Cutting data, tools and machining techniques
How to choose the right tool, the right speed, and keep the blade sharp
A machine can be never so precise — the result ultimately depends on whether the tool and cutting data match the material. The regulation on vocational training for machine woodworkers requires that you can independently calculate cutting data and feed rates for optimal machining techniques (§ 4 no. 28) and that you can make the correct choice of tool and processing data for complex tasks (§ 4 no. 25).
§Cutting speed and feed rate
Cutting speed is the speed at which the cut moves through the material and depends on the tool's diameter and revolutions. Feed rate is how quickly the workpiece or tool moves through the material. If cutting speed is too low, the tool grinds and burns the surface; if too high, the cut wears quickly. Too low feed gives the same burning problem, while too high feed gives ragged edges and overloads the tool.
§Tool materials
For woodworking, tools are typically made in high-speed steel (HSS), hard metal (HM/carbide) or diamond (PKD). HSS is cheap and easy to grind but wears quickly, especially in materials with glue and harder fillers. Hard metal maintains sharpness significantly longer and is standard in industrial production. PKD tools (polycrystalline diamond) are used for the most demanding materials — for example particleboards and MDF with high glue content or very abrasive veneered boards — because diamond can withstand many times as much wear as hard metal.
| Tool material | Usually used for |
|---|---|
| High-speed steel (HSS) | Solid wood in smaller series; easy to sand yourself |
| Carbide (HM/carbide) | Standard tools for sheet and solid wood in series production |
| Polycrystalline diamond (PKD) | Very wear-prone materials like chipboard, MDF and laminate in large series |
§Grinding and maintenance of tools
The regulation emphasizes that at both the basic and independent level you must be able to grind, use and maintain tools for manual and mechanical processing in accordance with applicable Danish Standard (§ 4, no. 7 and 27). A dull tool presses more on the material instead of cutting it, which gives a worse surface, more heat development and increased risk of the part slipping from the clamp.
§Cutting data is not a fixed answer list
Cutting data for a given material and tool is often found as recommended values from the tool manufacturer, but the experienced machine carpenter adjusts them based on the machine's stability, the condition of the material and the desired surface finish. The ability to read the result — the sound, the chips and the surface — and adjust accordingly is a major part of the professionalism that the training builds up through the main course.
“The tool tells you all the time whether it is doing well — you just have to learn to listen to the chips.”