The procedure for aligning two rotating machines requires measuring their relative shaft positions and adjusting one or both machines. Until recently, though, how closely the shafts need to be aligned was an open question. That changed with the publication of American National Standards Institute/Acoustical Society of America (ANSI/ASA) standard 2.75-17.

“What’s the proper clearance between a shaft and the sleeve bearing it rides in?” Chances are each of us has a rule of thumb for this, probably related to shaft diameter.