American Metals' stainless steel pre-cut slotted alignment tab shims have been used for shaft alignment of rotating equipment such as motors, pumps, fans, blowers, turbines, compressors, die stampers, punch presses, gear boxes and journal boxes in steel mills, chemical plants, paper mills, refineries, power plants, and HVAC facilities. Following is a list of suggested applications based on best practice.
| Size A 2"x 2" 17/32" Slot |
Size B 3"x 3" 25/32" Slot |
Size C 4"x 4" 1 1/4" Slot |
Size D 5"x 5" 1 3/4" Slot |
|
| BOLT SIZE | Up to 1/2" | 1/2" to 3/4" | 3/4" to 1 1/4" | 1 1/4" to 1 3/4" |
| NEMA FRAME NUMBER |
42, 48, 56, 143, 145, 162 to 169, 182 to 189, 213 to 219, 1610, 1810 & 2110 |
66, 253 to 259, 283 to 289 & 323 to 329 |
203, 204, 224, 225, 263 to 269, 403 to 409 & 443 to 449 |
502 to 509, 582 to 589, & 681 to 689 |
| HORSEPOWER RANGE |
0.25 to 15 | 10 to 60 | 50 to 200 | 150 to 1000 |
Although this table is a good starting reference on the proper size of shim to be used, the most important factor is the support of the piece of machinery being shimmed. Please double check the dimensions of the mounting feet and bolt size to insure proper support.
The emergence of oversize slotted shims has allowed for the substitution of shims with a small footprint to accommodate a larger size bolt.
Sometimes, this savings has come at the expense of support between the mounting feet and base plate.
Fig. 1 shows a fully supported machine, the shims extend beyond the mounting foot. Fig. 2 shows how using an oversized slot will accommodate the bolt size, but might not provide the proper support. This can lead to vibration problems and more frequent need of shaft alignments.
