Wood Turning - Choose your weapons - Part 2

Tools Tungsten Carbide shafts and Tips (Inserts) for Woodturning

In this second article in a two part series on wood turning tools we are going to look at tools that use tungsten carbide inserts.

During the past 10 years there has been a proliferation in development and the use of carbide tools for wood turning. Generally these are classified as scrapers as the flat sharpened edge of the tip is held at 90° to the grain of the wood.

Fig. 1: Blackline Carbide Moly 4 - Piece Set

Fig. 2: Creative Turning carbide-tipped turning tools.

Carbide insert shapes and sizes

Various inserts are available in four shapes round, square, curved triangular and diamond, and are also available in mini, medium and large sizes.

Fig. 3: Square, round, diamond and V-shaped carbide inserts

• The cutting edge of the Square, Round and W ( diamond shape) can be used in two positions. In the standard position (Horizontal) it is suitable for rough preparatory work, and in the second shearing position is used for finishing with a very clean cutting result. when indexed or rotated by 45 °.

Fig. 4: The rake of the carbide insert is clearly illustrated in this photograph.

• The round cutting edge is particularly suitable for curved shapes, such as bowls on the inside and outside as well as rounded flutes.
• The V-shaped cutting edge is suitable for pointed fillets, turning dovetail profiles, round bars and much more.
• The diamond cutting edge has three large radii and three corner point cutting edges and can be used in two positions. This cutting edge is ideal for creating curves and finishing cuts, whether in long or cross grain wood when turned by 45°.

Fig. 5: The rake of the carbide insert is clearly illustrated in this photograph.

One size doesn’t fit all

A round shaped carbide tool works well for bowl interiors, however it doesn’t work so well on the on the exterior. The square shaped carbide scraper is effective on the bowl exterior, but not the interior. For these reasons you will probably require more than one carbide cutter shape to turn a bowl.

Negative Rake
Carbide inserts with 7° bevel angle and a 20° chamfer with a negative cutting angle are available to give a very clean cut even as in the scraping mode. The negative angle is not so aggressive reduces the angle to wood to less than 90 ° making it very safe to use and is particularly suitable for end-grain woodturning.

Fig. 6: Examples of Blackline Tools carbide inserts. Not the 7° bevel on the square insert.

Blackline Tools Carbide inserts come in the following range of sizes:

Diamond tip inserts
Diamond tip inserts are designed for turning all types of wood and composite material for longer life and could last up to 20 times longer than carbide.

Fig. 7: Ultra long life sub-micron RaZoR Diamond material by Blackline Tools.

The development of carbide tipped wood turning tools is believed to have simplified woodturning. These tools come from the manufacturer ready to use with a long lasting and sharp cutting edge, this alleviates need to purchase a grinding machine and jigs for sharpening.

Carbide inserts do wear out, and can be re-sharpened on a diamond plate or diamond suspended pastes, but eventually will need to be replaced.

It is relatively easy to shape and hollow a piece of wood using these tools as they are in essence scrapers, therefore it circumvents the time it takes to aquire the skill needed for using the standard gouges and chisels used for woodturning.

The area of unsurpassed performance by carbide tipped tools is when turning very hard materials like acrylics and epoxy/wood workpieces. These materials do have a blunting effect on HSS Tools that will require more frequent honing.

Best of both worlds.

My preference for fine woodturning and precision work is best performed with a traditional bowl gouge or skew chisel, making micro-fine smooth shaving cuts. However I am now turning with both traditional and carbide tools where it is appropriate and gives the best result.