GREETINGS: I vote for the dial indicator(S)... ALSO be sure the pump base is grouted in place, the piping does not pull the pump out of allignment, and recheck after a day or two... I have been known to use TWO(2) dial indicators, one behind, the other to check for shaft paraellness ?, or 180, or 90  degreeses  apart...Sometimes a driver can be very out, and the greater the size the less room for error. Remember skilled people are fewer all the time, bases can be warped, and thermal action.....
 

In an absolute sense, I struggle to believe that lasers are "better" than dial indicators. In a practical sense, lasers get the nod.  Both will do the job very well. I believe that using dial indicators require a higher skill level. Lasers remove the issue of measuring and accounting for bracket sag, which can be considerable. Two indicators mounted to the commonly used chain clamp can easily sag 8 to 10 Chemical pump mils over a typical coupling span of 8".
 

Any mention of some compensation when aligning the machinery cold?What type/style of coupling?IMO Any alignment using the coupling features ( OD or face) must first establish the runout of those features.  I've been hurt badly assuming any feature runs "true."The bypassing of coupling hub runout is one big advantage of both reverse indicator (once indicator or bracket sag is measured and compensated for) and laser methods.
 

Your talking 0.004" deviation, big enough to drive a truck through. Dials will work quite fine.  Most people that have the alignment package will know how to use them.  They will also give you a report.  If this is a one of, lasers run about $20k to buy, dials < $1k.  Wow, this thread is kind of like the slide rule thread in another forum.  When I learned how to align with dial indicators I still carried a slide rule in my pocket.  Nothing wrong with laser but it is overkill for this application.  Use the two indicator method recommended above.

2011-09-02

Back