A Retrospective Of Early Boring Tools As They Shaped Today's HDD Tools
This article was also published in Trenchless Technology's August 2026 Issue.
The Fish-Tail Bit Era
My father started the company in 1946. Before that, he worked for Baker Oil Tool, which manufactured cutting tools for drilling oil wells. One of the tools they produced was a fish-tail bit. When he left Baker, he miniaturized the system and made key adjustments to the design for horizontal earth-boring applications. That became the foundation of the company. He initially produced three sizes of fish-tail bits. The primary bit cut a 2-inch hole and used a 7/8"-9 NC thread, which eventually became our standard connection. The bits were hard-faced and included a water passage through the center.
He also produced larger bits that threaded directly onto 1½-inch and 2-inch electrical conduit. Contractors used the conduit itself as the drill rod to install street-light conduit beneath sidewalks and roadways. They drilled from pothole to pothole. Once they reached the other side, they simply removed the bit and the conduit was already in place. About every fifty feet, you'd expose the drill head, sight your alignment, adjust it with a shovel or pry bar, and continue. It was mechanically guided—not electronically located and remotely guided.
The First Earth Boring Machines
Keep in mind that the machines were evolving alongside the tooling.
In the early days, there were very few drilling machines. The original machine was basically a handheld pneumatic air motor—about three horsepower—with water running through a swivel back into the drill rod. The air motor provided the torque to spin the bit, while 2 men physically pushed on it to create the thrust. Drill rods were commonly ten or twenty feet long. Everything was very simple.
One thing we learned was how important rotational speed really was. Small pilot holes needed high RPM to stay straight. When we developed our stand-alone drill rig, the DynaMole, we designed it to run around 350 RPM. Later drill rigs that entered the scene emphasized torque over speed and ran at around 70-100 RPM. The DynaMole’s higher-speed design drilled straighter.
At first, no one was using drilling fluid additives. Contractors drilled dry or with only water. As contractors encountered more clay soils, many began adding a small amount of dishwashing soap to the water. That was the mud system.
As bores became longer, especially after polyethylene pipe became more common, fluid management became more important. Bentonite and other additives helped control mud viscosity, carry cuttings downhole, preserve bore integrity, and reduce excess pressure and pullback force. When cuttings do not move properly, pressure can build, and pullback force can increase, creating risks such as pipe stretch or installation damage. Bentonite mixing systems made drilling in sand, clay, and other materials much more practical and safer.
Polyethylene Pipe Changes Everything
After my brother and I joined the company in the early 1960s, we started working closely with Southern Counties Gas Company. Then DuPont introduced polyethylene gas pipe. That changed everything. Before plastic pipe, gas lines were steel. Every joint had to be hand-welded, making installations slow and labor-intensive. Plastic pipe came on reels of 1,000 or even 2,000 feet, making much longer bores practical.
That's really where modern horizontal earth boring began. As contractors installed more plastic pipe, the gas company began bringing us problems from the field.
One example came from Pasadena, California. The sticky clay kept plugging the small water holes in the fish-tail bits. So we redesigned the bit. Instead of a small 3/16-inch water hole, we moved the outlet into the eye of the bit and increased it to roughly 7/16 inch. Water gushed through that larger opening, and because of its location, clay couldn't pack into it. That became the next generation of bit.
Then contractors started running into tree roots. So we modified the bit again. We sharpened the cutting edges and added tungsten carbide cutters along the leading edges. That allowed contractors to cut through roots—especially the fine palm tree roots common around Pasadena. Again, the tooling evolved because contractors encountered a new problem.
Every New Problem Created a New Tool
There was not anything close to what you would call “competing” HDD tool suppliers back then. There wasn't really even an industry at that point. We were the only company making these kinds of tools, and occasionally someone would weld together their own bit or coupling, but there weren't any manufacturers specializing in earth-boring tooling.
We learned a lot of lessons in those early years by staying on the jobsite with the people using the tools and listening closely. The work kept changing, and every new problem forced the tooling to change with it.
The Evolution of The Reamer
What drove the development of reamers? It was all about accuracy to begin with, not just hole size. Back then, we had no electronic steering. You wanted the smallest pilot hole possible because a small hole kept the drill rod tracking straight. Once the pilot hole was complete, you pulled back a reamer to enlarge it to the finished size.
One of my father's early innovations was the reamer with a replaceable blade body. He forged blades with a trip hammer, hard-faced them or added carbide, and you could install different blade sizes onto one body.
When I later left Melfred, I didn't have a forging hammer. So I redesigned the blade system so everything could be manufactured with a cold saw instead.
One problem with replaceable-blade systems was that sticky clay packed around the bolts until the whole tool became a giant ball of mud. After starting Borzall, I developed what became known as the Chopper reamer. At first we tried three blades, but clay packed between them. With only two blades, the clay cleared itself much better. The two-blade versions became excellent for clay, while four-blade versions worked better in rocky conditions.
Introduction Of Electronics Into Directional Drilling
Eventually, the directional part of “directional drilling” started to take on more meaning than mechanical redirection. There was a company that made regular pipe locators for locating underground pipes. Then they developed a small transmitter that could reach depths of only about 20 feet. It was very basic. It gave you beeps. When the transmitter rotated, you wouldn't hear much. When it stopped at the 6 o'clock position, you would get a solid beep.
We developed a very rudimentary transmitter housing to hold that little 8-inch sonde at the end of the drill rod. To create steering, we welded a flat piece of 2-inch steel to the front end at an angle, so the head could be redirected by rotating the drill string into a specific orientation before pushing forward. I can't say we were the first to do it, but it certainly wasn't common practice. Today's directional drill bits are a much more refined evolution of that same concept.
Founding of Borzall Equipment & Tools
In 1981, I left Melfred, and that's when I started Borzall Equipment. The goal wasn't to build something completely different. It was to improve existing ideas and modernize the manufacturing processes.
We made heavier blades, much larger carbide inserts, and stronger tooling to address the problems contractors kept bringing to us. Every generation solved a new challenge. In the early 1990s, we built a machine with electronics. An operator could stand at a control stand and, using a mixture of hydraulic and electronic power, control the drill rod's forward thrust and rotation with a joystick. Our first directional drilling machine was called the Sure Shot.
In 1991, my son Peter really started hitting the road. We'd go out and do demonstrations, showing contractors how to use the machine and the tooling.
We were really selling HDD as a concept as much as we were selling the tooling and machines we manufactured. At the time, most people had never seen horizontal directional drilling, so every demonstration was an opportunity to show the utility industry how it worked and the tremendous potential it offered for installing underground infrastructure with less disruption. As contractors began to recognize those advantages, the technology started to catch on, and larger companies entered the market with bigger machines.
We didn't have the manufacturing wherewithal to produce tractor-type machines, so we made a pivotal decision to refocus on what we had been doing since day one: tooling. We've been doing that ever since, even though you'll still see remnants of those early drilling machines today. For example, the joystick-type maneuvering tool we developed on the Sure Shot control deck remains the generally accepted steering method used by major rig manufacturers today.
Before the Industry Had a Name
It wasn't until the early 1980s that other companies began to take an interest and mass-manufacture bits and drill rod. At the time, I never thought we were creating an industry. We were simply solving one problem after another. But I did have a feeling that directional drilling had enormous potential. When we were traveling around demonstrating the Sure Shot, I remember the thought that it would not be long before seeing an HDD rig pulled behind a truck would be as common as seeing a backhoe.
Looking back, it is a little like Henry Ford building the Model T without fully realizing what the automobile industry would eventually become. Only years later do you realize you were helping to build an entirely new industry.
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