Industrial seal self study guide - SKF.com

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Testing for the Presence of Machine Lead Testing the shaft surface for machine lead can be done simply and with a minimum of tools. The most effective method requires a 36 inch (914.4mm) length of cotton quilting thread, a one ounce weight and silicone oil. Mount the shaft in a chuck so the shaft surface is level. Lightly coat the shaft with oil. Suspend the weight on the thread as shown here. Rotate the shaft at approximately 60 rpm. If the thread moves along the shaft, machine lead is present (fig. 7g). Bore Requirements The lead corner, or entering edge, of the bore should be chamfered with a 15/30 degree angle and free of burrs. The inside corner of the bore should have a maximum radius of .031 (.79mm). This will help prevent seal damage during installation. Chamfer length should be .060” to .090” (1.50 to 2.29mm); see fig. 7h. Bore Tolerance Similar to shafts, the inch (RMA) system for seal bores also uses a “floating” range based on the nominal diameter plus or minus some value depending on the base size. With the metric (ISO) standard however, the tolerances for bores (typically ISO H8) are applied as a plus value/minus zero. Unlike shafts and seal lips, the bore fit for seals can be significantly affected by the tolerance applied to the hardware. For the best results, the correct bore diameter for the tolerance system used should always be observed. Refer to the SKF Handbook of Seals for tolerance data and further information on housing bores. Bore Hardness No specific Rockwell hardness is recommended. Bore hardness need only be high enough to maintain interference with the seal’s outside diameter. Bore Material Ferrous and other commonly used metallic materials (like aluminum) are acceptable for the bore. Bore material must be compatible with the seal type used; if an aluminum bore is used, thermal expansion may have to be considered. Testing the shaft surface for machine lead is a simple process requiring a minimum of tools (fig. 7g). (fig. 7h) FINISH 100 microinch OR LESS Ra (2.5 micrometer) R .031 (0.79 mm) .060 - .090 (1.52 - 2.229 mm) 15-30 7 63
Shaft and Bore Conditions (cont.) Bore Finish A bore finish of approximately 100 micro inch Ra (2.54 μm) or smoother (100 to 200 micro inch Ra [2.54μm to 5.08μm] for aluminum), should be maintained to avoid leakage between the seal outer diameter and housing. An inside corner that is too rounded or a corner with too large a radius can cause the seal to distort when pressed into the bore. SKF applies a coating of Bore-tite to the O.D. on selected metal-clad seals on production quantities at the factory. Seals without Bore-tite can be improved by applying a non-hardening, pliable sealant to the O.D. prior to installation. 64
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Industrial seal self study guide Ma
Page 3 and 4:
CHAPTER 1— INTRODUCTION This book
Page 5 and 6:
INTRODUCTION (cont.) The Total Bear
Page 7 and 8:
BASIC SEAL TYPES (cont.) A As a sha
Page 9 and 10:
BASIC SEAL TYPES (cont.) As was ear
Page 11 and 12:
CHAPTER 2 REVIEW To take this test,
Page 13 and 14: HM14 SKF’s non-spring loaded desi
Page 15 and 16: SEAL DESIGN GROUPS (cont.) Hydrodyn
Page 17 and 18: SEAL DESIGN GROUPS (cont.) CRWA5, C
Page 19 and 20: SEAL DESIGN GROUPS (cont.) HDSB HDS
Page 21 and 22: SEAL DESIGN GROUPS (cont.) All HS s
Page 23 and 24: SEAL DESIGN GROUPS (cont.) HSF SBF
Page 25 and 26: SEAL DESIGN GROUPS (cont.) VR2 VR2
Page 27 and 28: SEAL DESIGN GROUPS (cont.) Scotseal
Page 29 and 30: SEAL DESIGN GROUPS (cont.) “OLD
Page 31 and 32: CHAPTER 3 REVIEW (cont.) 30 7. The
Page 33 and 34: V-Ring excludes contaminants, preve
Page 35 and 36: Seal Applications (cont.) An effect
Page 37 and 38: Seal Applications (cont.) Identific
Page 39 and 40: Seal Applications (cont.) Substitut
Page 41 and 42: Seal Applications (cont.) + Handles
Page 43 and 44: Seal Applications (cont.) °C °F 2
Page 45 and 46: Chapter 4 Review To take this test,
Page 47 and 48: Chapter 5—Seal Selection The firs
Page 49 and 50: Seal Selection (cont.) l A B Seal S
Page 51 and 52: Seal Selection (cont.) A longer lip
Page 53 and 54: Chapter 5 Review (cont.) 7. Substit
Page 55 and 56: Wear Sleeves (cont.) Speedi-Sleeve
Page 57 and 58: Wear Sleeves (cont.) 8. Drop the Sp
Page 61 and 62: fig. 7A Shaft surfaces must be smoo
Page 63: Shaft and Bore Conditions (cont.) S
Page 67 and 68: Chapter 7 Review (cont.) 6. Spiral
Page 69 and 70: Installation (cont.) For best resul
Page 71 and 72: Installation (cont.) 8. Check seal
Page 73 and 74: Installation (cont.) Corrective Act
Page 75 and 76: Installation (cont.) Split Seal Con
Page 79 and 80: Chapter 9—Troubleshooting Prelimi
Page 81 and 82: Troubleshooting (cont...) Causes Su
Page 83 and 84: Troubleshooting (cont...) Out-of-Ro
Page 85 and 86: Troubleshooting (cont...) Pressure
Page 87 and 88: Chapter 9 Review (cont...) 8. Garte
Page 89 and 90: Glossary of Seal Terms (cont...) Di
Page 91 and 92: Glossary of Seal Terms (cont...) MP
Page 93 and 94: Glossary of Seal Terms (cont...) Sh
Page 95 and 96: Final Exam Congratulations. You hav
Page 97 and 98: 12. A cocked seal can cause a seal
Page 99 and 100: 26. In _________________ installati
Page 101 and 102: 40. A sealing lip that is cut, turn
Page 103 and 104: 54. If a shaft is lightly grooved b
Page 105 and 106: 73. More bearings fail from the ent
Page 107 and 108: 96. Ferrous and other commonly used
Page 109 and 110: Fold Here Fold Here PLACE STAMP HER
Page 111 and 112: 110 NOTES
Page 113 and 114: 112 NOTES
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