Tools and Stone cutting Version 19.09.2004

Daniel Mettler Laubeggstrasse 6 3013 Bern +41(0)31 332 27 74 +41(0)79 565 68 08 [email protected]

Urs Lippert Mettenbach 4934 Madiswil Switzerland +41(0)62 965 46 26 +41(0)78 621 73 70 [email protected]

© 2004 +41/55/246'34'55 Gerhard Stoll +41/78/761'38'18 Trockenmaurer / Dipl. . ETH/SIA [email protected] Hüeblistrasse 28 www.stonewalls.ch 8636 Wald / Switzerland www.trockensteinmaurer-verband.ch 1. How the type of influ- Working stone we differentiate bedded rock and amorphous rock. The ease of working ences stone cutting and the splitting characteristics differ greatly between bedded and amorphous rock. The grade of bedding determins the to use and the technique to adopt. (cf. fig. 1). A good bedding is caused mostly trough binder/ bondstone a planar inner structure of the rock. Planar textures can originate from diffe- rent geologic prcoesses, however mostly strecher flat and thin stone bed-like jointing, foliated structure or chasms are responsible for it. Important for the working and splitting of stone is that the planar textures are the weak figure 1: spots of the rock. Hence when we have bedded and cyclopic to work stones we should always try to irregular stone cyclopical stone stone forms make use of these defects. We can de- tect this planar texture by noticing diffe- rences in grain size of the mineral constituents, troough a distinct bedded structure or noticable fine joints which point to chasms. Mineral veins are always a certain indication of chasms. Often chasms are so distinct taht the building stones by nature have good building surfaces which barely have to be worked.

When the used rock lacks a planar texture the rock tends to take a cyclopic form. Mostly these are bulky rocks which are characterized trough a uneven structure and a homoge- nous distribution of the constituent minerals. and volcanic rocks for example are rocks which tend to form cyclopical pieces. If chasms are absent is is difficult to cut the- se stones to a bedded form. A further important property is the degree of hardness. Quartzite, hard and other compacted finegrained rocks can be split easily. A further advantage that hard stones tend to be resistant against weathering.

The cleavage property of the rock are as important for the quarrying as it is for the cut- ting of the blocks. Besides the bedding also the arrangement, size and bond between the mineral grains and the humidity play an important role and and influence greatly the splitting characteristics of the stones.

The cleavage property is systematized in

- good (perfect) - good (easy) - distinct - moderate - poor - not cleavable

Thus the following cleaving forms can be distingished:

Training manual dry stone walling www.stonewalls.ch page 2 Tools and stone cutting Stone splits precisely with a flat sur- face All finegrained plutonic rocks, bei plattigen extrustive rocks, most and some sandstones.

figure 2.1:

Stone splits with a slightly undulating surface All finegrained plutonic rocks, some sandstones and schists parallel to the bedding. figure 2.2:

Stone splits with an irregular surface (breaks out) Finegrained vulcanites and magmatites, most and dolomites.

figure 2.3:

Stone doesn't split Porous rocks (lava, volcanic tuff, most conclomerates and some sandstones)

figure 2.4:

Stone breaks up Badly consolidated sedimentary and loose clastic rocks.

figure 2.5:

Stone splits in right angle to the hitting direction Schists of all kind some gneiss rocks when hit against the bedding.

figure 2.6: Training manual dry stone walling www.stonewalls.ch page 3 Tools and stone cutting 2. General considerations for The splitting and cutting of stone requires the use of special tools. Thea differ depending cutting stones on the type of rock to be worked. The cutting and splitting of stone is well described in lit- terature, it mainly treats the trade of the stone mason. The tradition of stone cutting re- aches back to the ancient cultures of and Egypt. It is not easy to draw a border between art and mere craft as it is difficult to designate exactly the tools of the dry stone mason, the tools for the stone dresser. Depending on the demands of the client, techniques and tools choesen for the realization of an building differ.

For traditional dry stone one can say that historically only few tools were used. The indispensable tools consisted of a lump , a sledgehammer and a . , machines and other equipment were only seldom used.

The surfaces which eventually have to be worked are the top and bottom bed, the joints and the face (cf. fig. 3). The art of the dry stone mason consists in the skillful selection and matching of stones with a minimum of cutting. A trained eye, power of spatial imagi- nation and not to forget the experience play an equal important role as all the supporting machinery and tools.

In the following are described the most important techniques and tools for splitting, cut- ting and lifting.

figure 3: terminology

2.1 Technique of stone working When cutting stones the hardness of the rock to work plays an important role. Accordin- gly we choose different tools for the working of soft stones than when we work hard sto- nes. The first step is the choosing of the stone to cut. It is important to judge the stones according to the following criteria:

- visual criteria (color, structure, natural bedding, chasms, clefts, cracks, weak spots). - acoustical criteria: faulty stones sound vague, muted when striked with a hammer.

2.2 Splitting After selection, very big stones can be split with wedges. To do this holes are chiselled out or drilled along the line the stone is to be split. The distance between the holes and the size is dependent on the type of rock to be split. Today in Switzerland the holes are chiselled with a pneumatic hammer or a pneumatic / electrical drill. For stones the size used normally building dry stone the distance between the holes is about 10 - 15 cm and the diameter is normally 22 mm. It is best to pierce the whole stone to avoid a warped splitting surface. The stone is the split using wedges or plugs and feathers

Training manual dry stone walling www.stonewalls.ch page 4 Tools and stone cutting figure 4, left: Drill holes in a distance of 5 - 15 cm.

figure 5, right: A B A, splitting with a wed- ge, and B splitting with plugs and feathers

"Plugs and feathers" are especially handy to split stones. The smallest size to get has a diameter of 22 mm and a lenght of about 10 cm. For the need of the dry stone mason this size is adequate. The three-pieced wedge is inserted in the drilled holes and alterna- tely hit with the lump hammer. It is very importandt to hit the plugs and feathers equally (noticeable trough the sound the plugs emit when hit) to get an even splitting. Splitting stones we differentiate between splitting with or against the bedding (cf. fig. 6 and 7). In most cases more wedges are needed when trying to split against the bedding. To get an even split it is best to pierce the stone fully when drilling holes for the plugs and feathers.

figure 6, left: Splitting of a horizontal bedded rock figure 7, right: Splitting of a vertical bedded rock

Besides drilling and splitting with wedges or plugs and feathers a simpler and time- saving technique can be used. It is mainly used when splitting parallel to the bedding and when shaping big but not too thick stones. It is the splitting with spalling sled- ge and sledgehammer.

When cutting plates at right angles to the bedding one side of the stone is put on a scantling. Then the desired splitting plane is marked with the pointed side of the figure 8.1: spalling sledge on all faces of the stone. Then with ever stronger blows on the mar- ked line the stone is hit until it splits. The sound of the stone emits when hit gives us information about the splitting process.

When splitting parallel to the bedding even large stones can be split up in plates. Doing this it may be handy to work with two big (and two masons): a figure 8.2: Training manual dry stone walling www.stonewalls.ch page 5 Tools and stone cutting spalling sledge and a sledgehammer. The spalling sledge is put on the stone like a pitching . The sledgehammer is used to hit the spalling sledge.

figure 8.3:

figure 9.1, left:

figure 9.2, right:

figure 10.1, left:

figure 10.2, right:

2.3 The cutting When the big blocks are split up the blocks are roughly shaped. At first the protruding points on the bedding faces and the joints are cut off so that the stone fits roughly the neighbouring stones. Once for this rough work mainly sledgehammer and mason's hammer were used. Today we use also chisels, pneumatic and electric machines.

The bedding faces and the joints are then prepared to fit as close as possible the top bed surfaces of the adjacent faces. The sur- face touching the adjacent stones should be as big as possible and lay as near the face as possible. The tools used to do this joint figure 11: are mainly the punc and tracer. schematic sketch (sec- tion view) of the surfa- ces to be worked (hat- bottom bed ched).

Training manual dry stone walling www.stonewalls.ch page 6 Tools and stone cutting Figure 11 shows the surfaces which have to match as closely as possible. Eventually also the face has to be grossly squared off.. The work starts with marking the face plane by hitting the stone from the side with the pitching chisel. The blow is alway directed from outside tn direction of the center of the stone (cf. fig. 12.1). Doing this in the center of the surface there remains a protruding piece of stone which is cut off using the or the tracer (cf. fig. 12.2). Never work the stone from the center towards the margins. Doing this there is a considerable risk that large pieces of the desired surface can break out (cf. fig. 12.3).

figure 12.1, left: --- desired surface --> direction of hit a a figure 12.2, middle: b Chiselling off protruding rest in the center of the desired face figure 12.3, right: a direction of hitting al- ways from outside to a: correct direction of hitting the center! b: wrong direction of hitting

Depending on the expectation of the client a third working step can be added by very fi- nely smoothing the stone surfaces. This could enclose the use of the pointed chisel, tooth chisel or . It is very important to choose the right tools as the charac- teristics of the rock influence the possibilities of smoothing and also sets limits to it (cf. fig. 13 and 14). This fine work is normally not included in the work of the dry stone mason.

figure 13, left: Smoothing of surface- sof granit using the pointed chisel.

figure 14, right: Smoothing of surface- sof granit using the pointed chisel.

2.4 Hitting technique When working stone mind a straight posture. It should be possible to work the stone standing straight in front of it without a twisted body. The room for swinging the hammer should not be obstructed. The security of the mason and of bystanding persons has to be guaranteed (swinging of hammer, flying stone splinters). Don't use excessive force hitting with the hammer. The hand should rather guide the hammer easy to the chisel, letting the work to the dead weight of the hammer. at the moment of the impact the grip around the chisel and hammer should be loosened for a second to avoid the transmissi- on of vibrations and stresses from the chisel and hammer into the hand. The hand should be trained gradually to the weight of the hammer . A begginer should start with a hammer of about 0.8 kg, the limit for continous working is about 1.5 kg.

The chisels are always held at the back end of the chisel. The hand encloses the shaft slightly underneath the plane where the chisel is hit. This way the risk of not hitting the chisel but the hand is minimized (if the chisel is held at the tip, even small movement re- sult in a big movement at the backend). The results of the blows on the chisel (bouncing, slipping, sound, etc.) give us the possibility to adapt the angle of the chisel and the force of the hammer blows.

Consider the following: - The fissure developing runs always along the path where the stone is weakest or the force and tension developed trough the blow is maximized. - The harder the blow the deeper and straighter the penetration of the fissure. Training manual dry stone walling www.stonewalls.ch page 7 Tools and stone cutting 3. Tools For the splitting, cutting and lifting of the stones we distinguish tree families of tools: Hammers, chisels and lifting devices. Often the tools are named differently in different regions. Following are presented the most important tools with the Im Folgenden wer- den die wichtigsten Werkzeuge mit den gebräuchlichsten Namen kurz dargestellt.

3.1 Hammers Even today the hammer in its different expressions is the main of the dry stone mason. Under a great many of different types here the most important in our region.

sledgehammer Two flat ends. The sledgehammer is used to shape the stones very roughly. It weights up to 10 kg. Due to its force it can also be used to figure 15.1 smash stones if rubble and wedges for the back packing are needed.

Spalling sledge One flat end, one pointed edge. The spalling sledge has a distinctive edge which is used to mark an exact splitting line on a stone. Size and weight equal the sledgehammer. The sledgehammer can figure 15.2 be used to hit the spalling hammer.

carpenter's hammer / geologist's ham- mer Used to chip off small pieces of thin sto- nes. The flat end is the main working end of this hammer. The flat faces are often forged in a concave form. figure 15.3

banker mason's hammer Used to work the stones directly without chisels. Can be used like a pitching chisel. The edges of the hammer are sharp and the faces of the hammer have a concave figure 15.4: form. The faces of this hammer are harde- ned. The weight varies between 1 and 3 kg.

lump hammer The lump hammer of ordinary steel is used to hit on the different chisels. Its ed- ges are rounded and the faces are slightly convex. It's weight varies between 1 and 1.5 kg. There are many different types of lump hammers (cf. fig.15.5).

figure 15.5: Training manual dry stone walling www.stonewalls.ch page 8 Tools and stone cutting 3.2 Chisels Beside the hammers chisels made of steel (of different hardness) or chisels with carbide / tungsten insets are used. They are handy to work the edges and surfaces of the buil- ding stones. We diffrentiate between tools for hard stone and tools for soft stones. To cut stone sucessfully the force of the blow and the angle of the chisel is decisive. To hit chi- sels always use hammers of mild steel, never use a hardened masons chisel. A hammer of hardened steel is brittle and there is danger that metal splinters of the hammer can break off and cause serious wounds. For hitting wedges (but not plugs and feathers) a sledge hammer is used.

When building dry stone walls the stones should be worked as little as possible. The art of the dry stone waller is not to work the stone so that it fits the neighbouring stones, but to find with a practised eye the matching stone without working it. Therefore tools should be used only if absolutely necessary. Therefore stone cutting has a supporting function it is a help, that supports the fast and more precise placing of stones (working of bedding faces, closing of joints, bonding of the back packing).

Usually the chisels are used in the following sequence:

- Pitching tool (working of the edges) - Hand point and Hand tracer (rough flattening of surfaces) - Tooth chisels and finer chisels

Pitching tool The pitching tool is a chisel with a broad cutting edge wich is between 3-6 cm wide. It can be bought made of steel or with a carbide / tungsten tip. Using the pitching tool produces a pressure in the stone which chips off edges of the stones. With the pitching tool straight edges can be tra- ced.

figure 16.1:

Steel chisel With the steel chisel all surfaces of the stones can be worked. It mainly serves to figure 16.2: remove fine bumps and unevennesses. Hit with steady blows in a steep angle with the small sledge. Used on all rock types. Has to be reforged and hardened if blunt

Punch / Hand point A chisel which has a strong carbide / tungsten tip. It is used to work the surface of stones roughly. It is used mainly on sto- nes of hard rock. The widht of the tip is 0.3 to 0.8 mm. Has to be grinded if blunt. figure 16.3: Training manual dry stone walling www.stonewalls.ch page 9 Tools and stone cutting Hand tracer The hand tracer has a broad edge which cuts the stone. There are different sizes available.

figure 16.4: Tooth chisel The tooth chisel is used mainly for the fine working of the surfaces of soft stones.

figure 16.5:

Wedges (A), Plugs and feathers (B) Used to split stones by cutting holes in the stone in a straight line and then inserting the wedges. Plugs and feathers can be used when round holes are drilled

A B figure 16.6:

3.3 Lifting tools Crowbar The crowbar is a iron bar which has a flat- tened slightly bent end. The other end is pointed. It is used to lift, push and align heavy and big stones. Working with the crowbar the leverage can be used. The- reby the law: force x (force)lever = weight x (weight)lever. The longer the lever the smaller the force which has to be applied to lift and shift heavy loads.

figure 17.1:

Winch Different kinds of winches serve to lift, push or pull loads.

figure 17.2: Training manual dry stone walling www.stonewalls.ch page 10 Tools and stone cutting Rope pulling machine Thanks to a forceful gear ratio this light- weight and handy pulling machine serves mainly to move big blocks. It can also be used on a tripod or a derrick crane. The The machine can be easily transported and is thus also useful in remote locations.

figure 17.3: Tripod The tripod is normally held together at the top by ropes or a flexible joints. To lift loads a pulley is attached at the top. Tri- pods are mobile and easy to move around. It can be used in remote areas to lift and place heavy stone blocks.

figure 17.4:

Gantry crane

figure 17.5:

Guy derrick

figure 17.6:

crane with two pulleys

figure 17.7: Training manual dry stone walling www.stonewalls.ch page 11 Tools and stone cutting 4. Toolcare How to put a handle to a hammer

For tool handles in Europe normally wood of ash is used. However wood of hickory, maple or false acacias is more enduring. Prior to putting the handle to the tool the wood should be dried down under the average humidity (approx. 15 weight-%). This way the wood swells slightly and sits thus tighter in the tool. While today we normally buy tool handles in a shop they can also be manufactured from scratch. Although this consumes more time this way it is possible to control carefully the grain and texture of the wood. The grain should run undisturbed by faults and branches from top to the end of the handle and not run in an angle to the axis of the handle. In the handle the grain.should run parallel to the longer axis of the oval section. This way the wood can bear better the forces induced trough the blows. Handles with an imperfect grain should not be bought. The top of the handle is filed / rasped down that it fits exactly inside the hole of the hammerhead. The handle can thus wrong correct be introduced with a few blows on the hammerhead. Pay atten- tion that the handle is not weakened below the head by taking off too much material. Af- terwards the handle is spread open with wedges at the top to fix the handle in the ham- mer head. Loose handles should be fixed with hammering in further wedges. A fixation of the handle trough swelling under water is not advisable as the toughness and elastici- ty of wood diminishes greatly when wet.

The handle should not be too long to avo- id force induced stresses in the hand of the mason. To ease the grip it should be slightly tapered and has at the end a dis- tinct thickening. This prevents that a wet or slushy tool glides out of the hand. The Handle housing on both sides conical masons hand is thus relieved and cramps less often.

Handle slightly tape- red to improve grip. figure 14.1, left: End of handle thicke- Sketch of the system ned. hammer - handle

figure 14.2, right: Layout of wedges.

Care of chisels

The pitching tools have to be regularly maintained. Burrs and "mushrooms" at the tool end have to be grinded off, to minimize the danger of injurys through flying off metal- splinters. The carbide / tungsten insets of the tools also have to be grinded regularly to maintain sharp edges and to make an efficient working possible.

Before starting to grind mind the following security principles: Wear eye- and ear protec- tion. Tie up long hairs, keep away loose clothes from the grinding wheel.

To grind off burrs a can be used. The tool is fixed and the angle grinder is guided with the hands. To grind the hard carbide insets one has to use a fixed grinding machine with a suitable wheel (diamond or carbide). When working on such a machine the tool is guided by hand along the grinding wheel.

It is an advantage if the chisel can be supported while being grinded. The chisel is gui- ded with easy small movements over the whole width of the grinding wheel to avoid an irregular use of the grinding wheel. The tool is held against the direction of the turning wheel. It is important to take care that the chisel does not get too hot as it looses it's

Training manual dry stone walling www.stonewalls.ch page 12 Tools and stone cutting hardness when overheating.

Generally it is important to grind off a minimum of material and to maintain the original angles of the surfaces of the chisel.

5. Literature 1 Kündig, R. / Mumenthaler, T. / Eckhardt, P. / Keusen, H.-R. / Schindler, K. / Hof- mann, F. / Vogler, R. / Guntli, P. (1997): Die mineralischen Rohstoffe der Schweiz. Schweizerische Geotechnische Kommission, Zürich.

2 Labhart, T.P. (1993): Geologie der Schweiz. Ott Verlag, Thun.

3 Passchier, C.W. / Trouw, R.A.J. (1996): Microtectonics Springer Verlag, Berlin

4 Reinsch, D. (1991): Natursteinkunde – Eine Einführung für Bauingenieure, Architekten, Denkmalpfleger und Steinmetze. Ferdinand Enke Verlag, Stuttgart.

5 Weber, R. / Hill, D. (2002): Naturstein für Anwender – beurteilen – verkaufen – verlegen. Ebner Verlag, Ulm

6 Baetzner, A. (1991): Natursteinarbeiten im Garten- und Landschaftsbau : Vorkommen der Gesteine, Be- arbeitung und Verwendung. Verlag Eugen Ulmer, Stuttgart.

7 Mehling, G. (Hsg.) (1981): Natursteinlexikon. Verlag Georg D.W. Callwey, München.

8 Obderbecke, A. / Wittenbecher, H. (1912): Der Steinmetz. Verlag von Bernhard Friedrich Voigt, Leipzig.

9 Handwerkskammer Braunschweig (Hsg.) (1994): Steinmetzpraxis. Ebner Verlag Ulm, Ulm.

10 Schweizerischer Baumeisterverband (1946): Richtlinien für die Ausführung von Natursteinmauerwerk.

11 Portmann, B. (2000). Steinbearbeitungen. Verlag Schweizer Baudokumentation, Blauen.

12 Frieder Bernhard (Hrsg). (1996): Der Steinmetz und Steinbildhauer - Band 1, Ausbildung und Praxis - Band 2, Die Arbeit am Stein Callwey, München.

Training manual dry stone walling www.stonewalls.ch page 13 Tools and stone cutting