|Operations on Wood Turning Lathes - Course: Mechanical woodworking techniques. Trainees' handbook of lessons (Institut für Berufliche Entwicklung, 19 p.)|
Turning out variously shaped workpieces makes necessary the processing of materials in different grain directions and in varying profiles. Commensurately, a number of special tools are required. The faces, edges and angles of the turning tool are presented in Figure 10.
Figure 10 - Faces, edges and angles of turning tools
1 main cutter, 2 comer, 3 chipping face, 4 flank, 5 taper angle, 6 trail cutter
The basic equipment of a wood turning lathe includes the following items:
These tubes are used for long trunk and cross piece operations. Basically we differentiate between two types, roughing and forming tools. The roughing tool is used for preturning a cornered workpiece. It has a wide and flat shape. The cutter is straight and has lightly rounded comers. The taper angle of the cutter is, as applies to all turning tools, ground in line with wood hardness.
Figure 11 - Roughing tool
The forming tool is used to turn all rounded shapes of the workpiece. It is mainly used for long trunk operations. Tools of differing widths are employed for various workpiece shapes. As opposed to the jack tube, the cross-section of the form tube is not uniform. As a result varying angles arise at differing tool cutter points during chip removal. This feature exerts a positive influence on handling the tool when turning chamfers and curves. The cutter is ground slightly curved and the comers are somewhat rounded.
Figure 12 - Forming tool
(1) wide forming tool, (2) narrow forming tool, (3) forming tools ground for soft wood processing
A planer is used exclusively for long trunk turning. Because of its shape it is also known as a square-nosed tool.
Figure 13 - Planer
(1) double edge ground planer
1 burr, 2 tip
(2) single edge ground planer with rounded burr
1 burr, 2 tip
The blunt-angled comer of the cutter, the burr, is for turning small curves. The burr can easily be round-ground. The sharp comer can be used for turning notches.
Tubes and planers are the main rool types for manual turning. Whereas the tubes (also called wood planers) are used for long trunk and cross piece work, the planer is only employed for long trunk operations.
This finishing tool is used for smoothing and facing the cross pieces of disk-shaped workpieces. The finishing tool is only ground on one side. This tool is not really suitable for form turning. Chip removal is mainly through scraping whilst the taper angle must be selected in accordance with the material. A very unclean top surface results when this tool is used for long trunk operations.
Figure 14 - Finishing tool
The steel section is very similar to the finishing tool. It is somewhat smaller and, through the addition of various profiles, can be prepared for special tasks.
Figure 15 - Steel sections (various forms)
This tool is solely for cutting long trunk turned parts. The cross-section form must resemble a knife or sword. Its advantage is that the wood grain surfaces are cut cleanly and wood losses are kept down to a minimum. It is difficult to rework the workpiece on these surfaces. When grinding the tool, heed the clearance angle adjacent cutters.
Figure 16 - Cutting tool
1 main cutter, 2 trail cutter, 3 clearance angle
Which tools are used for
What is the purpose of the cutting