Postby Gautam Shah


Terracotta soil of the Château de Chambord

Flooring, by virtue of its sheer extent and visual effectuality is the most prominent component of an interior space. Flooring, unlike a wall finish or a ceiling, is a very tactile component. It is used for movement of people and goods, sleeping, resting, bathing, washing, storing, food preparation, and handling and processing of materials.


Floorings provide a horizontal surfaceparallel to the gravity, for conducting tasks, placing facilities, amenities, utilities and other elements. Floors are required to absorb, filter or reflect the sound, air, light, heat, cold, dust, infections, moisture, radiations, etc. Some flooring systems, though play exactly an opposite role, i.e. to allow such elements to selectively pass through.


Like all other interior elements, flooring’s sensual aspects like colour, hue, etc. are of course important, but its tactile aspects like texture, feeling of warmth, cold, hardness or softness, etc., are even more important.



Floorings take-on a very prominent role: in sparsely furnished and lightly occupied rooms and corridors, rooms with high height ceilings, invisible ceilings, unimpressive or non interesting ceilings and in rooms with slopes or levels going upward (allowing larger floor area to be visible), rooms with slopes or levels going downwards (allowing a commanding bird eye view). Floorings sloping away or towards the viewer, do not permit perception of true colours or the visual textures. Floorings, which provide a pleasant experience and enhanced comfort, affect us more.


Floor finish of a flooring system is a tactile and sensorially affective aspect. It can be broadly classified as: hard or resilient, soft or scratch resistant, temporary or permanent, smooth or textured, dark or light coloured, hot or cold, opaque or transparent, absorbent or reflective, etc.



Colour of Flooring affects the spatial qualities of a built space. It primarily determines the level of brightness in a room.

Dark floors cut off bottom up reflection of radiation, and so are ideal in Open to sky spaces like Chowks, on window sills and spaces in front of windows, doors, verandahs. However, dark floors absorb more radiant heat due to the low reflectivity and get very warm. Dark floors are not preferred in walk areas, balconies or on terraces of occupied rooms in tropical climates. A dark floor in water pool heightens the feeling of depth, but can increase the rate of water evaporation due to grater absorption of heat radiation. Very dark and shiny floors show off dust and require frequent cleaning. Dark colours sills in windows increase the radiant heat inside the rooms. Dark sills on cellar windows (or such low natural illumination areas) reduce the level of reflected component of natural light.


Light-coloured floors substantially reduce the heat absorption, provided these are maintained clean. Light-coloured floors provide lightness and enhance the space size. White floors have a natural association with aseptic conditions, so are preferred in food preparation zones, health facilities and in sanctimonious areas (temples). White floors add to the space size or extent.


Coloured floors are used for livening up monotonous or drab spaces (very large halls like departmental stores, plazas, courtyards). Coloured floors are used in industrial plants, schools, hospitals etc. to indicate routes and movement areas for goods, vehicles and people.

City Palace Jaipur India

● Historically Flooring colour has been monochrome where good building stones were available. Earliest exotic colouring elements were mosaics of marble, ceramic and glass. Flooring colours have been exploited in sparsely occupied sections of the building such as corridors, passages, plazas. etc. West Asiatic architecture had monochrome flooring of building stone, and in some cases of terracotta units. Greeks used only white marbles. Greeks used mosaics to create images on the floor. Romans exploited the vast varieties of colourful marbles as inlay pieces, to create borders and central patterns. These pieces of variegated marbles were mainly sourced from debris of old buildings. Byzantine period also reused cut pieces of marbles of Roman columns. Byzantinian only intention was to create contrast and pattern definition, rather than a grand unitary or balanced colour scheme.

Roman use of debris

Herculaneum Floor rhombic tiles

 ● In Gothic architecture the colour through the stained glass window was so strong in the interior space that flooring colour was almost subordinated. However, the quality of laying and finishing were becoming very refined. Granites were used sparingly, only as part of patterns. Where high colour effect was, required floors were covered with carpets, rugs and floor spreads.

Carpet colour swatches

● English mediaeval period saw the use alternatively placed light and dark shades of flooring materials to form diagonal checker board flooring. In Post Gothic period windows’ glass became light hued, interiors were much more illuminated, the interior elements were painted and often gilded. These required a highly polished (glossy- dazzling surface) and a balanced colour scheme with intricate patterning for flooring. Italian business houses, which began commissioning very large buildings had greater daring and allowed large scale use of exotic flooring materials (imported from far-off regions). Renaissance saw painters and sculptors becoming builders and architects, who were very adapt in use of colour. Marbles and stones were selected in terms of not only the colour but their veins or grain patterns. The grain directions were exploited by selection of the cut profile to accentuate the pattern.


● Till 19th century a variety of baked clay materials -terracotta were produced. These had a range of oxide based natural colours of the constituent clays and whites of kaolin. The surface was fragile, porous and difficult to clean. Gazing by salt spraying was very common to make the surfaces impervious. Glazed tiles in variety of colours, ‘slip’ embossed textures, hand-painted and screen-printed patterns, embellishing with glass pieces were produced. For all these the chief fuel was wood, restricting the large scale production. Post 19th C. the Industrial Revolution period there was greater understanding of raw materials and manufacturing processes. The scale of production was very large as the Ceramics began to be produced with mineral coal. Quality was far superior and the range of colours was very large. High pressure casting, continuous kilns and precision cutting equipment helped in perfectly flat and sized flooring products.


● 20th C saw use of graded raw materials, better compaction techniques and controlled vitrification allowing production of highly vitrified flooring slabs that were as good as the natural granite, but with a range of lighter shades including whites.


● Wood Flooring: Wood was a local flooring material for many years. However 14th C Europe imported exotic woods of Asiatic origin, later from African and American locations (North and Latin). Rare woods, appreciated for their wonderful colours, grains and hardness, were used conservatively. The woods were veneered thin to form a surfacing material and backed with boards of low-cost local woods, or used as inlay material.

In 20 th century low-cost wood veneers of extra ordinary thinness were available. These are often grain composed, colour stained, bleached, screen or roll printed and embossed. Laminated flooring units (of paper boards) are replacing the veneer-based wood floors. Low quality wood pieces and chips are re-composed and impregnated with resins to form composite wood floor boards.

wood floor staining

Wood staining with water, oil or solvent soluble dyes is in use for several centuries as a primary and rejuvenating finish for wood floorings. High quality wood staining compounds based on dissoluble dyes helped overcoming the grain and colour equalization problem. Today many proprietary materials such as the melamine, polyurethane, silicone and epoxy-based floor stains are available. Wood bleaching to lighten its colour or of patches has been a craft, used for equalising the colour of wood floorings.

Epoxy coated floors for Industrial workshop




 Post -by Gautam Shah


Windows and Doors, both are penetrable surfaces, but a Door allows intentional physical transition, whereas a Window allows only sensorial connection. Perception through a window is invariably obtrusive. A window as an opening is more manipulable then a door. ‘The eyes are the windows of the soul’, but eyes see what the mind decides to perceive. Khalil Gibran says a window is like a Doctrine -we see the truth through it, but it divides us from truth.


City (1924) by le corbusier Ville le Lac, Corseaux (1924) by Le Corbusier

From a deep interior The view is straight just across it. Everything to the left, right, above and below the window is out of view. Yet, a window allows the taste of reality from the safety of our abode. The safety of indoors, behind a window, is often worth more then being out of doors and free.


In fiction ‘people who look through windows have a narrow view, and are standoffish. These people will watch the world go by from their window, but not do anything about it. People who are scared to look out of the window are people that do not want to know what is going on in the world around them. Even though they are still protected by the glass, they are still worried that the world will be too shocking to behold. Sometimes, these people will open the window just to holler out. These are the ones who believe that they have a say in the world but are not truly a part of’.


The protection of the window instigates us to do things, which one may not dare across a door. We cast off unwanted things out of the window because nothing is likely to bounce back from here. For punishment or revenge people have been thrown out of the windows as an act of defenestration. In some expediencies some enter or jump out of the window like a Romeo. Gaining an entry through a door is much more authoritative then breaking in like a thief through a window. Finestrata in Italian language is slamming shut a window in anger.


Defenestration is an act of throwing someone or something out of a window. The term was coined around the time of an incident in Prague Castle in the year of 1618. The word comes from the Latin de (from; out of) and fenestra (window or opening). Although defenestration can be fatal due to the height of the window, through which a person is thrown, or lacerations from broken glass. The defenestration, though was an act of rejection rather then with the intention of causing death.


The painful experience of going across a window makes one extra ordinarily careful before venturing in or out of a window. Fire or emergency exit doors do not cause as much alarm and skepticism as much as egress windows do. An opening becomes a window due to hindrances it offers, so slight raising of the threshold turns a door into a French window.


It is said heavens have doors only for entry, because no one would want to leave it, ever. Though, heavens have windows to look down and realize the difference between here and there, or perhaps to defenestrate a mischief maker !


Italians try to avoid buttare il denaro (throwing money) out if a window. Mangi la minestra o salti la finestra,’ is the threat an Italian mamma gives to a child who doesn’t want to eat the food she’s prepared. Eat the soup or jump out the window is the Italian equivalent of, Take it or leave it.

Going out of a window could be hazardous, but going out through a door is a conscious move but full of dilemmas. Italian lovers in trouble, however, find a way to uscire dalla porta e rientrare dalla finestra -leave by the door and sneak back in by the window with apologies.

‘A doorway has a narrow view of the world, but a person can walk through the doorway. The doorway is their opportunity to actually make a difference in the world. People who are more willing to make a difference in the world have an easier time walking through the doorway then others. Characters in stories that are too scared to walk through a door are also scared about what the world might do to them. They would rather keep that doorway as their shell from the rest of the world’.


Scaffold Building Manhattan New York City Taxi

Windows, seems to have suggested a different physical and psychological interpretation to J. R. Tolkien. Unlike other openings, one doesn’t usually use a window as a passageway, but rather as a means by which to see and assess the world before using the door to step into it. Because of their relatively smaller size, windows often present a limited view or frame of the world. Tolkien frequently uses this idea to frame a particular character’s view of present circumstances. Virtually every mention of windows includes a reference to light or lack thereof. Because the view through a window is limited, characters may perceive the situation to be better or worse than it actually is, depending upon the perspective the window affords them. In other instances, Tolkien frames the situation for the readers by referring to the level of light seen in a window or by the protective measures applied to the window. Windows generally offer less protection from dangerous intrusion than doors, so their number, size, and treatment reveal the world view of the house’s inhabitants. Hundreds of windows as at Brandy Hall imply a sense of peace, prosperity, and security, as opposed to the heavy-shuttered and curtained windows found in Bree where suspicion and caution rule.’ Crossing the Threshold, Openings and Passageways in J. R. R. Tolkien’s The Hobbit and The Lord of the Rings. By C. Riley Auge.



Post -by Gautam Shah



Colour of the flooring has been a key space defining element. The choice of colour for floorings was once limited to natural colours of the materials that were used. The natural colours of clays, stones, woods, terracottas, ceramics, etc., were further enhanced by the inherent patterns of the materials. The colour scheme was also supplemented by embellishments made of metals, precious stones and glass. The interior floor colours were enhanced by paintings, lighting, rugs, and furnishings. The colour, geometry and bearing of the joints add both the colour and pattern.



Tactile floor for railway platform edge

Patterns in the flooring result from the sizes of materials, geometry of laying, natural colours, grains, textures and constitutional anomalies. Patterns are used as space scaling elements. In large plazas flooring patterns have been used to coordinate, connect and align the surrounding architectural entities of varied sizes, shapes and styles into a cohesive spatial entity. Flooring patterns have also been used to add proportioning elements to a space, create visual linkages between spatial entities, segregate functional modules, mark areas for specific purposes, impose a logical order in a trivial setting, and break the regimen by adding a little frivolity.


Non secular Greek buildings had mosaic floors, with few peripheral bands, but with a large topical central pattern in geometric design or pictorial patterns. For mosaic marble, ceramics, and glass were used. Greeks used white marbles cut to fit the bays of classical column order. Later bands touching the walls were added.

Cosmatesque, or Cosmati, a style of geometric decorative inlay stonework typical of Medieval Italy, Rome and surroundings

Romans used a variety of patterns like: opus spicatum (herring bone), opus sectile (geometric or pictorial), opus quadratum (rectangular blocks), opus incertum (polygonal-crazy), opus reticulum (diagonal effect) and opus mixtum (mix of two materials). Romans used coloured marbles to create inlay patterns. Thermae (bath houses) had perhaps the most garish floorings.

Ostia antica

Romanesque period saw borders of stamped block pattern using same design form repeatedly which later occurred as an interlaced band through meandering or fretting.


Byzantine buildings used bands in walls like in floors. The bands on the walls, flowing over piers, in-fill walls, arches etc. gave an organic feel of continuity, However, the bands on the floor were in basic shapes like square, circle, rectangular. The floor band pattern did not follow the internal architectural configuration at floor level, creating an austere interior.

Aleppo, Umayyad Mosque

Gothic floorings began to move out of the dominance of structural form of the space. Perpendicular space or the verticality was managed by allowing the basic floor pattern to expand into pier widths, side aisles, passages, window offsets, etc. Floors were though heavily occupied by furniture and other demountable structures. Many floor sections were covered with rich embroidered fabrics, rugs etc.


Renaissance buildings were planned by painters and sculptors. Flooring patterns was now a rich visual entity. The flooring patterns instead of being confined within the structural or architectural definitions reverted to strong centralized-theme. However, for the centralized theme figurative or pictorial forms were now not used. Centrality was achieved due to the character of divergence and convergence in the pattern. The space between the central pattern and abutting architectural element was executed in monochrome treatment, enhancing the medallion effect.

Palazzo del Senators, Capitol, Rome, designed by Michelangelo is an oval shaped design with bands defining the pattern character. The floor pattern creates a harmonic visual relationship between buildings of different characters, sizes and functions.

Grand Trianon, Fontainebleau and Galerie des Versailles, have chequered flooring to implicate a scale in a long space. Dual coloured diagonal chequered patterns have been extensively used in Medieval and Renaissance buildings. The chequered patterns have been often bounded by bands. Straight and diagonal chequered floors with corner inlay stones have also been popular as in-filling in pattern. Such floor configurations require multiple bands to define and limit the pattern extent.




Postby Gautam Shah 

Organizations receive and generate lots of data, which have TWO sets of relevance. Information with distant use is strategic, and will be used for planning and forecasting. Strategic information is more general than any tactical information. Information with immediate use is tactical, and is used for decision making and problem solving. Operational uses of information are very occasion or situation-specific.


Information has FIVE qualities:

Brevity (specific to the context),

Accuracy (of the right context or sensible),

Timeliness or up to date,

Purposiveness (capable of causing desired actions),

Rarity (original, novel).


For organizations prime Internal Information Resources (IIR) are: experience and knowledge that comes with owners, employees, consultants, etc., and data generated from the routine activities. For organizations External information resources (EIR) are: media based such as books, periodicals, internet, CDs, tapes, etc., and input and feedback from consultants, suppliers, contractors and clients. These resources once procured by the organization, and if properly stored, can be a great internal asset.


External information is inter-organizational, fraternity level, society, community, national, or of a universal domain. External information is acquired for a payment of compensation in proportion to its quality, quantity and acuteness of need. Organizations, as a result, end up paying a stiff price for sourcing external information.


Internal information is personal, departmental or organizational. Internal information resources are nearly free, require only processing at a negligible cost, but are ignored. Organizations thrive and proliferate on the quality and quantity of data within their reach. Organizations by continuously processing their data generate synergies that in turn sharpen their data processing capacity.


Cost of information: Information as a commodity can have an ordinary cost, if it is universally available and not urgently needed. However, information of rare or proprietary nature and that requiring immediate access can have a high price. Information is also available in many free domains without any obligations. Cost of information is also formed by absolute factors like the cost of acquisition, processing, storing, retrieval and transmission.




 Post -by Gautam Shah




Old buildings often have so well preserved structures, that the shell continues to be valuable as a place of inhabitation or occupation. With some changes such buildings can be made suitable for new uses. Conversion of buildings for new functions becomes easier when such buildings do not carry emotional or other symbolic values. There is no obsession to trace the antiquity and restore the past image of such buildings. As a result, owners, designers and builders, have unbounded scope, for affecting changes in such buildings.

Repurposed space Annes Theatre Under Brooklyn Bridge NYC

Reformations and Conversions exploit the current assets of the building. Reformation of a building can happen, if only the surroundings can support the new occupation. A building is considered fit for reformation, when it represents a saving of physical resources and time, compared to the cost and time required in putting up a fresh building of equivalent size.


Selection of functions or activities, to be established is primarily determined by the

1 – Location advantage the building offers,

2 – Spatial characteristics of the structure,

3 – Empathy its external form now presents or will create after the processes of reformation,

4 – Structural qualities such as equilibrium – stability and longevity of the building.


Commercial activities that exclusively offer economic viability due to the technical functioning of the building, such as the departmental stores, multi storey parks, industrial plants, etc. generally require modern structures. Whereas other occupational activities that provide economic or other levels of validity, from the nature of allowable activities (happenings) rather than the core or programmed functions can be accommodated in reformed or converted building.



Reformations are achieved through processes like Alterations, Extension, Renovation etc. of the building. Expectations for the ‘post reformation’ results are often very basic and without any preconceptions yet of of unprecedented nature. Success of reformation is measured in either the immediate economic gain like rent, or appreciation in the value of the building.


Notions of conversion as opposed to new construction, depends on the scale at which it is viewed. To the city planner the pulling down of a block and the construction of a new one to replace it is a conversion of the city locality, but for the architect it is just a project. For the interior designer furnishing a space in an old building is a new job. Conversion designers operate between two extremes, one within the realm of social relevance and acceptability, and other of utter professionalism to create an entity. Reformations or Conversions rehabilitate buildings. The rehabilitation of a building is very perplexing, Is one trying to re-establish the original functions into a structure that has become dysfunctional, due to structural reasons, malfunctioning of important utilities, or been abused by the social or political upheaval, Or, Is one trying to achieve the functional modifications to sustain viability, acceptability in the changed circumstances?


In Europe many old factories and shore front buildings like warehouses have been reformed. Old palaces have been rehabilitated into resorts. Churches converted into temples of other faith.



IRON or STEEL -technologies through history

Post —by Gautam Shah



       Iron or Steel is one of the most complex of all metals used by man. In spite of its very large volume of use, it still remains a very enigmatic material.


2   Iron changes the properties during manufacture, post processing, aging and usage. Many of the changes are known to man for years, but ignored. Some of these effects became apparent very late in the life span of the structure, or functional entities. Such realizations, though late have not affected us very severely, because superior technologies of later dates provided better guaranteed and efficient solutions.


       Many of the Industrial revolution period steel structures, such as large span buildings, bridges and ships were formed of very inferior materials and fastening techniques (hind sight realizations). But ‘change solutions’ that became available 30 / 50 years later were better enough to have no regrets for replacement. In few cases there have been losses of life, such as Titanic or Liberty series of ships. The only regrets were that often such structures collapsed suddenly.


4        The technological deficiencies that affected the structures and entities were due to ignorance and lack of inadequate knowledge, but similar problems have continued even today due to insincere applications.



5       However, birth of steel fabrication was with cast shapes like parts of columns, capitals, brackets and sections of arches. These were components of compression. Tensile capacity was untested. Hollowed out brackets and arch forming sections had few subsections that were tensile stressed. Tensile behaviour of steel was not completely unknown quality. As the integrity of castings improved, through constitution and methods of cooling, the tensile reliability increased.


6        One of the most widely used form of ferrous metal has been the sheets. Sheets are re-rolled, cut into strips and folded or formed into various sections.


7        Compared to cast steels, drawn steels had better grain alignment and tensile strength was known. Mild steels produced through use of Bessemer process provided the much needed ductility and tensile stress capacity.


       Steels were re-rolled into sheets, but in the manufacturing number of annealing, tempering, hardening processes were perfected.

9        Annealing and Hardening, are nominally considered two extreme processes, former a softening and the later its opposite method. But Tempering that is readjusting the quality of steel is now considered even more important. It is chiefly used in forming various sections, automobile bodies and cages for white-goods. Companies producing furniture, automobiles and white-goods have a selfish interest in replacement markets, and so design their product for 10 years life cycle. After that no one is bothered about the product.




Postby Gautam Shah


Drilling is a very old craft practised by various civilizations. Historically materials like shell, ivory, antler, bones, tooth and baked ceramics, have been pierced through to make adornments. Means and methods for drilling of hard materials like stones, glasses, metals, nodules and beads were developed by ancient people. Soft materials like skins (hides, leather) were punched for stitching or tying.


Deep-set teeth like wisdom (third molar) of live patients were drilled during 7000 and 5500 BC. Skulls with signs of trepanation have been found in prehistoric human remains from Neolithic times onward. Trepanning, (trephination, trephining) or making a burr hole is probably the oldest surgical procedure, dating 40,000 years. It is a surgical intervention in which a hole is drilled or scraped into the human skull to cure epileptic seizures, migraines, and mental disorders. It was also done to remove shattered bits of bone from a fractured skull and clean out the blood that often pools under the skull after a head injury.


Drills have been used for producing new holes, enlarging existing holes and also for shaping cavities to various forms of sections. Drills with special attachments are also used for creating threads inside cylindrical forms. Shallow depth drilling has been used for etching, engraving and carving on very hard surfaces like obsidian and for material removing and surface polishing.


About 110,000 years back Neanderthal man began to use many different types of handled tools like axes, borers, knives and spears. In all these tools, the edges were heavily notched (due to chipping of the stone) but a toothed edge helped in carving, cutting and boring processes for materials like horn, bone, skins, wood, stones, etc. Wood, natural fibres and bones complimented the edge stones for handling and gripping. Approximately 35 000 years back, Cro-Magnon man devised newer tools. Burin, an engraving tool, was made from a sharp narrow flint blade, for incising and burrowing. This made it possible to work the horn and bone into combs, needles, beads and such other small items. Tools similar to a burin were used for cleaning and shaving hides.

Flint blades slimmed to a sharp point were used for piercing holes. Another method could have been to grind a hole with abrasive sand under the point of a stick. Diamond points (‘jeweled’) were used as drilling bits.

The Egyptians invented the circular trephine, made by of a tube with serrated borders (similar to the country tool used for punching a large size hole in masonry structure). It gives a round disk like cut called ‘crown’. The crown cut was worn by the patient to ward off evil.


An awl and the needle were the first hole making tools. These create a hole by shifting or compressing the material to sides rather than removing it. Small, shallow holes in stone, concrete, brick, and similar materials are usually drilled by a hand star punch, (a steel rod with an X-shaped cutting point, which was held against the object to be holed and struck with a hammer or sledge while revolving slightly after each stroke). A hardened metal punch is used even today to push a hole in fragile materials like plaster, bricks. Paper leather, etc. Punch is also used to mark a small indentation, so that drilling bit has a homing mark. Metal sheets cannot be drilled properly so are holed by a pointed punch or a punching die.




The bow drill is an ancient form of drilling tools. It was commonly used to make fire, and was also called a fire drill. However, the same principle also was used widely in drilling for wood and teeth. Bow drills were used since 4th C. BC to drill holes into lapis lazuli and cornelian.




Augers are large size hole making tools. Initially in the Iron Age it was a simple cutting bar or plate joined at a right angle to an axle which could be rotated. Later it was like a short length split pipe. The auger was used for boring softer materials. It removed large quantity of material due to its wide size capacity, so had to be taken out to remove the cut material. Middle age Augers with spiral or helical flutes helped the evacuation of the cut material to the surface. Augurs are now used for pile foundation boring work, tree planting etc.


Chinese, 2,250 years ago, used Augur based drilling device to drill shallow wells to tap brine aquifers for salt production. The rig was constructed from bamboos. The pile pipe with drill bit was allowed to drop by about one mt pulverizing the rock. By the beginning of the 3rd C. AD. wells were drilled up to 140 mts depth. In 1835 the Shanghai well was the first in the world to exceed a depth of 1000 mts in comparison, the deepest wells in the USA were about 500 mts deep.


The other hand boring tools include the brace, a crank shaped device that can be held by one hand and rotated by another (action similar to car lifting jack), the push drill has a spiral flute along which a trunk moves down creating rotations but bounces back, on release of the compressed spring.


The rotary hammer drill (masonry drill) combines a primary dedicated hammer mechanism with a separate rotation mechanism, and is used for more substantial material such as masonry or concrete.


Table or platform drills are used in workshops for cutting holes in wood, metal, rock, or other hard materials. Table mounting is required where jobs are heavy, repetitive and precise. Platform mounting is used for simultaneous or multi drill operations. Tools for drilling holes in wood are commonly known as bits. A number of special forms of bits are also employed, including the expanding bit, which has a central guide screw and a radial cutting arm that can be adjusted to widen already drilled holes. For drilling metal, twist drills rotated by motor-drives are employed.


Chucks are holding devices to drills of various sizes. Rock drills are hammered by pneumatic devices for creating holes to place explosive charges in mining and quarrying. A rotary drill consists of a single auger-like bit, or three inclined positioned circular sets of multiple bits moved by a toothed gear, and the gear rotated by a series of connected steel pipes. Rotary drills are used in drilling oil wells.

Taipei_MRT_Xinyi_Line_Tunnel_boring_machine (2)

Drilling and Boring Machines: Motorized drill machines not only drill new holes, and alter the existing holes by boring or reaming to enlarge it, cut screw threads by tapping it, or lap or hone a hole for accurate sizing (tolerances) and to provide a smooth finish. Drilling machines vary in size and function, ranging from portable to very large radial drilling machines, multi-spindle units, automats or automatic production machines, and deep-hole-drilling machines.


Routers are machines with drilling spindles that move sideways to cut shallow to deep grooves with square or rounded sections to create engraved patterns in materials like wood, plastics and metals. Drilling machines are also operated with pressurized gas -pneumatically, to achieve very high speeds.

Common drills have a single cutting tip of steel made of hardened, carbon steel or tipped with cemented carbide or diamond. A carpenter’s hand held wooden drill takes forward and backward motion from the thong or bow-thread. The dual movement helps in drilling as well as evacuation of dust. Dual movement require double edged drilling bit, compared to a single direction movement bit, which are easy to make and re-sharpen. Drilling bits with spirally fluted columns came into practice much later, in 19th C.


Drilling is done with a small diameter-axial movement so requires high speed and low torque. Drilling removes very little material per rotation. Boring is done with a large diameter so requires low speed but high torque. For finishing large bores grinding wheels are used. Grinding-wheel cutters have a planetary motion, rotating rapidly on their own axes, which in turn rotates on the internal face of the bore.