Drawknives
Drawknives
EXPERT KNOWLEDGE DRAWKNIVES
Conceptualisation
Drawknives are known by different regional names. These include terms such as draw knives, hoop knives, Wagner hoop knives, cutting knives, cutting blades and draw irons. Got to tools behind these terms is the same. The reason for the multitude of terms is that these knives are used universally in woodworking. In many professions, different terms have been coined depending on the use.
What Shapes of Drawknives are there?
A Drawknives basically only has a 100 - 300 mm long cutting edge that can be guided (pulled) using knob handles. Smaller blade widths are suitable for trimming rungs in furniture making, while the larger Drawknives are used in boat building or for debarking logs.
Drawknives with straight blades:
Drawknives with upward curved blades:
For finishing slightly curved (convex) surfaces or debarking.
Drawknives with downward curved blades:
How do you sharpen Drawknives?
Mirror side / back of the cutting edge (initial sharpening)
- The Drawknives is fixed by hand or clamped with a clamp.
- Firstly, a coarse preliminary sharpening is carried out with a diamond stone or hinged sharpener, e.g. from DMT. It is important to look out for shiny spots during sharpening. These indicate where sharpening has already taken place. Dark spots indicate where the sharpening stones or the hinged sharpener have not yet been in contact with the tool. The front 3 mm up to the cutting edge are crucial for good sharpness.
- The surface is then sharpened with a combination stone and honed. First with the 1000 grit, then with a 3000 or 6000 grit until all scratches have been removed.
If the knife is sharpened again, the mirror side only needs to be honed with a 6000 grit stone. Unless the dark (unsharpened) areas reach the cutting edge.
Bevel grinding
- It is best to guide the sharpening stones or a hinged sharpener from behind (reduced risk of injury) at the appropriate Angle over the bevel. A diagonal guide increases the contact surface and prevents tilting.
- The cutting edge is also sharpened with Grit 1000 and then 3000 or 6000 and honed until all scratches have been removed.
- A burr has now formed on the mirror side, which should be removed using a fine honing stone (3000 or 6000).
Guidance of Drawknives
There are different ways to guide a drawknife. Guiding on the bevelled side (bevel side down) is widely used. Guiding on the mirror side is also possible, but the chip removal is less controllable this way. The movement is always pulling in both cases. The technique for which a bevelling knife is suitable depends on the offset of the handles.
If the knife is guided at an angle to the workpiece, the cutting force is reduced. For fine cuts, the thumbs can be placed on the top of the blade for better control. If you are working on a rip, it is advisable to mark a rip line and make several roughing passes to reach the final depth. The final cut should be made with little Material removal in one continuous pass.
Coloured handles, polished blades?
Some manufacturers, such as Stubai or Kirschen, offer draw knives with coloured handles or highly polished blades. Coloured handles are helpful when enormous quantities of shavings accumulate and the tool is in danger of disappearing under them. However, coloured handles are usually not recommended for Lengthy use from a haptic point of view. Highly polished blades on tools are generally not recommended. In addition to the possibly better appearance, polishing has the advantage that rusting steel is better protected against corrosion. (The finer a surface is polished, the less susceptible it is to corrosion). For most of our Drawknives, this is achieved with a forged skin. The major disadvantage of polished blades are rounded edges on the cutting edge. It takes a great deal of effort to remove indentations on the mirror side, for example, which impair sharpness.
