Spoon bits are made from tool steel, a variety of steel that contains a high carbon content to increase its strength and hardness.
While the forging process heat treats the steel in a spoon bit, the bits do not undergo the same hardening process as some other tools, and remain in a softer state.
The fact that spoon bits are softer than other bits means that they can be gripped more easily in the chuck jaws of a lathe, as the teeth of the jaws can squash into the bit more easily and hold it firmly in place.
It also means that the bits are easier to sharpen.
Despite being softer than other types of bit, spoon bits are still more than hard enough to cut through wood.
As they need to be sharpened relatively often, spoon bits are usually made without coatings. Sharpening the bit would remove any coating from the edge of the tool and compromise any corrosion resistance that the coating would offer, so it makes sense not to waste money on it!
