STONE CUTTING CIRCULAR SAW

Mother Russia is rich in earthly gifts. Among them not last place is occupied by precious, semiprecious and ornamental stones. One Ural! It is therefore not surprising that in Russia, many artists and fans involved in the processing of ornamental stones. And in order to do this successfully, little one desires and abilities – you need a special tool and at least a minimum of equipment; diamond circular saws and accessories for cutting ceramic tiles. However, there are two “but”. First, their application area is quite limited (e.g. diamond discs have a thickness of 2 mm or more, in many cases for cutting ornamental stones are not acceptable). Secondly, their value, to put it mildly, inadequate to the modest income of the average working Russians, especially pensioners.

 

So when I became interested in crafts from natural stone, then, with this in mind, the first thing I decided to design and manufacture small sawing stanochek. The result is a stone cutting circular saw (PCC), is quite simple to manufacture, convenient and efficient in operation.

 

The working principle of PCC is very simple (Fig.1). In a cuvette, the cooling liquid is added with abrasive powder such as silicon carbide. During rotation of the cutting disc captures the abrasive and the contacting of the sawn stone is fixed to the caliper PCC, scratches holes groove that deepens with every turn, until the stone split in half. Use as a working tool-free abrasive is, for example, diamond wheels has some undeniable advantages. First of all, it cost much less, and this, as indicated above, is of great importance. In addition, it is possible to use cutting discs of almost any required size. And it also will not require high costs, since the disks (and they of roofing iron) you can easily make yourself. But keep in mind the one drawback: the performance of free-cutting abrasive is much lower than the diamond circle.

Structurally, PCC consists of two main units: work unit (Fig.S) and power unit located at a distance from the first (this is done to improve electrical safety at work). The drive (Fig.4) used a DC motor on 12V from the fan of the radiator of the car.

 

 

Fig. 1. Design scheme of stone cutting circular saws

 

 

Fig. 2. A circuit diagram of the power supply

 

 

 

 

 

The motor housing has undergone a small revision: I removed two of the three regular fasteners. The motor is placed in the clamp: galvanized sheet metal and with a loop on its end and swivel studs M6 is set to the angle-brackets at the base. On the motor shaft drive pulley is screwed and fixed with a pin with a diameter of 2 mm. On the working spindle, the rotation is transmitted to the wedge-belt (alternator drive belt of the car “Lada”), To tension the belt case of the engine through the remaining fixing element is connected to the earring. Near the engine on the basis of the mounted brass terminals for connection and control buttons in a special housing. Buttons — from an old tube TV (and it is better to use a conventional toggle-type TV-1-1).

 

The base housing (bottom, support, front, side and rear walls) are made of birch planks with a thickness of 20 mm (Fig.5). Walls are connected in a tongue and taped to the bottom. For reliability elements are additionally fastened with screws. After Assembly, the housing is impregnated with hot linseed oil and painted with oil paint.

 

Further, the base is inserted into a 5-liter plastic bottle from under water in the front wall at the place cut a groove under her neck. Then the bottle is cut along the height of the sides of the base. Received ditch around the perimeter nailed to the walls of the base with small nails. Under the neck of the cuvette to the front wall is attached to the gutter of galvanized sheet, 0.8 mm thick, and the top latches set cover. Upper ends of the side walls close reflective strips 30 mm wide, cut from plastic bottles. The strips are fixed with a slouchy fit inside the base with small nails. They serve as protection gaps and joints between the walls and base of the cell from the ingress of coolant with abrasive at the work of the PCC. In addition to these details on the base are mounted earring for fastening the engine at the belt tension, the Central reflector and supports the caliper.

 

 

 

 

 

 

 

 

 

After that, proceed to the Assembly and installation of the work spindle (Fig.8). First of all, define the position of the shaft. To do this, fasten the engine on the earring, as shown in figure 3, the driving and driven pulleys put on the belt and pulled it on, slipping the clutch pulley in the direction of the rear wall of the base. Fixing the pulley, through the hole in the hub spaced on the side wall of the base center hole for the spindle shaft. Transfer the mark on the opposite wall and serverlevel in the side walls of holes of diameter 11 — 12 mm. are Then fixed on the end of the shaft, the driven pulley put on the shaft of one plate — bearing, skip it through the right wall of the base, put on two more flow through the left wall. On the free end of the shaft, put on the last fourth of the plate and consistently secure all of them, providing an easy drive belt tension and free rotation of the shaft. Then take out the shaft from the base, fill the holes in the side walls of the grease type tsiatim-201, and returning the shaft in place, consistently strung on it the washer, the bushing fixed thereto with the cutting disc and the spring. In conclusion, fix the bushing on the shaft lock screw.

Caliper (Fig.3,9) serves for fixing of the cut stone and carry out its feeding to the cutting circle. The stone is clamped between the plate and two straps, are made of Micarta sheet thickness of 6 mm. In the plate between the bars of propylene in the groove for the exit of the cutting circle, and the end drilled a 2-mm hole, which serves for fixing the thread and hanging of the load, if necessary, increase the clamping of the workpiece to the tool. The thread passes through the neck of the flask and then through a chute. Install the caliper is not difficult and clear from the presented figures. The main objective in this case — with a lock M5 screw to fix the plate so that the cutting circle was at the axis of the slit.

 

Cover (Fig. 10) consists of a wooden U-shaped frame, composed of birch sticks, the closing bracket of the 3-mm wire and the body (half of a plastic 5-litre bottles — the remainder of the cuvette). The base cover is attached a small card with a loop.

 

Work on the PCC is as follows. First, in the cell of the base is filled with coolant — water mix with engine oil in the ratio of about 15:1.

 

 

 

 

 

The amount of coolant should be such that the cutting disc was immersed in it for 8 — 10 mm. Further into the cell near the cutting disc from the gutters poured the powder abrasive in the amount of 30 — 40 g. the Powder can be obtained from the end-of the grinding wheel, silicon carbide (green). After fixing the workpiece on the support he gets down on the cutting disc, cover PCC is closed and the motor is activated. After 1 — 2 minutes, you should see the characteristic “rustling”, which means that the cut-off wheel abrasive enters and begins the process of cutting stone. In the first minutes, when the resistance to rotation of the tool is small, on the power supply switch is set to voltage about 6 — 8 V. This helps to reduce engine speed and reduce flushing with abrasive cut-off wheel. Increasing shed supplied to the engine, the voltage should gradually increase.

 

As can be seen from figures 3 and 5, the support base have different heights: front (gutter) of 20 mm, rear 50 mm. This is done in order that the abrasive powder is discharged to the rear, “trickled” back to the cutting disc. If necessary, the PCC it is possible to firmly secure the clamp to the desktop — it is the bottom base made of 12 mm wider than the side walls.

After work, the coolant is discharged through the chute, the grit is removed from the cell (for future use), the cuvette is rinsed with warm water and dried.

 

Power supply (schematic circuit diagram shown in Fig.2) has a standard device. As the transformer used is a modified TS-180 (from an old tube TV). Secondary windings on its coils replaced by a new wound copper insulated wire 2.5 mm2 (see table).

 

The SA1 switch — type PGK-1-11; signal lamp HL1 — 12 V, 90 mA; the capacitor C1 — a type of BMT-2, C2 — C50-6; switch type TP1-2. Diodes VD1 — VD4 (D242) are mounted on an aluminum plate 5 mm thick with dimensions of 80×100 mm and isolated from her mica washers. The installation is made by wire BPVL with 1.5 mm2. The power supply is covered by a cover (of roofing iron) size 190x140x120 mm.

 

In case of difficulties in the manufacture of PCC power pack can be powered from any DC source voltage of 12 V, for example from a car battery or charger to it.

 

The number of turns and voltage across the secondary windings

 

 

 

Technical data of PCC

 

 

STEPANOV, Istra