« Automata: engineering for a post-oil world? |Main| Aerial ropeways: automatic cargo transport for a bargain »
Hand-powered devices have been used for millennia. However, during the last quarter of the 19th century a radically improved generation of tools appeared.
You are watching: What type of machine is a hand drill
These tools took advantage of modern mass production machinery and processes (like interchangeable parts) and an increased availability in superior material (metal instead of wood).
One of the outcomes included an array of new drilling machines. These human-powered tools were not only a vast improvement over those that came before them, they also had many advantages in comparison to the power drills that we use today.
A 1922 breast drill (picture credit).
For most of human history, drilling a hole into whatever chosen material required an extensive amount of time and effort. The first crude drilling tool was the awl, a sharp stone, flint, copper or bone point that could be attached to a piece of wood. The awl was pressed against an object and then rotated by hand, much like a present-day screwdriver. An alternative primitive method was the "hand drill" or "shaft drill", where a stick was rotated between the palms. Abrasives such as sand could be used simultaneously to make this drilling method more effective. These were extremely labour-intensive tasks, especially when the material that had to be drilled was hardy, like stone.
In his study of ancient stone-working technology (see sources), Denys Stocks came to the conclusion that even with a bronze drill bit it took up to 5 hours to drill a tiny hole 1 centimetre deep in a hard stone like quartz. Drilling holes into hard stone was commonplace in ancient times, for example in construction work and the making of necklaces and bracelets, so it is not surprising that our forefathers were investigating more efficient drilling methods with fervour.
Strap drills, bow drills and pump drills
The first step toward mechanisation was the "strap drill" (also known as "cord drill" or "thong drill"), which offered an increased rotation speed of the drill bit. The tool consisted of a drill bit attached to a longer wooden shaft, which was rotated by wrapping a cord or leather strap once around it and holding the ends with one"s hands; by pulling in one direction and then the other, the shaft spun and drilled into the material. The top of the shaft rotated freely in a mouthpiece which was held between the user"s teeth to exert more downward pressure. The tool was also used to make fire, which is the reason why it is also known as a "fire drill".
The strap drill was widely used, but was eventually superseded by the "bow drill", which appeared at least 6,000 years ago in Egypt. Based on the cord drill, the difference was that the cord or strap, again wrapped once around the shaft, was tied to a bow. Holding the drill vertically and the bow horizontally, the user then moved the bow backward and forward - much like a cellist - to revolve the shaft (picture on the right, by Rudolf Hommel).
The bow drill possessed two advantages over the strap drill: the shaft could be rotated at a higher speed, and as only one hand was needed to handle the bow, downward pressure could be exerted with the other hand instead of the mouth. Smaller bow drills were also used for dental care. The tool could be made from a few pieces of wood, a piece of string and a drill bit. A later improvement to the bow drill was the pump drill, which appeared in Roman times (picture on the left, source). It is similarly operated, except it functions by means of a downward instead of sideward movement. Sandor Nagyszalancy explains how it works in his book "Tools Rare and Ingenious":
"Pump drills get their name from the way they"re used. Pumping the crossbar up and down causes a string to wind and unwind at the shaft, thus spinning a pointed bit that"s fastened to the end of the shaft back and forth. The thick, rounded section just above the bit serves as a small flywheel to keep the spinning motion going."
Once more, the pump drill offered superior rotating speeds and more downward pressure. All these ancient drills were used in conjunction with a sharp drill point or with the help of abrasives (especially when drilling through stone). Pump and bow drills (which could not work without ropes and knots) are among the most successful tools ever made. Bow drills were still used in the western world at the end of the 19th century by carpenters for drilling small or delicate holes, whilst small pump drills are still sold today as a tool for jewellers.
Bow and thong drills operated by several people
The Chinese were especially keen on the above drilling tools. They relied on bow, pump and thong drills up until the beginning of the twentieth century and never developed any of the drilling tools that will be discussed further below. Rudolf Hommel photographed some of the Chinese drilling devices in his book "China at work". Chinese shipbuilders employed a larger version of the thong drill which was operated by two to three people. It was used for drilling the preliminary holes for the iron spikes which they utilized in ship construction. Henry Chapman Mercer describes the tool in his 1929 book "Ancient Carpenters" Tools":
"To work the apparatus, the thong is twisted around the spindle, whereupon one man holds down the pivot handle, thereby pressing down the drill bit into the wood, while two other man, each grasping the thong by one of its terminal handles, or one man holding a thong-handle in each hand and pulling the thong to and fro, cause the drill to twirl back and forth, as with the common bow drill."
The thong drill. Picture from "China at work" by Rudolf Hommel.
According to some historians, the Egyptians also made use of large bow drills operated by several people to make large holes (and to hollow out spaces) in their pyramids. Bronze hollow tubes of about 11 centimetres in diameter in conjunction with abrasives would have been used as a drill bit ("tube drills" or "core drills"), after which the remaining core is then carefully removed. Even larger holes could have been made by performing several drilling operations right next to each other, in a circular form. The core drill allows for larger holes without sacrificing drilling speed, because much less material has to be reduced to powder.
Denys Stocks conducted real-life experiments to see if this method could work, and succeeded. The results indicate that two drillers were required to push and pull a large bow, while a third person balanced a stone drill-cap on top of the shaft to exert downward pressure. Stocks achieved a drilling speed of 2 centimetres per hour in granite stone, and thinks the ancient Egyptians could have reached speeds of 12 cm per hour.
Whether or not the ancient Egyptians applied this technique remains open to debate, though. Archaeological remains of these tools have never been found, and unlike smaller drilling operations (common bow drills, stone drills to hollow out granite vases) these large-scale operations were only vaguely alluded to in wall paintings.
Augers, gimlets and reamers
Another very important invention from Roman times was the T-shapedauger (and the much smaller gimlet). Basically a long drill bit with a pair of wooden handles for rotating it. The tool looks a like an oversized corkscrew (picture on the left, source). Augers were used to drill large and/or deep holes in wood, for which the bow or pump drill was not very useful. They were applied by shipbuilders, bridgebuilders, millwrights, wheelwrights and the like.
In the Middle Ages augers were sometimes equipped with a breastplate on top for more drilling pressure - the user could rest the entire weight of his body on the pad. However, operating them was a tedious task. The Roman writer Vitruvius noted that the difficulty of the boring increased exponentially with the diameter of the hole. Apart from drilling holes, an auger was also used for "reaming" - enlarging an already existing hole.
The drilling action of the auger is based on the principle of leverage: the longer the handle, the greater the potential of applied force.
Some augers and reamers were huge and had to be operated by several people. One example is the wheelwrights" reamer, which was used to core the hub of a wheel in order to receive a metal bearing.
This was again no easy task, because if the hole was not perfectly straight the wheel would hobble along on the axle. Augers and reamers were essential tools until the end of the 19th century. Eric Sloane describes (and illustrates, on the right) the use of the tool in his 1964 book "A Museum of Early American Tools
"Oddly enough, the experts have not decided just how these reamers were used. But I rigged up a wagon wheel on a wheelwright"s bench, then put a hooked reamer through the hub, which I had weighted with 75 pounds. With two men turning a very long detachable handle it worked nicely. With an ordinary reamer, a man exerts about half its weight downward; this can be bettered with a 75 pound weight plus the 25 pound weight of the tool itself."
Pipe and pump augers
Another spectacular example was the pipe auger (and pipe reamer). These tools were used to bore water pipes from tree trunks. This kind of wooden water pipes was quite common in towns and smaller cities from the 15th to the 17th century, notes Maurice Daumas in "Histoire générale des techniques, tome 2" (illustration below, Maurice Dumas).
Stephen Shepherd, author of the Full Chisel Blog, explains how the pipe auger is operated:
"This type of bit will follow the center of the tree (they selected good straight trunks of the appropriate diameter) so the hole will be centered. What is unusual about this arrangement is the very long shank and the interchangeable bits and reamers. Some pipe auger handles were segmented and lengths could be added as needed. The shanks were slightly longer than the logs being made into water pipes. Twenty feet <6 metres> is not an uncommon length."
"There is a permanent set-up to do the work. Saw bucks or stantions to hold the log and smaller ones to hold the shank of the bit in the proper location. After the pilot hole is bored, the bit is changed out to a reamer to enlarge the hole. In order to facilitate the reaming, a rope is run through the hole and fixed to the hook on the end of the reamer. Now the work gets easy for the fellow twisting the handle as he no longer needs to push the auger, the fellow on the other end pulls the rope (also one with weights), pulling the reamer through the pilot hole enlarging the opening, as the handle is twisted."
Illustration by Stephen Shepherd, Full Chisel Blog.
This took quite some time. In his 1751 "Encyclopédie", Diderot writes that one man could bore a 5 cm diameter hole through 11.6 metres of pipe per day in alder or elm, but only 1.95 metres per day in oak. A similar method was used for boring the barrels of muskets and cannons, and for making wooden water pumps to get water up from wells or chisels.
Continuous versus reciprocating drills
The arrival of the auger did not nullify the bow and pump drills. Each had their advantages and drawbacks because they work in totally different ways. Firstly, with a bow or pump drill, downward pressure is applied by one hand, while with an auger it is applied by two hands. Second, the auger turns slowly in one direction, while the pump and bow drill work by quick reciprocating revolutions in both directions. The auger pares the wood into shavings as it goes down; the pump or bow drill pulverizes the wood into sawdust. The result is that the auger is much better suited to drill large holes, but not useful to make holes in materials other than wood. On the other hand, pump and bow drills will only drill comparatively small holes (with the possible exception of the large Egyptian tools), but can be used for drilling holes in all kinds of materials that need to be pulverized instead of pared: stone, marble or metal, for example.
Medieval breakthrough: the hand brace
While augers remained essential tools for large diameter holes until the end of the 1800s, the Middle Ages brought an important drilling innovation when it came to somewhat smaller holes: the "hand brace" or "bitstock". It introduced - for the first time in history - a continuous
drilling motion. Both bow drills and augers worked by means of intermittent rotations, and during the short pause in between turns the drill bit had the tendency to get stuck.
The U-shaped body of the brace solved this problem. The user turned the handle continuously while exerting downward pressure with the hand or the chest on the pad (some later braces, the cage-head braces, had a larger breastplate). Braces came in many different sizes, with lengths varying from 10 centimetres or less to tools almost half a metre long.
The earliest representation of the hand brace dates from 1425, when it appears on a painting by the Flemish artist Robert Campin. The oldest surviving brace was recovered from an English ship that sank in 1545. Hand braces have remained in use ever since, although they can be difficult to find today. From the 15th to the beginning of the 19th century, braces improved only moderately. Early wooden braces were made with bits permanently attached, while later models had crude mechanisms for interchangeable bits. The shape of the tool hardly changed, but there was an evolution in the materials used.
English hand braces. Source: Hans Brunner Tools.
Most medieval hand braces were made almost entirely out of wood (sometimes even a naturally curved limb of a tree) with some minor iron reinforcements, and - of course - an iron drill bit. Later models were heavily reinforced with metal plates. Some braces were very crude, while others may be considered works of art. The early 19th century "Ultimatum" braces made by William Marples, crafted from japanned ivory or exotic wood (ebony, rosewood) and decorated with engraved and polished brass sidings, were famous for their aesthetic appeal.
Modern hand powered drilling tools
The next revolution in hand powered drilling tools only occured at the end of the 19th century, with the arrival of much improved hand braces and a whole new class of drilling tools: geared drills and boring machines, which took over the heavy duties from augers. They were much more powerful and versatile than their predecessors, but unfortunately their success did not last long. Half a century later they were almost completely superseded by electric power drills. As a result, many people are not even aware of the existence of these remarkable tools.
A rare 1880 combination of hand brace and geared drill, source
In the overview of modern hand powered drilling tools that follows, I will focus almost exclusively on the products of one enterprise: the Millers Falls Company from New York. Although there were a few important competitors, notably Goodell Pratt and North Brothers, Millers Falls dominated the market in the US and their tools are generally regarded as the best. Moreover, since the US became the forerunner of early mass production techniques, these tools became an example for most European manufacturers too.
Cheap steel and interchangeable parts
The improvement of drilling devices was mainly the consequence of the arrival of cheap steel and the invention of interchangeable parts. Randy Roeder, author of a splendid website dedicated to Millers Falls Tools, summarizes the changes in two paragraphs, using the hand brace as an example:
"The braces being offered by American companies at this time were among the finest hand-powered boring devices ever mass produced. The braces of the 1930s would have been a dream come true for a woodworker a century earlier. In the early nineteenth century, most braces were made of wood and prone to breakage if too much torque was applied to them. The forged iron braces sometimes made by blacksmiths were better in this regard, but both types were plagued with mechanisms inadequate to hold a bit securely and incapable adjustment for variations in the size or shape of a shank."
1872 patent premium model lever-type ratchet, source.
"One hundred years later, a brace with an adjustable Barber chuck , mounted on a quality steel frame and fitted with a rotating sweep handle and ball bearing head was considered bottom of the line. Better models came equipped with a ratchet mechanism allowing the user to bore a hole without making a full rotation of the sweep. Some of the best braces were manufactured with all or part of the ratchet mechanism enclosed, or “boxed.” Premium models came equipped with chucks which allowed for bits with a variety of shanks to be used. Fit and finish, of course, played a role in determining the eventual cost of the tool. " Hand and breast drills
Apart from the improvement of the centuries-old hand brace, a whole new range of drilling tools appeared - most notably, so-called geared drills. The earliest picture of a geared drill appears in 1816 and the first geared drill patent is from 1838. It is most likely that they originated in France, perhaps as late as the end of the 1700s. Geared drills finally offered metal workers an alternative to the 6,000 year old bow drill and the 2,000 year old pump drill. WK Fine Tools, a website dedicated to late 19th century drilling tools, explains:
"A geared drill transfers its power from a vertical hand cranked main gear to a horizontal pin gear spinning on a shaft connected to a bit holding device. Depending on the size ratio of main gear to pinion a greater number of revolutions could be achieved from one turn of the crank."
Geared drills (also named "eggbeater drills" - see why) were initially made for drilling in metal, for which higher rotation speeds are a necessity. However, they were also used for drilling into soft wood, in which case the mechanical advantage simply led to easier drilling. Like hand braces, geared drills worked by continuous motion, but they offered the additional benefit of making the drill turn faster than the rate at which the crank is turned. Many models also offered the possibility of changing the bit rotation speed. Geared drills came in two varieties: "hand drills" and "breast drills". Millers Falls Company started mass producing them in 1878 and remained market leader ever since. Randy Roeder explains the differences between the two types:
"Hand drills "Breast drills