Handbook of Shaft Alignment Part 5 doc

The removal of the coupling hub is accomplished by pulling the hub off the shaft with an acceptable puller mechanism and at times cooling the shaft with a dry ice pack. Shrink fit coupling hubs should always have fine threaded puller holes (preferably four) in the end of the coupling as shown in Figure 4.31. Bearing-type pullers that ‘‘push’’ the hub off from the backside are not recommended as there is a great possibility that the puller can twist or pitch slightly preventing a straight axial draw on the hub. For larger shaft diameters with tight interference fits, it may be necessary to apply gentle heating to the coupling for removal. 4.9.4 SPLINED SHAFT WITH END LOCK NUT OR LOCKING PLATE A splined shaft and coupling arrangement is shown in Figure 4.32. There should be a slight interference fit (0.0005 in.) to prevent backlash or rocking of the hub on the shaft. 4.9.5 TAPERED BORE—INTERFERENCE FIT WITH KEYWAYS Tapered shaft ends are generally used where high torques and speeds are experienced on rotating machinery, necessitating a tight coupling hub to shaft fit up. The shaft end is tapered to provide an easier job of removing the coupling hub. The degree of taper on a shaft end is usually expressed in terms of its slope (inches per foot). The amount of interference fit is expressed in inches per inch of shaft diameter. The general rule for interference fits for this type of shaft arrangement is 1 mil per inch of shaft diameter. The distance a coupling hub must travel axially along a shaft past the point where the hub is just touching the shaft at ambient temperatures is found in the following equation: HT ¼ 12I ST (4:2) TABLE 4.4 Guidelines for Shrink Fits on Shafts Shaft Diameter (in.) Interference Fit (in.) 1/2 to 2 2 to 6 6 and up 0.0005 to 0.0015 in. 0.005 to 0.0020 in. 0.0001 to 0.00035 inches per inch of shaft diameter A B C D Compare A to B and C to D Coupling hub Key Shaft FIGURE 4.30 Measuring the shaft and coupling hub for proper fits. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C004 Final Proof page 170 6.10.2006 5:44pm 170 Shaft Alignment Handbook, Third Edition where HT is the distance the coupling hub must travel to provide an interference fit equal I (mils), I is the interference fit (mils), and ST is shaft taper (in.=ft). The procedure for mounting a tapered coupling hub with keys: 1. Mount bracket firmly to coupling hub and slide hub onto shaft end to lightly seat the hub against the shaft. Insure all surfaces are clean. 2. Measure hub travel gap HT with feeler gauges and lock nut down against bar. Use Equation 3.2 to determine the correct axial travel needed to obtain the required inter- ference fit onto the shaft. 3. Remove the coupling hub and puller assembly and place in an oven or hot, clean oil bath to desired differential temperature. Refer to Equation 4.1 to determine the required temperature rise to expand the coupling hub. 4. Set key in keyway and insure all contact surfaces are clean and burr free. 5. Carefully slide the heated coupling hub onto the shaft until the center measurement bolt touches the shaft end and hold in place until hub has cooled sufficiently. 4.9.6 COUPLING HUB TO SHAFT SURFACE CONTACT One extremely important and often overlooked consideration when working with tapered shafts and coupling hubs is the amount of surface contact between the shaft and hub. Due to FIGURE 4.31 Coupling hub puller. FIGURE 4.32 Splined shaft end. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C004 Final Proof page 171 6.10.2006 5:44pm Flexible and Rigid Couplings 171 slight machining inaccuracies, coupling hubs may not fully contact the shaft resulting in a poor fit when the hub is shrunk or pressed on in final assembly. To check the surface contact, apply a thin coat of Prussian blue paste to the inner bore of the coupling hub with your finger or a soft cloth. Slide the coupling hub axially over the tapered shaft end until contact is made and rotate the coupling hub about 158 to transfer the paste to the shaft. Draw the coupling hub off and observe the amount of Prussian blue paste that trans- ferred from the hub to the shaft (not how much blue came off the inside bore of the coupling hub). If there is not at least 80% contact, the fit is not acceptable. If the bore discrepancies are slight, it is possible to lap the surfaces with a fine grit lapping compound. Apply the compound around the entire surface contact area of the tapered shaft end, lightly pushing the coupling hub up the taper and rotating the coupling hub alternately clockwise and counterclockwise through a458 arc. Check the surface contact after 10 or 12 lapping rotations. Continue until surface contact is acceptable. However if a ‘‘ridge’’ begins to develop on the shaft taper before good surface contact is made, start making preparations for machining of the shaft and the coupling hub. It is better to bite the bullet now than try to heat the hub and put it on only to find out that it does not go on all the way or to pick up the pieces of a split coupling hub after the unit ran for a short period of time. 4.9.7 KEYLESS TAPER BORES After working with shafts having keyways to prevent slippage of the coupling hub on the shaft, it seems very unnerving to consider attaching coupling hubs to shafts with no keys. Keyless shaft fits are quite reliable and installing hubs by hydraulic expansion methods proves to be fairly easy if installation and removal steps are carefully adhered to. As the interference fits are usually ‘‘tighter’’ than found on straight bores or tapered and keyed systems, determining a proper interference fit will be reviewed. 4.9.8 PROPER INTERFERENCE FIT FOR HYDRAULICALLY INSTALLED COUPLING HUBS The purposes of interference fits are twofold: 1. Prevent fretting corrosion that occurs from small amounts of movement between the shaft and the coupling hub during rotation. 2. Prevent the hub from slipping on the shaft when the maximum amount of torque is experienced during a start up or during high running loads. For rotating shafts, the relation between torque, horsepower, and speed can be expressed as T ¼ 63,000P n (4:3) where P is the horsepower, T is the torque (in lbs), and n is the shaft speed (rpm). The maximum amount of shearing stress in a rotating shaft occurs in the outer fibers (i.e., the fibers at the outside diameter) and is expressed as t max ¼ Tr J ¼ 16T pd 3 (4:4) where t max is the maximum shear stress (lb=in.), T is the torque (in lbs), r is the radius (in.), d is the diameter (in.), and J is the polar moment of inertia, J ¼ pr 4 =2 ¼ pd 4 =32. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C004 Final Proof page 172 6.10.2006 5:44pm 172 Shaft Alignment Handbook, Third Edition The accepted ‘‘safe allowable’’ torsional stress for the three commonly used types of carbon steel for shafting can be found in Table 4.5. Therefore the torsional holding requirement for applied torques is expressed as T ¼ t max pd 3 16 (4:5) The amount of torque needed to cause a press fit hub to slip on its shaft is given by T ¼ mppLd 2 2 (4:6) The amount of contact pressure between a shaft and a coupling hub is related to the amount of interference and the outside diameters of the shaft and the coupling hub and is expressed as p ¼ IE(DH 2 À DS 2 ) 2(DH 2 )(DS) (4:7) where p is the contact pressure (lbs=in. 2 ), I is the interference fit (mils), E is the modulus of elasticity (30Â10 6 lb=in. for carbon steel), DH is the outside diameter of coupling hub (in.), and DS is the outside diameter of shaft (in.). As the shaft is tapered, dimension DS should be taken on the largest bore diameter on the coupling hub where the contact pressure will be at its minimum value as shown in Figure 4.34. Therefore to find the proper interference fit between a coupling hub and a tapered shaft to prevent slippage from occurring: 1. Determine the maximum allowable torque value for the shaft diameter and the shaft material. 2. Determine the contact pressure needed to prevent slippage from occurring based on the maximum allowable torque value found in step 1. 3. Calculate the required interference fit (solve for p in Equation 4.6 and i in Equation 4.7). 4.9.9 INSTALLATION OF KEYLESS COUPLING HUBS USING HYDRAULIC EXPANSION Installing keyless taper hubs requires some special hydraulic expander and pusher arrange- ments to install or remove the coupling hub onto the shaft end. Figure 4.35 shows the general arrangement used to expand and push the hub onto the shaft. TABLE 4.5 Allowable Torsional Stresses for Shafts t max Allowable Torsional Stress (psi) 5000 10000 11000 1040 4140 4340 AISI # Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C004 Final Proof page 173 6.10.2006 5:44pm Flexible and Rigid Couplings 173 The procedure for installation of coupling hub using hydraulic expander and pusher assembly: 1. Check for percentage of surface contact between coupling hub and shaft (must have 80% contact or better). 2. Insure all mating surfaces are clean and that oil passageways are open and clean. 3. Install ‘‘O’’ rings and backup rings in coupling hub and shaft insuring that backup ring is on ‘‘outside’’ of ‘‘O’’ ring with respect to hydraulic oil pressure. Lightly oil the ‘‘O’’ rings with hydraulic fluid. Place coupling hub (and hub cover) onto shaft. 4. Install expander pump supply line to shaft end. Install the pusher piston assembly onto the end of the shaft insuring that the piston is drawn back as far as possible. Hook up the expander pump and begin pumping hydraulic oil through supply line to bleed any air from expansion ports and expansion groove in shaft. Once the oil has begun to seep through the coupling hub ends, lightly push the coupling hub against the shaft taper and begin to pump oil into the pusher piston assembly to seat the piston against the coupling hub. 5. Place a dial indicator against the backside of the coupling hub and zero the indicator. 6. Start applying pressure to the pusher piston assembly forcing the hub up the taper (approximately 2000 to 4000 psig). 7. Slowly increase the pressure on the expander pump supply line until the coupling hub begins to move. The hydraulic pressure on the pusher piston assembly will begin to drop off as the hub begins to move. Maintain sufficient pressure on the pusher piston to continue to drive the hub onto the shaft. If the pusher piston pressure drops off considerably when the expansion process is underway, there is a great potential for the ‘‘O’’ rings to ‘‘blow out’’ the ends of the coupling hub immediately seizing the hub to the shaft. FIGURE 4.33 Measuring tool for proper interference fits on tapered shaft ends. FIGURE 4.34 Shaft and coupling hub outside diameter measurement locations. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C004 Final Proof page 174 6.10.2006 5:44pm 174 Shaft Alignment Handbook, Third Edition 8. Continue forcing the hub up the shaft until the desired amount of hub travel and interference fit is attained. The expansion pressure will have to attain the required holding pressure as defined in Equation 4.7. 9. Once the correct hub travel has been achieved, maintain sufficient hydraulic pressure on the pusher assembly to hold the coupling hub in position and bleed off the pressure in the expansion system. Allow 15–20 min to elapse while bleeding to insure any trapped oil has had a chance to escape before lowering the pusher piston pressure. 10. Remove the pusher and expander assemblies. The removal of the coupling hub is achieved by reversing the installation process. The key to successful installation is to take your time and not try to push the hub up the shaft end all in one move. BIBLIOGRAPHY Alignment Loading of Gear Type Couplings, Bently Nevada Applications Notes no. (009)L0048, Bently Nevada Corp., Minden, Nevada, March 1978. Anderson, J.H., Turbocompressor drive couplings, J. Eng. Ind., ASME, paper no. 60-WA-212, January 1962, pp. 115–123. Baer, L., Tolerant couplings, Mech. Eng., 111(5), 58–59, 1989. Bannister, R.H., Methods for modelling flanged and curvic couplings for dynamic analysis of complex rotor constructions, J. Mech. Des, Trans. ASME, 102(1), 130–139, 1980. Beard, C.A., The selection of couplings for engine test beds, second Intl. Conf. on Vib. Rotating Mach., September 1–4, 1980, Churchill College, Cambridge, UK, C267=80, pp. 115–118. Bloch, H.P., Why properly rated gears still fail? Hydrocarbon Process., 95–97, 1974. Bloch, H.P., Less costly turbomachinery uprates through optimized coupling selection, Proc. Fourth Turbomachinery Symp., Oct. 1975, Gas Turbine Laboratories, Texas A&M University, College Station, TX, pp. 149–152. Bloch, H.P., How to uprate turboequipment by optimized coupling selection? Hydrocarbon Process., 55(1), 87–90, 1976. Bloch, H.P., Use keyless couplings for large compressor shafts, Hydrocarbon Process., 181–186, 1976. Bloch, H.P., Improve safety and reliability of pumps and drivers, Part 2—Gear coupling vs nonlubri- cated couplings, Hydrocarbon Process., 56(2), 123–125, 1977. Broersma, G. (Ed.), Couplings and Bearings, Part I Couplings, H. Stam, Culemborg, 1968, pp. 1–82. Brown, H.W., A reliable spline coupling, J. Eng. Ind., Trans. ASME, 101(4), 421–426, 1979. FIGURE 4.35 Hydraulic expander and pusher assembly. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C004 Final Proof page 175 6.10.2006 5:44pm Flexible and Rigid Couplings 175 Bu ¨ hlmann, E.T. and Luzi, A., Rotor instability due to a gear coupling connected to a bearingless sun wheel of a planetary gear, Proc. 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Fifth Turbomachinery Symp., Oct. 1976, Gas Turbine Laboratories, Texas A&M University, College Station, TX, pp. 125–131. Dewell, D.L. and Mitchell, L.D., Detection of a misaligned disk coupling using spectrum analysis, J. Vib., Acoust., Stress, Rel. Des., Trans. ASME, 106(1), 9–16, 1984. Eshleman, R.L., The role of sum and difference frequencies in rotating machinery fault diagnosis, second Intl. Conf. on Vib. Rotating Mach., Sept. 1–4, 1980, Churchill College, Cambridge, UK, C272=80, pp. 145–149. Finn, A.E., Instrumented couplings: The what, the why, and the how of the indikon hot-alignment measurement system, Proc. Ninth Turbomachinery Symp., Dec. 1980, Texas A&M University, College Station, TX, pp. 135–136. Foszcz, J.L., Couplings—they give and take, Plant Eng., 42(18), 53–57, 1988. Gensheimer, J.R., How to design flexible couplings? Mach. Des., 33(19), 154–159, 1961. Gibbons, C.B., Coupling misalignment forces, Proc. 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Kojima, H. and Nagaya, K., Nonlinear torsional vibrations of a rotating shaft system with a magnet coupling, Bull. JSME , 27(228), 1258–1263, 1984. Loosen, P. and Prause, J.J., Frictional shaft—hub connectors—analysis and applications, Design Eng., January 1974. Mancuso, J.R., Moments and forces imposed on power transmission systems due to misalignment of a crown tooth coupling, Master’s Thesis, Pennsylvania State University, Hershey, PA, June 1971. Mancuso, J.R., A New Wrinkle to Diaphragm Couplings, ASME, paper no. 77-DET-128, June 24, 1977. Mancuso, J.R., The manufacturer’s world of coupling potential unbalance, Proc. 13th Turbomachinery Symp., November 1984, Texas A&M University, College Station, TX, pp. 97–104. Mancuso, J.R., Disc vs diaphragm couplings, Mach. Des., 58(17), 95–98, 1986. Mancuso, J.R., Couplings and Joints, Marcel Dekker, New York, 1986. [ISBN #0–8247–7400–0] Marmol, R.A., et al., Spline coupling induced nonsynchronous rotor vibrations, J. Mech. Des, Trans. ASME, 102(1), 168–176, 1980. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C004 Final Proof page 176 6.10.2006 5:44pm 176 Shaft Alignment Handbook, Third Edition Maxwell, J.H., Vibration analysis pinpoints coupling problems, Hydrocarbon Process., 59(1), 95–98, 1980. McCormick, D., Finding the right flexible coupling, Des. Eng., 52(10), 61–66, 1981. Milenkovic, V., A new constant velocity coupling, J. Eng. Ind., Trans. ASME, 99(2), 367–374, 1977. Miller, F.F., Constant-velocity universal ball joints, Mech. Des., 37(9), 184–193, 1965. Oberg, E., Jones, F.D., and Horton, H.L., Machinery’s Handbook, 21st ed., Industrial Press Inc., New York, 1980. Ohlson, J.F., Coupling of misaligned shafts, US PATENT, 4187698, February 1980. Ota, H. and Kato, M., Even multiple vibrations of rotating shaft due to secondary moment of a universal joint, Third Intl. Conf. on Vib. Rotating Mach., Sept. 11–13, 1984, University of York, UK, C310=84, pp. 199–204. Pahl, G., The operating characteristics of gear-type couplings, Proc. Seventh Turbomachinery Symp., Dec. 1978, Gas Turbine Labs, Texas A&M University, College Station, TX, pp. 167–173. Patterson, C., et al., Vibration aspects of rolling mill horizontal drives with reference to recent coupling development, second Intl. Conf. on Vib. Rotating Mach., Sept. 1–4, 1980, Churchill College, Cambridge, UK, C297=80, pp. 315–320. Peeken, H., et al., A new approach to describe the mechanical performance of flexible couplings in drive systems, Proc. Intl. Conf. Rotordynamics, Sept. 14–16, 1986, Tokyo, Japan, pp. 159–163. Phillips, J. and Vowles, B., Flexible metallic couplings, Pump Compressors for Offshore Oil Gas Conf., June 29–July 1, 1976, University of Aberdeen, UK, C135=76, pp. 103–108. Potgieter, F.M., Cardan universal joints applied to steel mill drives, Iron Steel Eng., 46(3), 73–79, 1969. 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Shaw, G.V., Employing limited end play couplings saves motor bearings—sometimes, Power, 120–121, 1955. Shigley, J.E. and Mischke, C.R. (Eds.), Standard Handbook of Machine Design, McGraw-Hill, New- York, 1986, pp. 29.1–29.38, chap. 29. Spector, L.F., Flexible couplings, Mach. Des., 30(22), 102–128, 1958. Wattner, K.W., High speed coupling failure analysis, Proc. Fourth Turbomachinery Symp., Oct. 1975,Gas Turbine Labs, Texas A&M University, City Station, TX, pp. 143–148. Weatherford, W.D., Jr., et al., Mechanisms of wear in misaligned splines, J. Lub. Tech., Trans. ASME, 90(1), 42–48, 1968. Williams, R.H., Flexible coupling, US PATENT, 4203305, May 1980. Winkler, A.F., High speed rotating machinery unbalance, coupling or rotor, Proc. Mach. Vib. Monit. Ann. Mtg., Apr. 19–21, 1983, Houston, TX, pp. 75–80. Wireman, T., A fitness plan for flexible couplings, Power Transm. Des., 25(4), 20–22, 1983. Woodcock, J.S., Balancing criteria for high speed rotors with flexible couplings, Intl. Conf. Vib. Noise in Pump, Fan and Compressor Installations, Sept. 16–18, 1975, University of Southampton, UK, C112=75, pp. 107–114. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C004 Final Proof page 177 6.10.2006 5:44pm Flexible and Rigid Couplings 177 Wright, J., Which shaft coupling is best—lubricated or nonlubricated? Hydrocarbon Process., 54(4), 191–193, 1975. Wright, C.G., Tracking down the cause of coupling failure, Mach. Des., 49(14), 98–102, 1977. Zirkelback, C., Couplings—a user’s point of view, Proc. Eighth Turbomachinery Symp., Nov. 1979, Texas A&M University, College Station, TX, pp. 77–81. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C004 Final Proof page 178 6.10.2006 5:44pm 178 Shaft Alignment Handbook, Third Edition 5 Preliminary Alignment Checks In Chapter 1, we examined the eight basic steps of aligning rotating machinery. This chapter will cover in detail the tasks identified in step 4, conducting and performing any preliminary checks before starting the alignment. Perhaps the most overlooked step in the process of aligning rotating machinery is this one. All too often, people who skip this step find themselves having problems in measuring the off-line shaft positions accurately, adding and then removing shim stock several times under the machinery feet, and they frequently find themselves ‘‘chasing their tail,’’ trying to reposition the machines laterally several times with marginal or no success. After wasting several hours in their attempt to align the machinery, they realize that something is wrong and they go back to check for many of the problems discussed herein. In summary, you will be trying to find and correct any problems in the following areas: . Unstable or deteriorated foundations and base plates . Damaged or worn components on the rotating machinery (e.g., machine casings, bear- ings, shafts, seals, couplings) . Excessive runout conditions (e.g., bent shafts, improperly bored coupling hubs) . Machine casing to base plate interface problems (e.g., soft foot) . Excessive piping, ductwork, or conduit forces Some of the items mentioned above are related very closely to the information given in Chapter 3 on foundations, base plates, sole plates, and piping strain and so it is recommended that you review this chapter. As discussed in Chapter 1, a considerable amount of time can be spent on these preliminary checks and corrections. In fact, I typically spend much more time for performing these tasks it takes to actually align the machinery. Many of the problems may be time consuming, expensive, and difficult to correct. Because of this, there is a great tendency to come up with excuses for not doing it. 5.1 FOUNDATION AND BASE PLATE CHECKS With respect to the successful long-term operation of the machinery, an outstanding align- ment job can quickly deteriorate if the equipment is perched on unstable frames, inertia blocks, or foundations. Chapter 3 discussed about what desired design features should be incorporated into foundations and base plates but these features may not necessarily exist on the machinery that is worked on. Therefore the first place of looking for problems would be in the supporting structure for the machinery. A quick review of Figure 3.19 through Figure 3.25 will show examples of what to check for and correct. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C005 Final Proof page 179 26.9.2006 8:36pm 179 [...]... FIGURE 5. 28 Measuring runout on the same drive shaft near the top of the shaft FIGURE 5. 29 Measuring runout on a stub shaft Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 199 Preliminary Alignment Checks 26.9.2006 8:36pm 199 FIGURE 5. 30 Metal shaving found on mating face of stub shaft causing the runout in Figure 5. 29 made as shown in Figure 5. 29 When the stub shaft. .. and soft solder above 8 mils FIGURE 5. 5 Sliding bearing design Housing Shaft Shaft “attitude” angle Radial (aka diametral) bearing clearance should range from 3/4 to 2 mils/in of shaft diameter (e.g., a 4 in diameter shaft should have a clearance range of 0.003 to 0.008 in.) Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 184 184 26.9.2006 8:36pm Shaft Alignment Handbook, ... exist When aligning rotating machinery shafts, the centerlines of rotation of each shaft are identified and then placed in a collinear axis Ignoring the possibility of runout and very possible aligning of two bent shafts lead to a huge mistake Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 202 202 5. 5 26.9.2006 8:36pm Shaft Alignment Handbook, Third Edition MACHINE HOUSING... vertical pump shaft at two different locations along the length of the shaft There were 12þ mils of runout discovered at the measurement taken in Figure 5. 27 and 15 mils of runout discovered at the measurement taken in Figure 5. 28 with the ‘‘high spots’’ in the same angular Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 196 196 26.9.2006 8:36pm Shaft Alignment Handbook, ... its housing 4 A combination of two or more of the items above Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 182 182 26.9.2006 8:36pm Shaft Alignment Handbook, Third Edition FIGURE 5. 3 Performing a lift check on a pump shaft If the inner race is loose on the shaft, the inner race will begin ‘‘skidding’’ on the shaft, eventually damaging the shaft (if it has not already... to the end of a motor shaft The stub shaft was used to drive the main oil pump for the motor and compressor drive system An excessive amount of runout was noticed when the checks were FIGURE 5. 27 Measuring runout on a vertical drive shaft above a threaded coupling Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 198 198 26.9.2006 8:36pm Shaft Alignment Handbook, Third... FIGURE 5. 23 Measuring runout on a long drive shaft section midway between the support bearings FIGURE 5. 24 Measuring runout on the backside of the gear coupling hub attached to a steam turbine FIGURE 5. 25 Measuring runout on the backside of a gear coupling hub attached to a compressor Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 197 26.9.2006 8:36pm Preliminary Alignment. .. lower end of the upper shaft was not machined at a precise 908 angle to the centerline of the shaft When the upper shaft fully engaged into the threaded coupling, as the ends of the two shafts met, the slight angle on the lower end of the upper shaft caused the shaft to pitch sideways producing the excessive runout condition Figure 5. 29 and Figure 5. 30 show a similar problem with a stub shaft that... clearance Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 192 192 26.9.2006 8:36pm Shaft Alignment Handbook, Third Edition Stuffing box 1.118Љ 1.003Љ 1.046Љ West Pump shaft East 0.9 85 FIGURE 5. 17 Stuffing box clearance measured on pump in Figure 5. 16 more commonly used lubricant seals: lip seals and labyrinth seals Lip seals are frequently made of rubber and can easily... indicators as illustrated in Figure 5. 22 Runout checks should also be made at several points along the length of Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 1 95 26.9.2006 8:36pm 1 95 Preliminary Alignment Checks Checking shaft and coupling hub “runout” Keep the dial indicator still 01 + 0_ 01 02 02 03 03 04 05 04 Rotate this shaft through 360˚ The dial indicator . alloy) HousingLubricant Shaft Shaft “attitude” angle FIGURE 5. 5 Sliding bearing design. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 183 26.9.2006 8:36pm Preliminary Alignment. locations. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C004 Final Proof page 174 6.10.2006 5: 44pm 174 Shaft Alignment Handbook, Third Edition 8. Continue forcing the hub up the shaft until. elements FIGURE 5. 4 Rolling element bearing design. Piotrowski / Shaft Alignment Handbook, Third Edition DK4322_C0 05 Final Proof page 182 26.9.2006 8:36pm 182 Shaft Alignment Handbook, Third