- Geared motor, frequency converter, crank and shaft
- The realization
- Fix motor and support bracket
- Drill the basin
- Seal the fitting
- Fix the basin and wire
- Angle grinder or disc grinder
- Support the board
- Power and rotation speed
This potter's trick is the interest of combining high-tech components and elements of recovery, such as a household basin. A real turn... of force, and in the end a equipment which fulfills perfectly its function.
Realization: 1 week-end
Cost: 450 €
Equipment: welding machine, angle grinder, drill press.
See the plan of this realization (in pdf): The potter's wheel: the plan
The potter's wheel is not a complex tool, but it turns slowly and its speed must be regularly adapted. Las, fans who want to build theirs often stumble on the design and manufacture of the system of reduction / variation of speed. Robert Girardin has bypassed the problem using a frequency converter (commonly known as a dimmer).
■ Coupled with a motor-gearbox unit, this converter makes it possible to obtain a speed range from 40 to 150 rpm. If this solution has a cost, such an embodiment remains substantially less expensive than a new tower of equivalent characteristics.
The engine selected has a power of 0.37 kW or 1/2 hp and a speed of 1500 rpm before the gear 1 / 10th. It is supplied with three-phase by the drive, itself powered by single-phase (220 V). The on / off switch and the speed control potentiometer are removed from the housing. They can thus be placed at your fingertips.
■ The turning of the wreath and the tree has been entrusted to a professional. However, you can machine them yourself if you have a metal lathe. The required accuracy is moderate because the speed of rotation is low: the only mechanical complexity is the milling of the keyway. The two parts were welded before machining, but other methods of assembly (pin, thread with locking screw...) are possible. Use stainless steel preferably.
■ The basin, which serves as a collection tray under the handle, is pierced to allow passage to the tree. Four more holes are for TRCC bolts securing the bin to the frame. The shaft is protected by a PVC tube sleeve, glued to the basin with a two-component epoxy putty (stick) that seals.
■ The frame consists of five elements (four feet and one upright) cut into a metal recovery beam and welded together: the back foot is longer to compensate for the weight of the motor. The beam is an IPE of 120, but a UPN would offer the advantage of not having a protruding angle in front of the feet. In addition, the amount would not have to be resized to bolt the motor (fixed by the reducer), as is the case. For those who know how to weld, the manufacture of this base is a breeze.
■ Three sections of perforated angle, bolted to the base, support the electrical controls. Two other angles, made from a drop of aluminum, support the bowl. All elements of the frame are rustproof and two coats of metal paint. For a flawless finish, use a spray paint or work with a spray gun instead of a paintbrush.
Geared motor, frequency converter, crank and shaft
Few elements make up this tour, whose main parts are the 1 / 10th gear motor and the frequency converter. The girelle and the tree were shot by a professional.
Equip your angle grinder with a metal cutting disc and cut to length the five elements of the base. Remove from the upright, the two wings of the beam that hinder the attachment of the engine. Locate the gearbox bolts and angles, point and drill.
■ Chamfer the weld locations on all five pieces. Remember to replace the cutting disc with a grinding disc. It is dangerous to grind with a cutting disc because it reduces its thickness, hence a risk of bursting.
■ Assemble the side feet to the post: point, check the squareness and weld permanently. Grind the welds that would otherwise interfere with subsequent assemblies. Introduce the other two feet, being careful not to reverse them so that the motor is on the right side of the base. Clean and deburr cuts, holes and welds.
■ Extend the support angles of the electrical equipment and the basin. Remove them in order to fix them to the frame with the bolts of the engine block. Assemble the angles to the base. Position the basin, centering it on the output shaft of the gearbox. Locate its fixing holes and drill them.
Fix motor and support bracket
The motor is bolted to the base only on one side of the gearbox. A support bracket of the recovery tank is fixed by the same bolts, the second by two other placed vis-à-vis.
Drill the basin
Cut the PVC sleeve lengthwise and deburr the cut. Drill the basin at its center to the outside diameter of this tube. Use for this a hole saw. If you do not have the desired diameter, drill smaller and then cut the hole back to the cutter. The basin placed on a flat surface, insert the sleeve and place it squarely. Temporarily assemble the assembly with a few drops of cyanoacrylate glue (be careful not to stick the whole thing to the worktop!). Take the necessary amount of mastic and knead to a uniform color paste. Then form the joint between the sleeve and the basin, pressing firmly.
Seal the fitting
In the center of the recovery tank, consisting of a plastic bowl, a sanitary PVC tube sleeve protects the tree. The tightness of the connection is ensured by a bead of two-component epoxy mastic.
Fix the basin and wire
■ Prepare the electrical wiring. From the inverter to the potentiometer and the switch, the cable has two 1 mm2 conductors, to the 1.5 mm2 four-wire motor. As for the mains power supply, it is a standard three-conductor 1.5 mm2 cable. Do not forget to connect the motor ground (or frame) to the ground arriving at the drive.
■ Test the set. If the direction of rotation of the motor does not suit you, do not reverse phases: most converters are equipped with an inverter of the direction of rotation. The majority of them also allow you to program the acceleration and deceleration slope at start and stop. To modify them, consult the instructions that indicate the procedure to follow.
■ Temporarily assemble the lathe for control. Bolt the engine block to the base, without forgetting to place the supports of the basin, and fix it. Install the perforated angles, install the switch and the potentiometer, then wire. Finally insert the handlebar and check the operation of the set again.
■ It is still necessary to disassemble to degrease the metallic elements and to paint them. Apply the antirust (except if the paint incorporates) and then two coats of paint, respecting the drying times recommended by the manufacturer. If you spray or spray, do not forget to cover everything nearby.
■ Position the basin and bolt it. The forced passage of the square collar of the bolts in the round holes of the basin is sufficient in principle to ensure tightness. If necessary, apply silicone or acrylic caulk to the underside of the bolt heads, and thread the wringer.
■ Remount and permanently wire the electrical equipment, then check the operation. Electrical connections are normally out of reach of wet earth spatter. If in doubt, protect them by drowning in a drop of silicone sealant.
Angle grinder or disc grinder
If an angle grinder of Ø 115 mm is a little light to cut profiles of this size, a 125 mm disc model is suitable. It is even recommended for DIY small size, which could easily be driven by a large machine 230 mm in case of sudden recoil.
Support the board
The plate is supported by a tubular axis, which passes through the sleeve and ends in a drilling of the reducer. A key makes it easy to assemble and disassemble.
Power and rotation speed
There are few projections, the speed of rotation being low. In spite of this slowness, the required power is quite important notably because of the pressure of the hands required by the centering.