A Guide to Shims and Their Types

A shim is a thin, tapered or wedged piece of material used to fill small gaps or spaces within objects. They are commonly used to support, adjust for better fit, or provide a level fit. In many cases, shims are also used as spacers to fill gaps between parts subject to wear and tear. The material a shim is made from is known as shim stock. Common shim stock can be made from a variety of materials but is typically composed of wood, stone, plastic, metal, or even paper. Aerospace specific shims come from materials such as carbon steel, stainless steel, brass, copper, aluminum, titanium, and others.

Shims used in the aerospace industry typically serve as washers, motor and vibration mounts, and seals. Aerospace shims are subject to a great deal of pressure and stress in travel and thus must be strong and resistant to corrosion. They are found all throughout aircraft in areas including aircraft turbine engines, pilot control assemblies, landing gear, aircraft hydraulic systems, auxiliary power units, control systems, and more. Shims are integral in many different parts throughout a wide range of industries and applications. As such, there are many different types of shims. In general, there are four main types, each serving different purposes. They are: traditional shims, tapered shims, peelable shims, and edge bond shims.

1. Traditional Shims

As described above, a traditional shim is a thin piece of material placed in small spaces or gaps to fill them. Traditional shims are designed into the assembly as pre-planned parts. Therefore, they are not adjustable and are designed with a specific thickness, length, width, etc. in mind.

2. Tapered Shims

Tapered shims are used to fit between surfaces with tapers. These can make the assembly tight by pushing the pieces apart. Tapered shims can also achieve this by pushing into the assembly with the rest of the shim designed into the assembly.

3. Peelable Shims

A peelable shim comprises flat, three-dimensional layers that are glued together so the technician can peel away layers until the perfect thickness is achieved. The individual layers are exceedingly small, roughly two to three thousandths of an inch thick.

4. Edge Bond Shims

An edge bond shim is measured for inaccuracies. Technicians using this type of shim will pull off one to three layers of the shim to compensate for machining errors, whereas other products are designed into the assembly before any layers are removed. These shims are designed to fit into certain spaces, but come as part of an assembly package. Edge bond shims are for very slight adjustments between parts being assembled. Typically made from foil, 20-80 layers are cut out using CNC (computer numerical control) machining, EDM (electrical discharge machining) wire cutting, and other processes. The foil layers are put in place and the edges are glued with aerospace-quality adhesive. Following this, the layers are peeled off to exactly fit the assembly’s specifications.

How Shims are Used In Aerospace Industry?

Shims have a wide range of uses in the aerospace industries. They are found in pilot control assemblies, cockpit pedestal assemblies, engine space compensators, landing gear wear components, auxiliary power units, hydraulic actuators for flight surfaces, and in many other parts. Despite their small size, they play a key role in the function of many crucial machines. Because of this, it’s important to get shims from a trusted source like Complete Sourcing Solutions.

At Complete Sourcing Solutions, owned and operated by ASAP Semiconductor, we can help you source all types of shims and aircraft spacers and deliver them with short lead times and competitive prices. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@completesourcingsolutions.com or call us at +1-714-705-4780. Our team of dedicated account managers is standing by and will reach out to you in 15 minutes or less.

1. harry walker
2. Posted on July 24, 2020
aviation

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