20 Nisan 2015 Pazartesi

Functions of the Hand Drill

Hand Drills are able to drill the wooden or soft grounds by turning the main handle in any direction. While turning the main handle, a pressure is given by the person to the back of to drill the ground efficiently. To improve the drilling efficiency, hand drills have some mechanized gear setup to increase chuck's turning speed. This setup allows the drill penetration become more easy for the user of the drill.

DRAWINGS OF COMPONENTS

BACK PIN

BOLT1

BOLT2

BOLT3

CHUCK

GEAR1

GEAR2

GEAR3

MAIN HANDLE

MAIN BODY

PIN1

PIN2

PIN3

BOLT UNION

BACK







COMPONENTS OF THE HAND DRILL


BACK PIN
Connects the Back and Main Body

BOLT1



Component to unite parts.

BOLT2


Component to unite parts.

BOLT3

Component to unite parts.

CHUCK

Place to connect the drill.

GEAR1

Component for the function of drilling.

GEAR2

Component for the function of drilling.

GEAR3

Component for the function of drilling.

MAIN HANDLE

Component to hold the device.

MAIN BODY

Component that holds the entire parts.

PIN1

Component of connecting gears.

PIN2

Component of connecting gears.

PIN3

Component of connecting gears.

BOLT UNION


Component to plug the bolts.

BACK
Component to pressurize the drill.

6 Mart 2015 Cuma

What Is a Hand Drill?

A hand drill is a manual tool that converts and amplifies circular motion of the crank into circular motion of a drill chuck. Though it has been replaced in most applications by power drills, the hand drill is used by many woodworkers.

The hand drill consists of a cranking handle that turns pinion gears on the main shaft. A chuck at the end of the shaft holds a drill bit. The opposite end of the shaft has a second handle that is held stationary while the chuck turns. 
How to Safely Use a Hand Drill?
To safely use a hand drill, loosen the chuck and insert the appropriate drill bit, then tighten the chuck. Most hand drills require a special tool to firmly tighten the chuck. Place the bit's tip where you want to cut a hole, making sure the bit is at the same angle as the desired hole. Turn the cranking handle to rotate the bit and drill the hole. With smaller drill bits, be careful not to apply excess pressure on the handle or the bit may bend or break.

How to Maintain a Hand Drill?
Hand drills require little maintenance, but can be damaged by improper use, such as using the wrong drill bit or placing excess pressure on the tool. For optimum efficiency, periodically place a drop of light oil on the crank pinions and in the chuck gear.


History of Drills


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.

Bow 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.

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.

Hand 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 1700’s. Geared drills finally offered metal workers an alternative to the 6,000 year old bow drills 

Geared drills 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.