310 110 — — 311 110 — — 312 110 — — 313 220 — — 314 220 — — 315 220 — — 316 380 — — 317 380 — — 318 380 — — 320 900 — — 322 900 — — 324 380 — — 326 380 — — 328 380 — — 330 380 — — 332 600 — — 334 600 — — 338 900 — — 340 870 — — Table 11
Cap bolt tightening torque for SAF style housings
Size Tightening torque (ft-lbs)
(F)SAF F(SAF) SAFS
“A” style “M5” style “N”, “L” style
509 70 45 — 510 70 45 — 511 110 60 — 513 110 60 — 515 110 60 110(L) 516 220 110 220(L) 517 220 110 220(L) 518 220 110 110(N) 520 380 150 220(N) 522 380 150 220(N) 524 900 295 220 526 900 295 380(N) 528 900 295 600(N) 530 380 — 600(N) 532 380 — 600(N) 534 380 — 900(N) 536 380 — 2380(N) 538 600 — 1280(N) 540 600 — 1820(N) 544 900 — 2380(N) 609 110 — — 610 110 — — 611 110 — — 613 220 — — 615 110 — — 616 380 — — 617 380 — — 618 380 — — 620 900 — — 622 900 — — 624 380 — — 626 380 — — 628 380 — — 630 380 — — 632 600 — — 634 600 — — 638 900 — — 640 870 — — Table 12
SKF seal alignment capabilities
Designation Description Allowable misalignment
(degrees)1)
LER Labyrinth seal (SAF 507-513) 0.3
B-9784 Contact seal (SAF 507-513) 0.1 2)
LOR PosiTrac labyrinth seal 0.3
LOR + B 10724-xx PosiTrac Plus seal 0.3
TER Taconite seal w/contact seal 0.1 2)
TER-xx V Taconite seal w/ V-ring 0.5
1) Values are approximate to cover a family of parts. For specific sizes, consult SKF application engineering 2) Optimum contact seal performance is obtained when shaft misalignment and run-out are kept to a minimum
Misalignment
The misalignment capability of SKF split housings is dependent upon the specific seal that is being used. Even though the bearing inside the housing can accommodate more misalignment, the limiting component is the seal. Refer to the table below for misalign- ment capability of specific SKF seals.
Lubrication
See Lubrication section, page 87. Should bearing temperature be below 32° F (0° C) or above 200° F (93° C), consult SKF for lubrication recommendations.