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Advice on aligning shaft using flex coupler & pillow blocks

challenger

Stainless
Joined
Mar 6, 2003
Location
Hampstead, NC-S.E. Coast
I have to put a pulley on a gear pump I am using that has a 5/8" shaft. I need to use a pair of pillow blocks and a flexible coupling. I will be getting the coupling in the next day or two. It is a typical 2-hub/1-spider coupling. I have a pair of cast iron pillow blocks that have a 3/4" bore so I machined the shaft that was with the blocks so one end is .0625" for the coupling. The shaft & machined end within .003. I am looking for advice on how to best mount the pillow blocks so they align the two shafts properly. I understand the flex coupling will allow for some misalignment but I also know this pump, being it has no bearings, can wear quickly so I'd like to get the alignment as close as practical.
I had the idea to make a solid collar to connect the two shafts thinking this would put me right on but it didn't. The collar I machined within a few thousandths and the machined end of the 3/4 shaft I turned to fit this collar with a friction fit but the shaft on the pump is smaller than my collar just enough that I get a little wobble on the shaft end as I turn it by hand.
I have the specs for the dimension of the pump shaft to the pump mount but I don't have this measurement for the pillow blocks. I can easily put on on a flat surface & use this offset for the height I'll need to raise these blocks so I am left with a technique to properly align the blocks/shaft axially to the pump shaft.
Any tips are greatly appreciated.
Thanks
Howard
 
First of all your coupling is very forgiving, so dont over think it, get it within .005 and it will run forever, solid couplings in days of old were challenging, but it was millwright 101.

Scribe a straight line on your baseplate parallel to the shaft, off to the side. Clamp a good straight edge along your layout line, use the edge as a point of reference for backing up dial indicator with a block mount, mount your highest component first, check the shaft to make sure you are parallel to your layout edge, mark holes and mount. Check the bottom (or top) of the shaft and shim as needed to bring it parallel to the baseplate.

Repeat the same for the second component.

Thats the way I was taught by an old timer, we got pretty fast at doing it that way.

Edit, we use a piece of machined CRS as a indicator mount and just slide it gently along the straight edge, a mag base isnt really needed.
 
First of all your coupling is very forgiving, so dont over think it, get it within .005 and it will run forever, solid couplings in days of old were challenging, but it was millwright 101.

How close would a solid coupling have to be for me to safely run this for a short period? I'd like to test this system and I won't get my flex coupling until next week.

Scribe a straight line on your baseplate parallel to the shaft, off to the side. Clamp a good straight edge along your layout line, use the edge as a point of reference for backing up dial indicator with a block mount, mount your highest component first, check the shaft to make sure you are parallel to your layout edge, mark holes and mount. Check the bottom (or top) of the shaft and shim as needed to bring it parallel to the baseplate.[\quote]

Ok-as is normal I am a little unclear. Currently my pump shaft, which I already have bolted to my base plate, is 3-9/16" above the base plate to center. Am I using this shaft to make the recurrence line on the base? To transfer the shaft line to my base, IF my assumption above is accurate, do I just place a square on the base and touch the blade of the square to the shaft side & mark where the square is on the base? My base is plywood until I get a proven design at which point I will fabricate an aluminum base. This being the case I am dealing with wood grain/pencil width and such which will make impossible to scribe an accurate line. I can easily place a suitable material on the base for scribing & locating the shaft line to the base IF I am still following you.
I am totally lost when you say, "back up your dial indicator with block mount"
So sorry. I am not so much over thinking as I am trying to include all the variables I can think of for something I am totally unfamiliar with.
The pillow blocks have elongated mounting holes on each side to allow for some side to side mounting adjustments if this is of any help as it relates to your method?

I'd rather not assume anything about your method before I proceed. I'm not too proud to say I don't know and I'd rather wait and fully understand.

Repeat the same for the second component.

Thats the way I was taught by an old timer, we got pretty fast at doing it that way.

Edit, we use a piece of machined CRS as a indicator mount and just slide it gently along the straight edge, a mag base isnt really needed.
 
For a short run, I'd suggest removing the pillow block nearest the pump and fix the coupling to the pump shaft. Misalignment of the shaft (it sounds like it is due to questionable machining accuracy) might then be permissible for a few minutes at the pump end without undue side loads on the pump bushings. However, if the far end of your jack shaft is sweeping a big circle, then all bets are off. Start over, and turn a new jackshaft with a concentric end on it. And no 'few thou' clearance on anything that you want aligned.
 
Your pump is already mounted, so you will have to clamp your straight edge complety parellel to that, use squares and measure to get as close as you can, then loosen the pump bolts and tap it around for the last few thou, you may have to reclamp your straight edge a few times to get it right.

When I say a block mount DI, it is a shop made block of steel machined square with a dial indicator arm and holder (no magnet) this allows you to traverse down the length of the straight edge and "follow" the shaft to check for parallelisim, set your DI to read the side of the shaft first, then set for the top of the shaft to check "tilt" Also make sure the base plate is nice and flat, no burrs, twists, welds or protrusions. Typically pump mounting plates are a chunk of heavy inverted channel, I give them a quick stoning to knock off the high spots before getting started.

As for a temporary test run (solid coupling), hook it up and shim the pillow blocks with washers, let your coupling be your guide. You should be able to run it for a few minutes without any pump damage.

EDIT: Just re-read your post. Wood base plate? :eek:
 
For a short run, I'd suggest removing the pillow block nearest the pump and fix the coupling to the pump shaft. Misalignment of the shaft (it sounds like it is due to questionable machining accuracy) might then be permissible for a few minutes at the pump end without undue side loads on the pump bushings. However, if the far end of your jack shaft is sweeping a big circle, then all bets are off. Start over, and turn a new jackshaft with a concentric end on it. And no 'few thou' clearance on anything that you want aligned.

Hey wait a minute-questionable machining? Pretty bold of you to flatulate in my general direction this way. I call this a classic case of, "internet muscles" (as opposed to "beer muscles" of course). I say this all in jest needless to say.
This is my first attempt at making my own pillow block set up so I've learned a few things. I would have done the shaft end I machined down to a much higher tolerance had I known the result would have been so poor. No one likes a "wobbly shaft" .
I am just going to wait to get the flex coupling. It took me two hours to decide on, "machine, test fit X 4 times" the material to use for spacers under the pillow blocks. I didn't have much available so I used 1 1/2" PVC blocks & "machined" them on my shaper. Now I have to drill these out for mounting to the base plus decide how I want to mount the blocks on these spacers. I figure 7-12 business days for that complex operation so I'll have my flex coupling by then.
Thank you for your input.

Your pump is already mounted, so you will have to clamp your straight edge complety parellel to that, use squares and measure to get as close as you can, then loosen the pump bolts and tap it around for the last few thou, you may have to reclamp your straight edge a few times to get it right.

When I say a block mount DI, it is a shop made block of steel machined square with a dial indicator arm and holder (no magnet) this allows you to traverse down the length of the straight edge and "follow" the shaft to check for parallelisim, set your DI to read the side of the shaft first, then set for the top of the shaft to check "tilt" Also make sure the base plate is nice and flat, no burrs, twists, welds or protrusions. Typically pump mounting plates are a chunk of heavy inverted channel, I give them a quick stoning to knock off the high spots before getting started.

As for a temporary test run (solid coupling), hook it up and shim the pillow blocks with washers, let your coupling be your guide. You should be able to run it for a few minutes without any pump damage.

EDIT: Just re-read your post. Wood base plate? :eek:

Wow! I am getting tbe hammer about this little project! BTW-Hammer is my most used tool & getting hammered was my favorite pastime many years ago so maybe it's not so bad :)
Your method is now clear in my head. Thanks for the extra description. I have a few of these bases for an indicator so that's good & I'll employ your method for alignment.
Yes-a wood base. This entire project is a prototype & I am taking things on the cheap to used if it works out. If it does I will bend up some aluminum for a base & transfer the mounting holes for the motor & pump from the plywood, which is starting to look swiss chessish, to a, "real & proper" base.
If I've not mentioned my intention I am trying to setup a,"spray tank" for filling honey bee frames with liquid sucrose & this whole pump set up has been a real challenge. Thanks to many here I think I am making good progress.
Thank You
Howard
 
BTW, a short length of rubber heater hose that fights tightly over both shafts and a couple of hose clamps makes a dandy coupler in a pinch.
 
I was taught a quick way to align flexible couplings by an old millwright. Here is the method, and I've used it many times since:

1. Using a straightedge, assuming the coupling halves are the same outer diameter, line them up with the straightedge accross the coupling hubs at 12:00 & 3:00 & 9:00. You will need to decide which end of things is the "fixed end" and which end can be moved into alignment. SOmetimes, something like a pump which is coupled to piping is the fixed end, and the motor gets moved into alignment.

2. I use a piece of brass and a hammer to bump the mounting feet to get things into straightedge alignment. You should get the side-to-side ( 3:00 & 9:00) OK, and be able to measure how much you need to shim under the lower side's mounting feet to get things into rough alignment.

3. Once you have rough shimmed, check the faces of the coupling halves for parallel. I use a wedge or taper gauge with a light film of Prussian blue. Where the blue rubs off, that is where the coupling halves contact the taper gauge. I then see how the coupling faces are for parallel and move things accordingly.

4. When you have completed rough alignment with straightedge and taper gauge, it is time to put the coupling together. After you have done this, putting the center element (like the rubber "biscuit" in a "Lovejoy" type coupling) in place, you use a dial indicator. I braze a nut or a bushing tapped to take a post for a dial indicator to a common hose clamp. Different coupling hub sizes, use the appropriate hose clamp. The indicator post sticks out radially from the hose clamp, perpendicular to the shafting. clamp a dial indicator to the post so it spans the coupling and contacts the opposing coupling hub. The indicator support forms an "inverted L" so that one leg of the L is parallel to the shafting and bridges the center element of the coupling. Clamp a dial indicator to this bracket so the contact point of the indicator touches the opposite coupling hub. Position the indicator so it is at about half travel and clamp it. Bring the indicator to 12:00 and zero it.

5. Revolve the coupled shafting 90 degrees and read the indicator. Note the reading and move another 90 degrees to 6:00. You may need a mirror to read the indicator in this position. I use a mechanic's inspection mirror for this. Roll the shafting another 90 degrees and note the reading, then return to 12:00 and be sure the indicator returns to zero. If it doesn't, chances are your setup has some looseness or slop, so find it and fix it. I use just a hose clamp with a brazed on tapped lug, and whatever posts and clamps are in my dial indicator's kit.

As you revolve the shafting, the coupling halves will "work" or move in relation to each other if there is misalignment. You make a sketch, and write the readings. Sum the opposing readings ( such as +0.002"/ -0.003" at 3:00 & 9:00). This gives you a total of 0.005", and you can need to move HALF that amount for alignment. Looking at the sign ( + or -) on each reading, you see that you need to move the + side "in". You can do this with a piece of brass or hardwood and a hammer and very light tapping. Once you have this correction, reset your indicator and take another set of readings. I try to bring in the 3:00-9:00 readings first, then go after the shimming for 12:00/6:00.

6. Shims can be cut from sheet metal, or shim stock, but use as few as possible. If you use numerous thin shims to get the first alignment, it is good practice to reshim with thicker shims to avoid a "leaf spring effect". Any time you change shims, pull the bolts down hard before checking alignment with the dial indicator.

7. Once you have alignment made, you can really pull the bolts down or torque according to bolt size/grade, assuming a steel mounting and cast iron pillow blocks. Some millwrights drill and ream the feet of mounted machinery for dowel pins. The dowel pins insure the alignment will not be lost.

8. Another trick to both facilitate alignment and hold alignment in service is to make "jacking dogs". These are steel lugs, tapped for jacking screws. The steel lugs may be bolted to the bedplate or welded to the bedplate. The jack screws are often made from all thread rod, and push against the feet of the pillow blocks or motor or gearbox, pump, etc. The jack screws allow minute adjustments to be made to "dial in" an alignment, and are check-nutted off to hold the alignment in service.

The single dial indicator used accross a flexible coupling is an old trick. It is essentially used as a strain gauge. It is a very accurate way to align flex couplings. A flex coupling has some forgiveness for misalignment, but it is not a license to put machinery with shafts misaligned into service. A misalignment, while tolerated by the flex coupling, puts a sideload into the bearings and seals of pumps or motors. Shorter seal life and shorter coupling life result. SOmetimes, vibration results from this misalignment. It is a good idea to start off with the best alignment job you can do. Another thing to check for is the rigidity of the actual mounting. Some engines, motors, pumps, etc are mounted on fabricated bedplates that are too "twisty", or are pulled down on a floor that is not flat. I always start any alignment job by checking what the components are mounted on.

Incidentally, in February of 1987, I sustained a broken wrist which was set and casted. We had a number of high pressure IMO rotary screw oil pumps driven by electric motors on a job I was on. There were no millwrights, only linemen. The pumps were coupled with Lovejoy couplings. No alignment had been done or checked. The pumps were put into service, handling insulating oil in a series of "pipe type cables" that crossed under a river. In short order, the pump seals were leaking and pump shaft bearings were howling. The pumps were also eating Lovejoy coupling elements. The contractor's response was to put in a heavier duty Lovejoy coupling "spider" (different composition material). This did not fix the problem, and things continued to get worse. I was an engineer on the job, and being a mechanical engineer, got asked to take a look. It was pretty obvious that the frames these pumps and motors were mounted on were lightly built and then bolted to a concrete floor and pulled down hard. If there ever was an alignment done at the factory, it was lost when the units were mounted on the concrete floor. I said the motors needed to be aligned to the pumps, since the pumps had steel piping connecting them to all sorts of system components. This got blank looks. I said we needed millwrights, and was told this was a lineman's job, and no millwrights would be on site. I said I'd bring my own tools and align the motors. I filled a 5 gallon pail with my 6" machinist rule, combination square, wedge gauge, Prussian Blue, scriber, micrometer, dial indicator, hoseclamp/lug, snips, shim stock, hammer, brass bar, small pinch bar, and mirror. I had the pumps removed and taken to a service shop off site. There, we had new mechanical seals and bearings installed. When the pumps came back, I had the linemen remount them and reconnect the piping. I then did the alignments with one arm in a cast. Linemen took turns being my other arm, and I took everyone thru the basic steps in alignment. It became a joke that I could align pumps with one arm in a cast. The pumps ran smoothly and quietly for years afterwards, no problems. The concept of using a single indicator to span a coupling is a bit strange when you first hear of it, and doing an alignment with the coupling assembled rather than the more traditional method of indicating one coupling to the other is a bit hard to grasp. But, when you see it happen, you realize it is a strain gauge. The new laser shaft alignment systems use a similar approach, relying on spanning the coupled shafts with a laser beam and target and rotating the coupled shafts. The laser beam does the same thing the single dial indicator does.

As a safety precaution, do not work on any alignment unless you have protected yourself from accidental starting of the motor or engine, and have bled off any pressure trapped within pumps.
 
These methods are complicated but, once I can fully understand them, seem like very accurate.
I'll have to re-read your post to fully understand them but I think I get the big picture & will break down the steps.
I won't be breaking my wrist to test this technique though.
Thanks
Howard
 
Joe, thanks for taking the time to describe your alignment method. I've been reading this post with interest as I've been having a time with coupling problems myself on my loader (the hydraulic pump). Changed it over to a Lovejoy coupling and soon learned that flex coupling aren't really designed to flex very much at all. I broke a weld and squeezed out a spider in the process of learning this. I see a careful alignment in my future.
 
The way I was taught to align shafts is with a dial indicator, attach an indicator to one shaft and rotate it around the other shaft and adjust for zero change, move the indicator to the other shaft and do the same thing. It's faster in you can mount 2 indicators a few inches apart and adjust so both read zero TIR then change the indicator to the other shaft. This was done at a Major Oil Refinery for all couplings of which they had thousands. This included connecting steam turbine to gear reducer then reducer to pump. 1 HP to 10,000 HP or more. Their requirement to alignment was .0025 TIR. Coupler will last for years running 24/7.
Frank
 
Hi again guys, the trouble I have with the "spinning dial indicator method" is as follows, flipping a DI holder (no matter how rigid) from zero degrees to one eighty degrees always involves holder arm "droop" as can be seen in the bottom photos, try it for yourself, mount an indicator on a shaft and measure to the shaft itself in the 12 and 6 o-clock positions (spinning the shaft, not moving the DI), the rig pictured showed about .0065 deflection from top to bottom. I guess you could add correction factors to your math, but who wants to do that?




20130201_075926.jpg
20130201_080013.jpg
 
sag correction

Hi again guys, the trouble I have with the "spinning dial indicator method" is as follows, flipping a DI holder (no matter how rigid) from zero degrees to one eighty degrees always involves holder arm "droop" as can be seen in the bottom photos, try it for yourself, mount an indicator on a shaft and measure to the shaft itself in the 12 and 6 o-clock positions (spinning the shaft, not moving the DI), the rig pictured showed about .0065 deflection from top to bottom. I guess you could add correction factors to your math, but who wants to do that?




View attachment 68685
View attachment 68686

dial indicator sag correction factor is always used for dial indicating coupling alignment. there are 2 main types of coupling alignment

1) rim and face
2) reverse indicator
.
reverse indicator is more accurate as axial float or shaft movement in shaft axis direction can distort readings when doing rim and face.
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after you determine sag amount which is lower if you use a smaller and less heavy dial indicators and bigger diameter connecting rods often are hollow precision ground tubing, they you can measure distances between the 2 dial indicators and distances from indicators to bearing / motor hold down bolts to calculate usually using graph paper the required alignment correction moves.
.
also heat rise needs to be factored in. calculating heat rise can be done but the reliable method is to run the machine until it gets up to operating temperature and then check coupling alignment quickly and correct the heat rise misalignment so when machine is running coupling is in alignment.
.
another factor that can be even harder to predict is force from piping, motors, etc pushing and bending mounting brackets. often this is done with dial indicators on non moving parts but equipment vibration can make it hard to get a good reading. i have seen pumps with no piping attached bend so badly when pipes were connected that a perfect alignment goes out of tolerance 10x the recommended amount.
 
Froneck:

You are correct in describing what we sometimes call the "double indicator method" of shaft alignment. On larger machinery or where there are rigid flanged couplings, the method you describe is the only way. The "single indicator method" is used on flexible couplings with a fairly short span accross them, such as Lovejoy couplings. As I wrote, it is a "strain gauge" method. This strain gauge method works fine on smaller couplings with a resilient element. On something like a gear tooth coupling or roller chain coupling, I use the double indicator method you have described.

On smaller couplings with a good solid mounting for the indicator, indicator "droop" is not an issue. On larger couplings, where the indicator bracket has to span a longer distance, indicator droop is a real issue. We usually fabricate the indicator brackets for the large coupling alignments using pipe and some trussing to create a light but rigid bracket with very minimal deflection. We secure this type bracket to the shafting or coupling hub using clamps made from roller (sprocket) chain, vee blocks and chain tensioners that can use a screw- very similar to a pipefitter's chain vise.

Alignment of larger pumps in powerplants was often a headache due to pipe strain transmitted into the pumps. Some of these pumps, such as boiler feedwater pumps, had the pipe connections welded to the pump suction and discharge connections. This pretty much locked the pump into location. If the pump were driven by a steam turbine, then there was a driver that was also tied to piping. It made for difficult alignments. I work in a hydroelectric plant, so we do not have steam or hot/high pressure steam or feedwater to deal with. On cold water service pumps, I use isolation joints between the pumps and the piping. These are flanged end "accordion" bellows type joints made of synthetic rubber. Guide rods are used, so the joint is always held in line. We fit things so the bellows joints go into the piping in their "neutral" length.

As they say: "ignorance is bliss". I recall when I arrived at this powerplant in 1989, a lot of stuff went on that was not really "engineered". A lot of seat of the pants stuff. One problem was that these big air handler blower shafts kept chewing up their bearings and breaking in service. The air handlers were driven with multiple vee belts, so shaft alignment really was not an issue. The shafting passed through several carrier bearings and had 3 or 4 blower runners on it. I happened to be in the plant machine shop one day, and noticed a mechanic chucking a piece of cold rolled in a 3 jaw chuck on the 25" engine lathe. He was getting set to turn a reduced diameter on it. I asked him what it was for, and he told me it was another air handler shaft, and remarked that these shafts kept breaking in service. He also remarked about high vibration in the air handler blowers, to the effect that they were shaking themselves apart. He told me the turned down portion where the drive pulley went on.

I asked the mechanic why he was chucking the shaft material in a 3 jaw chuck and not indicating it in a four jaw chuck. The mechanic said this was news to him and it was how everyone made those shafts. I got hold of the supervisor and told him he was creating an eccentric condition, runout in the pulley would put vibration and bending fatigue into the shaft. I got told to mind my own business. Another few shafts went bust and bearings got chewed up, and I got asked to look into it. I made a few changes. One was to use 1141 Stressproof shafting steel, turned, ground & polished. The other was to require the turned down portion be done using a four jaw chuck indicated so it had zero runout, and lastly, a nice radius where the turned down portion met the shoulder. That made a world of difference. Shaft and bearing failures stopped happening. That then put us on the track of doing a better alignment of the motor and fan shaft sheaves (pulleys), and vibration dropped even more.

I've learned that in mechanical alignment, there are a few areas beyond the actual shaft or coupling alignment that have to be addressed. The first is how rigid and solid the mounting is. The second is whether the machinery being mounted has a solid footing and no "soft feet". A soft foot is a mounting foot that does not have solid support from the shims or mounting surface under it. A soft foot can cause a misalignment and vibration.
Then, I check for piping strain. Ideally, the piping is properly supported and does not impose any force on the machinery (pumps, compressors) it is made up to. If these areas are not checked and set right, a static alignment can appear to be dead nuts accurate but in service, alignment is lost.

I did some alignment on generators and larger reduction gears driven by medium speed diesel engines. On those applications, I ran a calculation for thermal expansion of the engine. Cold alignment was always done so the centerline of the crankshaft was a little lower than the centerline of the generator or reduction gear. As the engine came up to temperature, the crankshaft rose up to the same centerline as the generator or gearbox. Of course, I took the operating temperature of the generator or gearbox into account as well.
 
I've all ways used the 2 indicator set up when aligning shafts, and used last word type indicators. My memorable installation was in a paper mill putting in a 5,000 GPM pump driven by a 200 HP electric motor, the mounting plate was 1 1/4" floated on a wet concrete base , told them that when it rusts the plate will move, was told to shut up and install the unit, was indicating in the pump and motor had it with in about .025" both ways, when the a**hole foreman came over and asked what I was doing told him where I was at he said weld it it's close enough I told him the specs called for less than .005, was told again to weld it then he stated (that's job security just do what your told) went back to the office and quit, 1987 money $24.65 per hour, was asked why am I quitting told the owner I didn't want to get any one in trouble and said that he understood, 2 weeks later the a**hole was gone.
 
No thermite I didn't go back, good thing because about a year later the whole place was gone. It was fun while it lasted, but if I can't do a job right I don't want to do it at all.
 
Resilient couplers should also be aligned well. LoveJoy recommends .005. Poorly aligned shafts even if only .010 will destroy a LoveJoy spider in no time.
I too use the Starrett Last word indicator, they are very sensitive and light so there is very little sag. My Uncle told me how they measured bars sag. There were times they needed to align shafts that were a few feet apart and had a spool piece to couple them. Unfortunately I forgot how but it as a very simple way. I did buy the Starrett shaft alignment kit but really didn't care for it. I like my two last word setup better. I gave my kit to my son.
The better the alignment the longer the coupler will last, bearings and seals too!
 
Ok-I received the couplings yesterday & plan on doing the alignment today once I get me lathe headstock put back together - another story but I found a problem with spindle TIR as I was checking the shaft I am using.
Given the pump setup I am prototyping is a very small size I am curious if the same degree is precision is required as described in previous posts? The total length of the shaft is 8" & I am attaching a Lovejoy 5/8"bore hub to the 5/8" pump shaft and the shaft for the pulley is 3/4" so I have two hubs with different bores but the same OD. The pillow blocks will be less than 3" apart as the distance between the Lovejoy coupling and the hub of my pulley is about 6". I don't want to butt a pillow block up against the coupling obviously & they are 1" wide so the span between the two blocks is very short.
Do I really need to be so precise with this light duty application?
The Lovejoy specs say a lot more misalignment can be present using the coupling I purchased. Are these specs just allowing them to sell more coupling?
Thanks
Howard
 
Howard,

I assume your proposed arrangement is as follows: Pump >< flex coupling >< pillow block #1 >< pillow block #2 >< pulley.
If so, your first task is to make your life easy by making the pillow blocks with pulley into a single machine. Do this by mounting both pillows onto a single baseplate (a sturdy flat plate or an H frame will do.) Then all you have to do is shim and move the entire plate with pillows to align to the pump.

Carefully lay out and mark the desired positions of your pillow blocks on the plate. Lay your solid shaft into the pillow blocks, and bolt the pillow blocks tight to your plate. If your plate or H-frame is flat and of good quality, you should not induce any soft foot (distortion in the bearings or base plate, or deflections in the shaft.) Rotate the shaft by hand and observe any tightness or wobble in the bearings if you can. It should feel completely free and easy to rotate.

Now bolt the plate with pillow blocks to the main baseplate of the pump or other foundation frame, allowing at least 50 mils of shims under each of the four support locations. Install horizontal jackscrews (pushblocks) on the main base to facilitate performing horizontal alignment adjustments of the plate. Now couple the pulley shaft to the pump shaft and use a good laser shaft alignment system (Rotalign Ultra or Optalign Smart or ShaftAlign) to check soft foot of the pillow block plate assembly with respect to the main base. Now take laser alignment readings and align the pulley shaft to the pump shaft by simply shimming and moving the plate with the pillow blocks, availing yourself of the live Move function of these laser systems, so no need to paste indicators against the side of the plate to monitor your moves. Note that you never have to shim and move the pillow blocks individually, saving yourself an awful lot of grief!

Next, install the belts on the pulley and tension them by moving the drive motor, all the while looking out for any alignment changes between the pulley shaft and the pump shaft by means of the live move monitoring function of your laser.

Finally, laser align your sheaves (pulleys) using a DotLine or SheaveMaster laser pulley alignment tool and tension the belts to the correct tension (1/64" per inch of span length for new belts) all the while monitoring the alignment with the line laser. Don't forget to recheck the alignment and retension the belts after they've run for a while.

Good luck!
 








 
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