TMAS shims: sizes, thicknesses and how to choose them

TMAS shims are steel sheets of precise thickness that are placed under the feet of a machine to correct unevenness and achieve correct alignment. They are also known as alignment shims or shims. Their main function is to fill the gaps between the machine base and the foundation, so that the equipment is level and the axes are well aligned.

These shims are used in pumps, electric motors, compressors, gearboxes and any rotating equipment that needs a firm and even base. Poor leveling generates vibrations, premature bearing wear and coupling failures. Therefore, in assembly and maintenance tasks, having shims of known thickness is essential to do a neat and lasting job.

SKF manufactures these shims within its line of mounting and maintenance tools. The TMAS series includes different plate sizes and thicknesses that are identified with a specific code. The code of each shim identifies its size and thickness, which allows selecting the exact combination required by the aligner or the installation drawing.

The first data for choosing a TMAS shim is the machine foot size. The shim must be large enough so that the foot rests completely on it, without protruding edges or areas without support. If the shim is smaller than the foot, the load is concentrated in a smaller area and it deforms; if it is much larger, it can interfere with other components or with the foundation.

In addition to the size, the position of the anchor bolt must be considered. The shim usually has a slot or shape that allows it to be passed around the bolt without completely disassembling the machine. The slot allows it to be inserted or removed without lifting the equipment too much. This speeds up the work and reduces the risk of moving other support points.

To order a TMAS shim, the most practical is to indicate the full code, which identifies the size and thickness. For example, TMAS 100-050 corresponds to a shim of the 100 series with a specific thickness. If you don't have the code, you can send us the foot size and bolt diameter, and we will help you identify the correct shim.

When the aligner indicates a height correction, it rarely matches the thickness of a single shim. It is usual to combine several shims to achieve the exact thickness. The key is to use the fewest number of shims possible, prioritizing the thickest ones and completing with the thinnest. This reduces the risk of air gaps or shims sliding against each other.

A common mistake is to stack many thin shims to reach the same thickness. This increases the possibility of burrs, dirt or irregularities accumulating between layers, which affects the rigidity of the support. The correct way is to use a thick shim as a base and add one or two thin ones for fine adjustment. A flat and clean shim rests well on the next one.

To order a combination, you can indicate the codes of the shims you need. For example, if the aligner requires a thickness greater than that of a single shim, you can combine TMAS 100-100 with TMAS 100-050 and TMAS 100-005. We quote each shim separately or we assemble the complete group according to your need.

For frequent alignment work or for maintenance workshops, TMAS shim kits are a practical option. They gather a range of thicknesses in a single case, which allows solving different corrections without having to order individual shims each time. Among the kits in the series are TMAS 50/KIT, TMAS 75/KIT and TMAS 100/KIT, as well as the cases TMAS 340, TMAS 360, TMAS 510 and TMAS 720.

The advantage of the kit is that you have at hand a range of thicknesses to try until achieving the exact height. In an alignment, you often start with an estimate and then adjust with thinner shims. With the kit, that adjustment is made on the spot, without waiting for a shim of a specific thickness to arrive.

If in your plant you align machines with similar foot sizes, a kit of the appropriate size will serve you for most jobs. If instead you have a very large equipment or a specific correction, you may prefer to order only the individual shims you need. At MR we advise you to choose the most convenient option according to your case.

To order a TMAS shim, the most direct is to use the full code that appears in the catalog or on the shim itself. For example, TMAS 50-050, TMAS 75-050 or TMAS 200-200. That code identifies the plate size and thickness, and allows us to quote the exact part without confusion.

If you don't have the code, you can send us a photo of the shim you are replacing or the machine foot measurements. With the length, width and approximate thickness, we will indicate which code of the TMAS series corresponds. It is also useful to indicate the bolt diameter.

At MR we market and distribute SKF TMAS shims. You can write to us via WhatsApp or email with the code, measurements or a photo, and we will quote you promptly.

TMAS shims are precision tools, and as such they must be kept clean and flat. Before using them, check that they have no burrs, dents or adhered dirt. A small burr can alter the actual thickness and cause the machine to be uneven even if the combination of shims is correct.

After using them, it is advisable to store them by size and thickness, in a dry place protected from dust. If you leave them loose in a toolbox, it is easy for them to get scratched or mixed. If you work with a kit, return each shim to its place to maintain order and quickly find the one you need.

A common mistake is to reuse shims that have been exposed to the weather or that were bent when disassembling a machine. A deformed shim does not rest well and can distort the aligner reading. If you have doubts about the condition of your shims, you can consult us and we recommend replacing them with a new shim of the same size.

At MR we work with SKF TMAS shims, both individual shims and kits. If you already know the code, send it to us and we will quote you promptly. If not, tell us what machine you are aligning and what thickness you need, and we will help you assemble the order.

You can write to us via WhatsApp or email with the shim code, foot measurements or a photo of the part. Our team will indicate the best option according to the size and thickness you need. We also advise you on the most appropriate combination of shims for your alignment job.

TMAS shims are a key input for the assembly and maintenance of rotating equipment. Order them with the exact code and make sure you have the correct size to leave the machine well leveled. At MR we help you choose the correct size.