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8 Impact tools

Hammers

Stones were the first hammers.  Most hammers were selected for practical reasons like a convenient fit in the hand or appropriate hardness.  Generally a harder material is used to work a softer material; otherwise the tool itself might be consumed first.   Archaeologists can distinguish ancient hammer stones from naturally formed pebbles because of where they were discovered and evidence of wear.  Some hammer stones were given spiritual significance. 

 

Flint knapping diagrams Later pre-historic hammerstones

 

Ancient ceremonial jade axes are relatively common.  They were probably valuable from the very beginning because jade is rare, working it is difficult and people cared enough about these objects to carry them great distances from the sources of the stone.  In his book The Mind in the Cave, David Lewis Williams described the round quarts hammer stones used by southwestern Native Americans.  Quarts stones possess triboluminescence, which means that they produce flashes of light in their interiors when rubbed together.  This was particularly effective in dark spaces.  This does not necessarily happen when they are used as hammers, but it is felt, then that strange quality by itself might have been enough to confer spiritual significance onto quartz hammer stones. In some cases pairs of quarts pebbles are still referred to as “lightning stones’ or “lucky stones.”  These are ‘power tools’ of a different sort than the way we use the term today.

Since those first stones were used hammers have evolved into an extraordinary variety of shapes and sizes.  They can be found all around us but in forms as unlike each other as golf clubs are from car pistons.

 

 

 

Most contemporary power tools are versions of what already existed as hand tools amplified by energy coming from another source. The pneumatic, or air hammers are one of the few distinct changes to be introduced as a power tool. Although many power tools are based on rotary motions, air hammers break the pattern by making use of a repeating piston cylinder. The air hammer carves with many tiny blows rather than a few big ones: force is replaced with velocity and quantity.  The air hammer is capable of making very long smooth lines. An air hammer has more in common with the inside of a car engine than it does to the swing of a traditional hand-held hammer. The same principle, but on a more brutal scale, is used by the jack-hammers that break up the pavements on the streets.

 

  

 

A wooden mallet is frequently used in carving soft stone or wood.   Wood will not deform the striking end of a metal tool, as most metal hammers would, and it also softens the force available to drive the cutting edge.  There is also a different ‘spring’.  Plastic mallets made of nylon, polycarbonate, or polystyrene are increasingly used by carvers for similar reasons. 

Beedle mallet, a large wooden mallet with a circular pine head, and rounded edges.  The head is about 18 inches to 15 inches in diameter and its handle about 3 feet (0.91 m) long. It is used by paviours for punning paving stones into position when bedding the stones into a sand base.

Split head mallets have removable faces that can be adapted to whatever is appropriate for the job. These are a kind of hybrid tool, similar to some stone axes, combining the uses of chisel, bush hammer, or stone axe.

The hammers with metal heads come in several forms: the shape of the metal might be rectangular, or curved to mimic the swing of the hammer, or round resembling the wooden mallets (but much smaller because wooden mallets need to be comparatively larger in order to have enough weight.)

The length of the hammer handles varies as well.   Many carving hammers have short handles, keeping the weight and the action well concentrated.  American granite carving handles have long handles that get thinner near the head.  This gives a slight whiplash movement that increases the sharpness of the blow.  Japanese hammers can extend this principle even further as they are fitted with even longer natural twig handles, giving the Japanese hammer its characteristic spring and sharp impact.

 

 

A hammer cannot be made unless another hammer exists, the blacksmith needs one hammer in order to make another one.

Chisels

A chisel is a tool of focus.  It is able to condense the entire force of the blow into a single point.   An un-tempered chisel might actually be softer than the stone. Tempering makes it harder.  If the chisel and the stone have almost the same durability, then the angle and delivery of impact becomes particularly important. Learning what angles to employ in specific situations has been a relevant skill since even before metal tools.

 



The granite carved in Mamallapuram is quite hard in relation to the fire-sharpened chisels that are used there. Constant repair and re-tempering of the chisel is needed.  The blacksmiths are busy nearly the entire time the carvers are working. In the workshop of Dr Ganapati Sthapati one of their sculptured figures will take eight months to complete.  The chisels last only three to five minutes before they need to be re-sharpened.  That means thirty thousand chisels are used on each figure. 

(If a sculpture takes 8 months  (about 250 days), and a chisel lasts 4 minutes then at 15 per hour x 8 hours  = 120 chisels re-sharpened per day x 250 days = 30,000.)

Chisels are sometimes made from whatever steel is available.  Car and truck springs are valuable because they provide good quality steel for chisels.  Chisels have also been made out of rebar, the kind of steel reinforcement meant to be embedded in cast cement.

 

 

 

Inserting tungsten carbide tips into the carving end of the chisels is a practice that has spread throughout carving communities worldwide, though still rare in India in part because of tradition and in part because carbide is so expensive.  Only small pieces of carbide are put in the tips of chisels, in a system not unlike the ancient chisels that attached a hard stone into a shaft of wood or copper.

The pitching tool is a unique and useful chisel. Its cutting surface is angled slightly so that when the tool is held against the stone, the lower edge touches the stone but not the upper part until it is struck with the hammer. It is used for accurately taking off larger chips.  Within the family of chisels it is an effective curiosity.  Lenore Thomas Straus described it this way:  “Even the cutting edge looks wrong.  The quarter-inch thickness of its broad blade is beveled to an angle that seems to contradict its own direction.”

Bushing tools are waffle-shaped chisels that are used perpendicular to the stone.  They essentially bruise the stone into a smooth and more integrated surface.  In feather and splitters the chisels do not actually touch the stone.  These wedges are fitted between little divided ‘coats’ that are inserted into previously prepared holes in the stone.

Axes

In skilled hands the stone axe can do much the same work that can be done by hammer and chisel.  Both methods are apt to show the signatures of both the tool and the ‘handwriting’ of the individual practitioner. 

 

 

The axe can be very effective as a facing tool. It naturally creates short chop marks, that can sometimes result in a broken surface as if each stroke is the residual evidence of a single ‘breath.’  In skilled hands, however, and when necessary these markings can nearly disappear and the surface can look so smooth that they seem to have been planned.  Sometimes a finger is held against the axe head to align it precisely and guide it in delicate work.  The action of an axe tends to be toward the vertical, due to the way it is used.

Axes were used extensively in building of European cathedrals, and then fell out of fashion. The axe is perfect for limestone but is not often used for marble.  As marble gained in prominence, the use of the axe began to decline. Except with granite (as use which is found mostly in the United States) the use of the axe has become rare.  Work on granite with a stone axe leaves no characteristic marks and in a finished stone it is nearly impossible to distinguish from work done with a hammer and chisel.

The stone axe evolved from quarrying axes.  Their use followed the stone.  After the blocks were freed from the earth axes shaped the stones before transport.  The axe was picked up again by the mason when the stones were prepared for construction.  In fact the axe was a regular mason’s tool from before the Romans until long into the middle ages. 

The history of the stone axe is almost invisible despite its widespread use in the past.  Very little mention is made of the stone axe in any literature. Diderot did not illustrate axe work in his famous book even though the tradition was still important at the time he made his compilation.  In recent years the axe is being used more frequently in the restoration of cathedrals largely because Pascal Mychalysin, the chief mason for the restoration of the cathedral in Gloucester is trying to re-introduce its use. Gloucester is part of the Seven Cathedral Trust, a unified effort to help promote knowledgeable restoration and competent craftsmen.

Even when the axe began to fall out of use by European masons it continued to be used in quarrying. We learned from a retired quarryman on Portland Island that until recently the quarry team tried to pair left and right handed workers so that they could stand on opposite sides of the stone and ‘face’ the stone more evenly and quickly.

Most quarrying axes have now been replaced by other methods but on this website there is a film from Japan showing how the axe is used to cut a block of stone out of the rocks matrix. The quarrying axe is also still being used in parts of Turkey.


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