Are You Bolt-Bound or Base-Bound?

June 25, 2012

Being bolt-bound means you have to move the machine sideways to get it aligned and you can’t: you’ve run out of room. The anchor bolt is up against the side of the hole in the foot.

Being base-bound means you need to bring the machine down to get it aligned, but you can’t: the machine feet are down against the base and there are no more shims left to remove from under them.

Are you in a quandary with either of these situations? No problem! You have five possible solutions:
* Open up the holes in the feet.
* Turn down the anchor bolts.
* Redrill and tap new holes in the base.
* Make an “Optimal Move”.
* Make a “rolling move”.

Let’s take the last one first. Making a rolling move of a bolt-bound machine simply means shimming up one side of the machine but not the other (or lowering one side but not the other.) This displaces the horizontal centerline of rotation of the shaft. But this is a big no-no! Do not do this! It will create angled soft feet and distort the machine frame when you tighten them because the feet are no longer evenly supported. Moreover, with gearboxes you may change the gear mesh pattern and destroy the machine. Many machines must be carefully leveled in addition to being aligned, so rolling moves are out!

Download entire article including making an “Optimal Move”.

Tip provided by LUDECA, Inc.
Alignment | Vibration | Balancing