FlexTrades works with manufacturers of all kinds — from aerospace and automotive to food production. Some of our clients make frozen pizza. Others make snack cakes, breakfast foods, plant-based proteins, or prepared meals. The point is, we’re all pretty spoiled by the convenience of walking into a grocery store and grabbing whatever we want — frozen, fresh, or refrigerated.

But it wasn’t always like this.

Before the modern freezer, cold food storage meant digging holes in the ground, building underground cellars, or relying on blocks of lake ice stored in ice houses. The result? Slow freezing. That process formed large ice crystals, which caused food to become watery and tasteless once thawed.

Enter: Clarence Birdseye, the man who changed the game.

Clarence Birdseye: The Father of Frozen Foods

Clarence Birdseye got his start not in food, but in fur trading. While working in Canada, he noticed that fish caught by local Inuit froze instantly in the subzero air. Even months later, once thawed, the fish tasted just as fresh.

That moment of observation sparked a theory — fast freezing retains food’s texture and flavor better than slow freezing. Clarence tested his theory and proved it right, not once but twice.

Birdseye’s First Method: Calcium Chloride Brine

In his first innovation, Clarence developed a process using calcium chloride. Here’s how it worked:

  • Packaged food was placed between two metal belts
  • The belts were cooled to between -40°F and -45°F using a calcium chloride solution
  • The food froze almost instantly

This led to his first business — Birdseye Seafood — where he patented his process for freezing and storing fish.

His system included:

  • A refrigerating tank with calcium chloride brine
  • Containers to freeze fish fillets into solid blocks
  • Wax paper packaging for preservation
  • An insulated shipping container, later used in refrigerated railcars and grocery store display cases

Fun fact: Clarence also patented his refrigerated boxcar, laying the groundwork for modern cold-chain logistics.

From Bankruptcy to Breakthrough

Birdseye’s first venture went bankrupt. But he didn’t quit. He sold his and his wife’s life insurance policies and secured investment funding to launch again — this time with General Seafood Corporation in Gloucester, Massachusetts.

There, he developed a second freezing method, and this one stuck.

Birdseye’s Second Method: Ammonia and Innovation

This method used ammonia evaporation instead of calcium chloride. The process:

  • Packaged food was placed between hollow metal plates
  • Ammonia chilled the plates to between -25°F and -40°F
  • Fruits and vegetables froze to 0°F in 30 minutes, meats in 75 to 90 minutes

In 1929, Birdseye sold General Seafood Company — along with his fast-freezing patents — to Postum Cereal Company for $22 million (over $358 million today). Postum changed its name to General Foods Corporation and made Clarence president of its new Birds Eye Frosted Foods division.

Soon after, Birds Eye began rolling out frozen spinach, cherries, meats, and peas. That was just the beginning. Today, Birds Eye makes everything from frozen vegetables and sauced sides to full skillet meals and cauliflower wings.

An Inventor, a Naturalist, and a Relentless Innovator

Birdseye’s story began in Brooklyn in 1886. At age 10, he started his first business by trapping muskrats and selling them to a British lord. At Amherst College, he sold frogs to the Bronx Zoo to pay tuition. When that didn’t work out, he became a fur trader in Labrador and later worked as a naturalist for the U.S. government in the Arctic.

That’s where he got the idea that changed food manufacturing forever.

Through it all, Birdseye remained humble. His words say it best:

“I do not consider myself a remarkable person. I am just a guy with a very large bump of curiosity and a gambling instinct.”

Want to Learn More About Food Manufacturing?

Check out the FlexTrades blog for more How It’s Made stories — including articles on mystery flavored suckers, cheese, plant-based burgers, and even Spam

Every technician has a toolbox. Wrenches, pliers, screwdrivers — the mechanical staples are easy to recognize. But if you work in manufacturing, especially in quality or machining roles, there’s another set of tools that matter just as much: inspection tools.

These tools ensure the work you perform isn’t just done — it’s done right. And while some are provided by the employer (due to cost or required calibration), every technician should understand what these tools do and why they matter.

This is our version of the Essential Technician Toolbox, focused on quality operations.

Inspection Tools You Should Know

Calipers

Used to measure the inside diameter (ID) and outside diameter (OD) of components.

Types include:

Gauges

Used for quick, reliable dimensional checks.

  • Thread Gauges – also called screw or pitch gauges; measure thread pitch
  • Go/No Go Gauges – include plug, snap, and ring gauges for checking pass/fail limits (see the differences)
  • Chamfer Gauges – measure top diameters of tapered or chamfered holes
  • Depth Gauges / Depth Micrometers – measure holes, slots, and cavities
  • Height Gauges – measure and set vertical distances

Hardness Testers

Used to determine the Rockwell Hardness of materials. The method depends on the type of metal or alloy being tested.

Indicators

Help align parts, inspect roundness, or assess surface irregularities.

  • Dial Test Indicators
  • Plunge Indicators
  • Travel Indicators

Micrometers

Precision instruments that measure thickness, depth, and length — more exact than calipers.

Surface Comparators

Used to visually compare and measure surface roughness or finish.

Surface Plates

Granite or cast iron blocks that provide a perfectly flat reference surface for checking whether an object is flat, convex, or concave.

Tool Tidbits: Analog vs. Digital and Metric vs. Imperial

Many of the tools listed above come in both analog and digital formats. Think of it like this:

  • Analog tools = like a watch with hands
  • Digital tools = like a digital clock, giving precise numbers at a glance

Similarly, these tools may use metric or imperial systems. Not sure what that means? Check out this guide.

Calibration Matters

Accuracy is everything. That’s why inspection tools must be regularly calibrated. Calibration ensures that your readings are reliable, consistent, and within tolerance — because trust in the tool means trust in the work.

Who Uses These Tools?

If you’re in any of the following roles, these tools are part of your world:

  • CNC Operators
  • CNC Machinists
  • Quality Inspectors
  • CMM Programmers
  • Machine Operators

These professionals rely on inspection tools during pre-inspection, in-process checks, and final inspection to make sure every part meets spec.

Because in manufacturing, it’s always safety first, quality second — and these tools help protect both. 

In manufacturing, people often think that production volume is the top priority. That’s a mistake.

At FlexTrades, we know the truth: safety always comes first. And right behind that is quality — because without quality, production numbers don’t matter.

Critical to achieving consistent, measurable quality is a powerful piece of equipment: the CMM.

Let’s take a closer look at what CMMs are, how they work, and why they matter.

What Is a CMM?

CMM stands for Coordinate Measuring Machine. These machines are used to measure the physical dimensions and geometric characteristics of manufactured parts.

Yes, those same measurements can be done with precision hand tools. But manual inspection leaves room for error. People get tired. Vision blurs. Mistakes happen.

CMMs eliminate that guesswork by automating the inspection process. At a basic level, a CMM includes:

  • A stable platform or table to position the part
  • A probe that performs the measurements
  • A computer program that guides and controls the probe’s path

But as simple as that sounds, there’s more going on under the hood.

CMM Programming: Where Precision Begins

CMMs are only as smart as the code that runs them.

CMM programming is a specialized form of machine instruction. Programmers create sequential sets of directions that tell the probe where to move, what to measure, and how to measure it.

Some parts only require a few basic measurements. Others have hundreds of features that must meet tight tolerances. Regardless of complexity, the program must be flawless — because CMMs can’t measure anything they haven’t been told to inspect.

CMM programming is done using software specifically designed for this task. If you’re not a programmer, it might look like a foreign language. But to a trained CMM programmer, it’s a tool for perfection.

What Does a CMM Programmer Do?

A CMM Programmer writes the detailed code required to inspect parts accurately and efficiently.

That includes:

  • Mapping the inspection path
  • Defining each feature and tolerance
  • Ensuring alignment between design specifications and machine behavior

As machined parts become more complex — with intricate geometries and tighter tolerances — the job only gets harder. CMM programmers play a key role in maintaining quality and reducing waste across the entire production cycle.

Interested in Becoming a CMM Programmer?

If you’re looking to break into this field, start by exploring programs in Quality and Manufacturing Technologies. Many trade schools and technical colleges offer degrees or certificates in these areas.

Once you’ve got the education, hands-on experience is next. Common starting points include:

  • CMM Operator
  • Quality Inspector
  • Machine Operator with inspection responsibilities

If you’re already in manufacturing, let your interest be known. Many CMM programmers start out on the floor and transition into programming roles through on-the-job training.

Already a CMM Programmer or Operator?

FlexTrades is hiring skilled professionals like you. Join our team and get access to:

  • National travel opportunities
  • Advanced technology and equipment
  • Flexible schedules
  • Industry-leading manufacturers

Apply here and take the next step in your career. 

At FlexTrades, we provide workforce solutions to American manufacturers. It’s what we do — and we take the solution part seriously.

That means we ask a lot of questions. But we also answer a lot, especially from the skilled trades community. This post tackles some of the most frequently asked questions we hear from technicians and job seekers alike.

Do I Need a Forklift Certification?

This is one of the most common questions we get. And the answer is straightforward:

No, you don’t need an active forklift certification to qualify for a FlexTrades project.

But — and it’s a meaningful but — having prior forklift experience or past certification is highly preferred.

Here’s why: any technician operating a forklift on a project will need to certify to that client’s internal standards while onsite. So while FlexTrades doesn’t require your certification to be current, previous certification makes you a stronger candidate and helps you hit the ground running.

Are There Other Required Certifications?

Yes, there are a few other certifications that occasionally come into play:

  • OSHA safety certifications (Occupational Safety and Health Administration)
  • MSHA safety certifications (Mine Safety and Health Administration)
  • CDLs (Commercial Driver’s Licenses) for roles involving transportation or heavy hauling

These certifications aren’t required for every project, but when they are, having them in hand puts you at the top of the list.

What Other Certifications Should I Consider?

Beyond the essentials, there are plenty of optional certifications that can make you more competitive in the skilled trades.

Want to get ahead? These resources can help:

Certifications can lead to better roles, higher wages, and more career mobility.

Want to Work with FlexTrades?

If you’re a recent graduate of a technical training program, consider applying through the FlexTrades ReTool Program. It’s designed to help you bridge the gap between training and the real world.

Already have experience? Join our Talent Network to access new projects, grow your career, and work with top-tier U.S. manufacturers.

Have a Question of Your Own?

We want to hear it. Send your questions to writingteam@flextrades.com and we’ll answer them in a future FAQ.