FAQ

What are the advantages of using a Shim?
How does a Shim reduce costs?
How do you properly design a Shim?
What material should I use for my Shim?
What are the standard material tolerances of Shim stock?
What are some common finishes for Shims that I should consider?
What is the difference between a Shim and a Thrust Washer?
What Shims are peelable?
What is a Laminated Shim or Adjustable Shim Pack and what are the advantages?
What is a Bearing Shim?
What materials are recommended for Bearing Shims?
Does SPIROL supply Shim Stock?

What are the advantages of using a Shim?

Shims are used as compensators to absorb tolerances between mating components. They significantly reduce manufacturing time and costs as they eliminate the need for each component to be precision machined in order to achieve the proper fit and function of the total assembly. During the assembly process, Shims provide adjustment to compensate for accumulated tolerances that significantly reduces machining and assembly time. Additionally, Shims are commonly used to preserve the faces between mating components cutting down the required machining time during rebuilds / retrofitting.

How does a Shim reduce costs?

Shims can reduce manufacturing and assembly costs in two important ways:

By using a Shim to fill the gap between two machined components, you can reduce the tolerance requirements of those machined components, thus lowering machining costs.
In assemblies where vibration and wear occur, a Shim can act as a low-cost sacrificial item that will take the brunt of the damage and save wear and tear on the costly assemblies. The Shim can be replaced during scheduled maintenance or teardown.

How do you properly design a Shim?

The form of a Shim is determined by its function. Ideally, the Shim will follow the contour of the mating components. Thickness will be determined by the space the Shim needs to fill. Host material type, durability and exposure to environmental factors will determine the best material and finish for the Shim. SPIROL's Shim Specialists can provide price quotes and recommend materials and Shim configurations based on your specific requirements.

Holes can typically be within approximately 2.5mm (.1") of any other feature. This is mostly applicable to short run or prototype orders where a tooling investment does not make good business sense.

What material should I use for my Shim?

This depends on the purpose the Shim will serve. Is it a Thrust Washer, a wear plate, or a washer? Do you have to fill a variable thickness space? The answers to these questions, as well as product application, mating material, life expectancy and the environment the Shim will be subject to will determine the best material choice. SPIROL's Shim Specialists will be happy to assist you with recommendations based on your requirements.

What are the standard material tolerances of Shim stock?

Typically the tolerance of Shim stock is 10% of material thickness in most applications.

What are some common finishes for Shims that I should consider?

Most Shim finishes are designed to protect against particular environmental conditions, such as exposure to salts and corrosives, humidity and galvanic corrosion. Some of the more popular finishes are cadmium plating, zinc plating, black oxide coating and anodizing. SPIROL's Shim Specialists can recommend the most appropriate finish based on your specific requirements.

What is the difference between a Shim and a Thrust Washer?

A Thrust Washer looks like any other washer, but is actually used as a bearing. It is used in rotary assemblies (such as a gear box or axle) to control axial, or side to side motion and keeps the components aligned along the shaft or axle. Because a Thrust Washer is typically subject to high heat and wear, a hardened material is recommended. Thrust Washers can be hardened by two different methods: Through hardened Thrust Washers are heat treated to provide a consistent hardness through the entire thickness of the washer. Case hardened Thrust Washers have a softer, ductile core which reduces the likelihood of fracturing. SPIROL's Shim Specialists will help determine which type is best for your particular application.

What Shims are peelbable?

Both Laminated Shims and Edge Bonded Shims are peelable. Edge Bonded Shims are easier to peel since only the edges are bonded together, while Laminated Shims act almost like a Solid Shim since the full surface of the individual Shims are bonded together. Check out this White Paper that covers the differences between Laminated Shims and Edge Bonded Shims in more detail.

What is a Laminated Shim or Adjustable Shim Pack and what are the advantages?

There are three types of Adjustable Shims; Surface Bonded Laminated Shims, Edge Bonded Shims and Shim Packs. These Shims will compensate for any tolerance within a specific range. For example, if you know your Shim requirement is always going to be somewhere between 1.3mm - 2.5mm (.05" - .10"), SPIROL can create a Shim Pack to meet any thickness within that range. Not only is this a more convenient way of shimming your application, it reduces the physical inventory space required and reduces the number of Shim SKUs required.

SURFACE BONDED LAMINATED SHIMS are typically produced from low carbon steel, stainless steel, aluminum or brass. They are adhered throughout the entire surface between each layer of material and the layers are pressed together to cure much like how particle board is manufactured. They provide adjustability in incremental steps of 0.05mm or 0.08mm (.002" or .003") per layer.

EDGE BONDED SHIMS are individual Shims stacked up with features aligned and a thin layer of adhesive is applied to the exterior edge of the stack-up. Edge Bonded Shims are great for field service as they allow your technician to quickly and easily adjust the Shim thickness to match the tolerance required.

SHIM PACKS are similar to Edge Bonded Shims except the parts are tied together and presented as a single component. They can be created from a wide range of materials. Because tied Shim Packs can be created from multiple thicknesses, a broader range of thicknesses with tighter tolerances can be easily obtained.

What is a Bearing Shim?

Bearing Shims are used primarily to set or adjust the pre-load on the bearing races so as to ensure that the bearings roll/move as intended. Bearing Shims are different than Thrust Washers in that Bearing Shims are typically in a static application where Thrust Washers are in more of a dynamic application.

What materials are recommended for Bearing Shims?

Bearing Shims are typically produced from 1008/1010 low carbon steel depending on the application. The flatness and consistency of thickness are the critical features for Bearing Shims. The races on the bearing need to apply consistent force against the rollers in order for them to function correctly.

Does SPIROL supply Shim Stock?

SPIROL supplies a limited amount of Shim Stock. However, we do specialize in the manufacture of Precision Engineered Shims ranging from simple OD/ID shapes to complex geometries - particularly in low to medium volumes. All Shims are custom-made to customer specifications from a comprehensive inventory of raw materials in thicknesses from 0.02mm (.001") to 9.5mm (.375"). Our internal abilities are focused on making high quality Shims at a very competitive cost with short lead times. Please view or download our Shim brochure that provides more information about our Shim product line.

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