Donovan’s custom jewelry design

10/15/2026

🔧 THE HISTORY OF THE HVAC MANIFOLD ❄️

Ever wonder where those red and blue gauges hanging off every HVAC technician’s truck came from?

The story goes all the way back to 1849, when French inventor Eugène Bourdon developed a revolutionary pressure gauge using a curved metal tube. His invention became the foundation for the mechanical pressure gauges still used today.

As refrigeration technology advanced during the early 1900s, technicians needed a way to monitor both high- and low-side pressures while servicing systems. Eventually, gauges, valves, and hoses were combined into the familiar manifold gauge set.

By the 1950s, manifold gauges were already being used to service air-conditioning systems. In 1949, Jack Ritchie introduced the yellow refrigerant charging hose that would help launch the legendary YELLOW JACKET brand.

As residential air conditioning exploded in popularity during the 1950s and 1960s, the manifold became an essential part of the technician’s toolbox.

Today, digital manifolds can calculate superheat, subcooling, and saturation temperatures automatically, but the basic concept remains remarkably similar.

More than 75 years later, the manifold is still one of the most recognizable symbols of the HVAC trade. 💪

Are you still running analog gauges, or have you gone digital? 👇

09/18/2026

Name. Date. Company name. License number. Plain Jane. Silver. Gold. Diamonds.. make it yours.

These custom pipe wrench pendants are made to represent the tradesmen who wear them—their company, their career, their accomplishments, and the years of work behind it.

From a sterling silver wrench to a fully customized gold and diamond piece can be built and personalized.

🎄 Now taking early Christmas orders. Custom work takes time, so if you’re thinking about having something made for Christmas, now is a good time to get on the schedule.
Made to represent.

09/16/2026

My mom always told me, “Don’t be the nail. Be the hammer.”

So I made the hammer. 🔨

This one is modeled after the Milwaukee T-Bone II 15 oz. Titanium Hammer—one of those tools that carpenters know, love, and recognize immediately.

I’ve always liked making jewelry that actually represents what somebody does for a living. Not just another pendant—a miniature version of the tool that earns the paycheck, builds the house, and gets s**t done.

Because once you become the hammer…

You can hammer nails.
Pull nails.
Build s**t.
Tear s**t apart.
Fix the s**t you tore apart.
And when all else fails…

Hit it with the hammer. 😂🔨.

09/13/2026

I was the last one to get out alive, but I had to agree to make HVAC related jewelry for the rest of my life.

09/04/2026

These strange-looking pliers have a story that spans generations.

Milbar safety-wire twisting pliers became a familiar tool in aviation, the military, motorsports and anywhere vibration could cause a critical fastener to work loose.

The technique is called safety wiring, or lockwiring. Stainless wire is passed through holes drilled into bolts or nuts and arranged so that if a fastener tries to turn loose, it pulls against the wire instead.

The pliers make that job fast and consistent. Clamp the two ends of the wire in the jaws, lock them closed and pull the k**b at the bottom. An internal spiral mechanism spins the entire tool, twisting the wires together into a tight, uniform twist.

Wire-twisting tools date back more than a century, and by the 1950s specialized designs were being patented to make aircraft safety wiring faster and more consistent. Milbar became one of the names most closely associated with the tool.

One of my favorite pieces of Milbar history is the story of a pair issued to an Air Force aircraft mechanic during the Korean War. He used them working on B-29s and later became a B-52 crew chief. Years later, his son joined the Army as a nuclear-warhead specialist and was issued Milbar safety-wire pliers in his own toolbox. He later joined the Marines and encountered them again while working on Harrier aircraft.

Different generation. Different branch. Different machine. Same tool. Same purpose.

That’s what makes these pliers interesting. They’re basically a mechanical insurance policy—no electronics or sensors, just a simple tool and a piece of wire keeping critical hardware from coming loose.

Sometimes the smallest detail is what keeps the entire machine together.

Made to Represent.
Crafted to Last.

09/02/2026