If the base plate has jackbolts installed, the task of moving the machine is made much easier. In many situations, it is best to have jack screws installed at the time of the alignment rather than trying to move the machine some other way, which is often more difficult and requires more time.
Before any of the hold-down bolts are loosened, all of the jackbolts must be loosened on the machine. Any unequal pressure of the jackbolts could result in an uncontrolled move and require the technician to take another set of alignment readings. When loosening the hold-down bolts, back them off just enough to allow the machine to slide sideways. Since it takes very little pressure on the jackbolt to move the machine horizontally, there is no real need to completely back off or remove the hold-down fasteners. If a graph is constructed determining the position of the misaligned shaft, you will know exactly which direction to move the machine. Another way to avoid confusion is to always look from the machine toward the machine.
- Everything to the right, or toward the 3 clock position, is in the positive direction.
- Everything to your left, or toward the 9 clock position, is in the negative direction.
This should help you visualize the proper direction for the move. The preferred and most accurate method for measuring the horizontal movement is to place dial indicators around the machine in the planes of the feet.
It is important that the indicators are positioned on the machine in the location used in the alignment calculation. This usually is the center of the hold-down bolt and at the approximate shaft height.
The procedure for performing a horizontal move of a machine is as follows:
- Position the base-mounted dial indicators in the location of the machine's feet or at the point determined from the alignment calculation.
- Adjust the dials to zero.
- Move the machine in the proper direction by the determined amount, making sure all of the dial indicators agree.
Proper Dial Indicator Setup
No matter what device or method is used to move the machine, it is very important to have control of the machine. The most common problem encountered when moving the machine horizontally is that there are no jackbolts on the machine to maintain this control. If no jackbolts are installed, small hydraulic jacks can be used to move a machine if they are backed up to a solid structure, such as a beam, a solid wall, an adjoining pedestal, or a base. A chain fall or come-along can also be used. Again, they must be secured to something solid or immovable and operated one click at a time. Another very good idea is to use pony clamps or pipe clamps, attached and operated to smoothly move the machine in the desired direction.
Before any of the hold-down bolts are loosened, all of the jackbolts must be loosened on the machine. Any unequal pressure of the jackbolts could result in an uncontrolled move and require the technician to take another set of alignment readings. When loosening the hold-down bolts, back them off just enough to allow the machine to slide sideways. Since it takes very little pressure on the jackbolt to move the machine horizontally, there is no real need to completely back off or remove the hold-down fasteners. If a graph is constructed determining the position of the misaligned shaft, you will know exactly which direction to move the machine. Another way to avoid confusion is to always look from the machine toward the machine.
It is important that the indicators are positioned on the machine in the location used in the alignment calculation. This usually is the center of the hold-down bolt and at the approximate shaft height.
Proper Dial Indicator Setup
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