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A Guide to Shim Stock

Many industrial tasks require precise positioning. In precision machining, for instance, both tooling and workpieces must be placed in exactly the right positions to achieve desired tolerances. These kinds of applications require shims—small strips of metal used to fill gaps between components to create a tighter fit or more level surface. Shims come in many shapes and sizes to meet various positioning requirements. 

Although shims can be made from plastic or rubber, most are cut from very thin sheets of metals known as shim stock. Trinity Brand Industries offers a full catalog of metal shim stock materials, including carbon steel, stainless steel, brass, bronze, copper, aluminum, titanium, and electrical steel. To complement these options, we also offer punch-and-die sets so that clients can easily create consistent shims with minimal waste. Regardless of the application, we can supply you with the shim stocks you need to achieve proper precision and productivity.

What is Shim Stock?

A shim stock is a roll of thin gauge metal or foil used to create shims. Thin gauge cut sheet metal may be as thin as 0.0005 inch (0.0127 millimeter) to allow for fine positioning adjustments.

Since the material is so thin, stock can easily be cut into custom shapes using standard tools such as metal shears. For more complex shapes, or to achieve greater precision, users may also rely on stamping, laser cutting, water jet, machining, or other metal fabrication processes to customize their shims. Common stamped shapes include rings, which improve alignment and prevent axial motion, U-shaped slotted shims, which fit around screws to align and level equipment and flat shims to adjust the height of die sets.

How to Use Shim Stock

Shim stock is easy to adapt to any application, and the general process is similar whether you’re using sheets, rolls, or pre-cut shims.

  1. Determine the necessary shim thickness. Use feeler gages of increasing thicknesses to determine how large a shim will be required. 
  2. Select the right shim stock. The previous measurement determines the ideal shim stock size for your application. In some cases, you may need to stack shims to achieve sufficient elevation, but use caution when combining more than four shims or when dealing with gaps larger than 0.15 inch. You should also choose the right type of metal for your setting. For example, in a highly corrosive environment, you might opt for stainless shim stock sheets. 
  3. Cut the shim stock. Unless you’re working with a set of pre-cut shims, you will need to cut individual shims from the roll or sheet. For simple shapes, use metal shears. For more complex shapes, use a stamping kit or a dedicated press.
  4. Position the shim or shims. Finally, slide the shims into place and proceed with your process.

Common Shim Stock Materials

Metal shims can be made from a wide range of materials, and the best choice depends on the application constraints.

  • Stainless steel: Stainless steel is one of the most versatile metals, offering a balance of strength, hardness, and corrosion resistance with each fabrication. Stainless steel is distinct from carbon steel because it includes chromium as an alloying element, which grants excellent corrosion resistance. Stainless shim stock creates strong, durable shims suitable for corrosive or outdoor environments and marine applications.
  • Electrical steel:  Electrical steel refers to certain steel alloys engineered to have beneficial magnetic and electrical properties. The inclusion of silicon in varying proportions increases permeability and resistivity while decreasing magnetostriction. These alloys can be either grain oriented or non-grain oriented, depending on their method of production.
    • Grain oriented electrical steel: Grain oriented steel has optimized magnetic properties only in the direction it was rolled.
    • Non-grain oriented electrical steel: Non-grain oriented steel has good magnetic properties in all directions, rather than just in the rolled direction.
  • Steel: Steel shims are among the most common, especially for indoor applications. 
    • Carbon steel: In contrast to stainless steel, carbon steel alloys have carbon as their primary alloying element rather than chromium. Low, medium, and high-carbon steels are available, with high-carbon steel being harder but less ductile than low-carbon steel.
    • Blue tempered steel: Blue tempered steel is a form of high-carbon steel known for its high yield strength and high fatigue strength. It also has excellent thermal and electrical conductivity.
    • 1095: 1095 is a high-carbon steel that features good strength, hardness, and durability. It can be ground to very tight tolerances for precision applications.
    • 1075: 1075 has similar properties to 1095 carbon steel, although it has a lower carbon content. As a result, it is slightly softer but also more formable.
  • Aluminum: Aluminum is best known for its excellent strength-to-weight ratio. It is also corrosion-resistant and highly formable, so it can be used to form intricate shapes. Aluminum shim stock is best used where weight is a significant concern.
  • Brass: Like aluminum, brass is another non-corrosive, non-magnetic, and highly formable metal. Brass shim stock is popular for technical applications and electrical conductivity. 
  • Bronze: Bronze is a strong, formable, and ductile alloy of copper. Bronze shim stock has excellent corrosion and fatigue resistance as well as good electrical properties, so it is a popular choice for electronic applications.
  • Copper: Copper is known for its ductility and electrical and thermal conductivity, which also make it a common material in the electronics industry. Copper shim stock is also highly resistant to corrosion, so it can be used outdoors or in corrosive environments.
  • Titanium: Titanium is a low density metal with an extremely high strength-to-weight ratio. It also resists corrosion from many different chemicals, including chloride and chlorine-based substances. Used in aerospace and aircraft applications.

For help selecting the right shim stock for your needs, consult our full list of materials found in our product guide

Shim Stock Applications and Industries

Shims can fill small gaps between components, elevate materials to be machined, align parts during repair, and more. As a result, shims are used in a diverse range of industries.

  • Aerospace: Shims are frequently used to achieve the tight tolerances necessary in the aerospace industry or to position components for repair. In these settings, strong and corrosion-resistant shims are critical. 
  • Automotive: In the automotive industry, shims are used in both manufacturing and maintenance. They can adjust valve clearances or other spaces between parts. High-nickel bronze and brass shims are especially ideal for EV applications.
  • Oil & Gas: Shims are useful for absorbing accumulated tolerances in pumps and motors, aligning mated components, and acting as thrust washers.
  • Medical devices: Shims help establish and maintain the pinpoint tolerances needed for implanted medical devices, prosthetics, imaging equipment, and surgical robots. 
  • Marine: Corrosion-resistant stainless and brass shims are ideal for aligning and positioning applications within the marine industry.

Metal fabrication techniques such as laser cutting, waterjet cutting, machining, and stamping can be used to customize shims to suit these diverse applications. In addition to providing shim stock and tooling, Trinity Brand Industries performs comprehensive metal fabrication services to craft precision shims.

Shim Stock Solutions at Trinity Brand Industries

Shims play an essential role in helping clients achieve proper positioning and alignment for their projects. Shim stock is useful both for fabricators, who use the materials to create custom shims, and for end-users, who can quickly stamp or cut shims on-site. At Trinity Brand Industries, we are committed to supporting both types of users.

We offer a full range of standard and hard-to-find materials with custom cut dimensions, which you can learn more about in our product guide. We cater to both small and large-scale distributors, offering competitive pricing on orders ranging from several pounds to several metric tons. Whatever your application, TBI has the experience and sourcing network to meet your needs.

To learn more about our shim solutions—which include shim stock, pre-cut shims, and stamping tools—contact us or request a quote today.

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