The lathes Used for machining parts, they constitute a powerful essential tool in the metalworking industry. However, today’s sophisticated lathes have their ancestors in extremely old machines that appeared several centuries before the Christian era and that were intended to work the material available par excellence at that time: the wood.
The wood turning Today it constitutes a vast market that offers a variety of lathes used both in the wood industry and in carpentry, in the manufacture of furniture and wood crafts, and even in the home of a DIY enthusiast. This implies the use of hand tools that must be robust enough to withstand the vibrations produced during turning.
These tools resemble chisels, and are therefore collectively called turner’s chisels. Unlike traditional chisels, turner tools They are hardened and have different shapes, they are provided with ergonomic wooden handles and longer blades for better control and leverage.
Generally, turner’s chisels are manufactured in Carbon Steel, but this material has a tendency to overheat during sharpening and continuous use. The high speed steel chisels (HSS) hold their edge up to six times longer than carbon steel, so the extra expense is worth it in the long run. In fact, most industrial chisels are only available in high speed steel. Some manufacturers also sell cryogenic high speed steel chisels, a treatment that transforms austenite into martensite to produce a steel with good wear resistance properties and a certain ductility, where the useful life of the cutting edge triples that of high speed steel.
As a general rule, it can be established that while not working with abrasive woods, such as teak or elm, for example, carbon steel blades retain their sharpness for a long time. On the other hand, if you work with hard or wet woods, high speed steel tools are the option to follow. In any case, regardless of the material with which they are constructed, the turning chisels must always be kept sharp -a dull tool invites accidents- and for this there are numerous sharpening techniques that the interested party can consult in a timely manner (see videos below).
types of chisels
A priori, we can note that the tools or chisels for turning wood They make up three large families:
gouges: they are half-round shaped steel plates. They have a curved cross-section and are sharp only on the outer edge. They are generally long and require periodic sharpening, which is why their length decreases. There are very different widths or radii, each one for a different function, which we will see below.
Bedans or chisels: they are similar to gouges, but with a rectangular or square body and a beveled finish, which forms an acute angle to attack the wood. They are especially used to make deeper cuts in wood. If it is about handicrafts or for the home, they are usually made by the turner himself from disused square files, but the trade has a wide variety for a wide range of applications.
chisels: These are chisels with wider (4 to 40 mm) and thinner (3 to 4 mm) blades that make shallower cuts than chisels and are mainly used for turning a smooth surface.
Classification of chisels
Depending on your application, chisels for turning wood they can be divided into two basic groups, which in fact can be combined to obtain the desired shape of the piece.
- cutting chisels
- scraping chisels
The cutting chisels are most often used in profiling or turning to the thread or between points, where the grain of the wood is parallel to the axis of rotation of the lathe and include gouges, chisels and reapers or choppers, which are the three most used tools. They are typically sharpened to a razor-like edge when sharpened from both sides. Normally, among others, stair railings, columns and table or chair legs are profiled.
The scraping chisels (usually called scrapers) are generally used in the turning to disk or plate, where the grain of the wood is perpendicular to the axis of rotation. They include universal gouges, chisels and chisels with flat tips, round tips and oblique tips. These are not sharpened on the flat sides, and the wire-like edges left after grinding are left to aid in the scraping process. Examples of plate-turned parts are bowls, glasses, goblets, or plates.
As noted above, there is a multiplicity of chisels for turning wood. Let’s see some.
Roughing or half point gouges: they are always used for the first heavy work on the lathe, that is, turning pieces of quadrangular or octagonal section into cylinders. They are marketed in widths of 18, 25 and 32 mm, their shape is almost flat and they allow wide chips to be started to quickly obtain the first basic shape. They can be used for turning soft and semi-hard woods; the former are turned by holding the tool at a very acute angle, while the latter are turned at almost a right angle. In order to avoid jamming, roughing gouges should not go deep into the wood.
Bowl or casting gouges: they are manufactured with a central milling carried out on the round bar and are somewhat more closed in their inward curvature (between 6 and 18 mm) to prevent them from getting caught in the initial emptying of the bowl. The cutting bevel is elongated and has an angle of about 40º. These deep flute gouges allow for deep cuts when hollowing out. Extra long 18mm gouges are also available for greater control when turning large diameter bowls.
ring gouges: They are designed to prevent the corners of the gouges from sticking into the piece. The circular or ring-shaped blade is an external cut blade with a diameter of 12 or 25 mm.
reapers: Basically, they are designed to cut the parts and remove them from the lathe. Therefore, the blade, normally rectangular in section, although it can also be faceted or elliptical in section, has a rectification that produces an edge parallel to its narrow edges. The most common are:
- Classic or standard mowers: its width varies from 3 to 6 mm.
- Curved cut mowers: These are usually 6mm wide and the blade is ground along a narrow edge to form two cutting points that split the wood open before the cutting tool.
Scraping tools (scrapers)
profiling gouges: they have a round tip, a width of 6 to 25 mm and take the place of the roughing gouge when turning to the plate. They are made from a round bar to which the central groove is milled, although there are also more flattened profiling gouges that are manufactured as roughing gouges. The cutting bevel is longer and has an angle of 30-40º.
Chisels and straight cut chisels: they are used for finishing parts in chuck turning. The width of the blade ranges from 6 to 32 mm.
Oblique cutting chisels: Like the straight cut ones, they can be used to smooth parts in plate turning, although they are also used for molding.
Round tip and convex tip chisels: they are used to work the inside of bowls and cups. The width of the sheet can vary between 12 and 25 mm.
square tip chisels: they are mainly used on the outside of bowls or on the flat bottoms of turned boxes. They are manufactured in the same sizes as the round point and convex point varieties.
Side tip chisels: they are especially useful for working inside any type of hollowed-out utensil. They have an 18mm wide blade.
Diamond-tipped chisels: generally have a pointed edge at an angle of 90 degrees. They are used for making “V” grooves on turntable parts, as well as for cleaning right angle corners. The width of the blade ranges from 6 to 32 mm.
The video that follows, divided into two parts, is a very complete tutorial about the various types of tools for turning wood, as well as their sharpening.