This isn t really more complex than an evenly-spaced bolt pattern in a circle other than whatever difficulty may be encountered in securing measurements of the bolt pattern you are assigned to deal with. The bolt pattern in FIGURE (1) isn t at all typical, but it is definitely random. At three inches to the square, I count approximately 37" from East to West and 33" from North to South in the overall bolt pattern.

The use of a graph is a very accurate method of plotting such a bolt pattern from measurements, and it literally provides the mechanic with a graphic view of the problem at hand.

Beginning with bolt #4 in FIGURE (1), #4 gets zero shims for the East to West shim calculations. (This is because of the positive .012" West reading of the face indicator). Bolt #4 becomes a pivot point with zero shims. Then all bolts West of #4 will have shims added in direct proportion to their Westerly distance from bolt #4. See block #4 in FIGURE (2). The next bolt west is #5, and at two squares West of #4, this translates into 6". Therefore, 6" is used in the following formula for the East/West angular correction for bolt #5:

Where:

• WR=the West reading on the face indicator (+.012" in this case)

and:

• 6"=the East/West distance between bolts #4 and #5

and:

• ID=the indicator circle diameter (12" in this case)

Then:

Place .006" in block #5 prefixed with a +. See FIGURE (2)