Archive: Oct 2026

Case Study: Precision Lapping for an Aerospace Sealing Application

Peerless Precision President Kristin Carlson has a saying she likes to break out from time to time: “Not every problem in the world can be solved by lapping… but a lot of them can.” Lapping is an extremely valuable problem-solving tool in manufacturing because it can produce flat surfaces and finishes that other processes struggle to achieve.

Our experience with one aerospace customer’s sealing requirement shows the point perfectly: the right lapping expertise can solve a surface-finish problem that other processes cannot.

The Challenge: Creating a Cryogenic Seal

Several years ago, an aerospace manufacturer contacted Peerless Precision about components intended for a lunar lander. The parts would have to stand up to the extreme conditions of space, and that required precise fits and extremely smooth sealing surfaces.

The parts needed to create a cryogenic seal, but the manufacturer was having difficulty achieving the necessary surface finish consistently. The specification called for a 2 µin Ra finish, which can be a significant challenge for many manufacturers. They had already approached other shops, but none had been able to produce the result consistently.

As they had researched potential solutions, they learned about our lapping services and contacted Peerless Precision to see whether we could help.

Step 1: A Carefully Controlled Trial

Because the customer was located in our region, we invited them to bring the parts to our facility so that we could evaluate them. After seeing the parts and discussing the issue with them in person, we believed lapping could produce the necessary finish.

Even so, with a challenging new part like that, we wanted to validate the process before committing to production. Instead of immediately committing to a production order, we proposed a trial with one piece each from four part numbers.

This way, we could be sure we were able to meet their requirements and determine the processing time for each part. They paid for time plus materials as a simple and fair pricing structure.

Achieving the Finish Through Manual Flat Lapping

The trial parts turned out beautifully. Our team achieved the specified surface finish across all four samples, giving the customer the confidence to move forward with production orders.

The components were round but included flat sealing surfaces that required finishing. Each part was flat-lapped manually, a process that requires significant operator skill and control. The operator must understand how the part is responding throughout the process and know when the surface has reached the required condition. A completely manual operation like that requires an experienced technician.

A Specialized Solution for Aerospace Machining

Since then, the customer’s team has continued manufacturing the parts at its own facility, then shipped them to Peerless Precision for the specialized lapping operation. They’ve stayed a consistent customer ever since.

Some exceptionally smooth surfaces are far easier to achieve with lapping as a secondary finishing process instead of using conventional machining alone. But today, relatively few machine shops continue to offer lapping, and even fewer have the experts on staff to get repeatable results.

As Kristin jokes, lapping may not solve every problem in the world, but it was exactly the right solution for this aerospace application, and for many others. If you have a challenging surface finish requirement, request a quote from Peerless Precision today to discuss your project.