shrink fitting

Cryogenic Shrink Fitting Services by Nitrofreeze®


Nitrofreeze provides shrink fitting services for aerospace, defense, and medical device customers. We specialize in small batches of less than one hundred parts and work with aluminum, steels, and exotic alloys. If you lack the expertise and know-how to work with cryogenics, why not request a quote for our shrink fitting services? Keep reading to learn more.

What is shrink fitting?

Shrink fitting uses variations in temperature to temporarily change the dimensions of parts so that they fit and hold together. This joining technique supports a tight, reliable fit between inner and outer parts in assemblies such as:

  • Aerospace components
  • Defense systems
  • Industrial assemblies
  • Tooling
  • Bearings and bushings in housings

With these and other applications, shrink fitting can prevent relative motion between inner and outer components or allow the transmission of force between them.

What are the advantages of shrink fitting?

Shrink fitting isn’t the only way to join mating parts, but it provides cost-saving advantages over traditional fastening and press fitting methods. For example, parts that are shrink fit require less machining time since they don’t require turning operations to produce keyways or threads. There’s also a labor savings during product assembly since there are no screws to turn or welds to make.  Ultimately, the Nitrofreeze shrink fitting process allows companies to achieve geometries not possible with machining a single-piece component.

How is temperature used in shrink fitting?

Shrink fitting relies upon thermal expansion and/or thermal contraction resulting in fractional changes in size that occur when heating or cooling is applied.

Nitrofreeze® cryogenic shrink fitting utilizes cooling instead of heating for temporary changes in dimensions. Importantly, these dimensional changes can be held to very tight tolerances. When the tightest tolerances are required, shrink fitting will require cooling one part and heating the other component. The cryogenic shrink fitting process exploits the coefficient of thermal expansion in various materials.

How does cryogenic shrink fitting work?

Compression shrink fitting, as this technique is also known, cools the smaller part to a freezing cold temperature. The cryogen, the substance used to produce this low temperature, is typically solid carbon dioxide or liquid nitrogen. The time required for cooling varies and is largely a function of the part’s weight and material. With some metals, such as steels, pre-treatment or post-processing may be needed.

What’s an example of shrink fitting for aerospace and defense?

The pictures that accompany this article show parts that Nitrofreeze® shrink fit for a military aviation customer. The inner part is a shaft that was cryogenically shrink fit for insertion into a toolholder. The finished assemblies are used in the landing gear for a jet fighter. Nitrofreeze® provided shrink fitting services for assemblies requiring a tight tolerance fit, all of which must perform reliably under demanding conditions.

cryogenic shrink fitting

Choose Nitrofreeze® shrink fitting services

Nitrofreeze® Cryogenic Solutions of Worcester, Massachusetts has been providing shrink fitting services for 20 years. Since our founding in 2002, we’ve completed hundreds of shrink fitting jobs for defense contractors, research laboratories, and multinational corporations. Whether you need cryogenic shrink fitting, induction shrink fitting, or both, we are ready to apply our expertise to your project.

To learn more, contact Nitrofreeze® at the phone number and email below. The consultation is free.

(508) 459-7447 x105 |