Tungsten Carbide Forstner BitsⅡ

In last part we know that tungsten carbide Forstner bits are for drilling deep and precise smooth-sided holes through in wood working and come in sizes from 8–50 mm (0.3–2.0 in) diameter. Here we simply explain the basic structure of the bits.

The tungsten carbide Forstner bit includes a center point which guides it throughout the cut (and incidentally spoils the otherwise flat bottom of the hole). The cylindrical cutter around the perimeter shears the wood fibers at the edge of the bore, and also helps guide the bit into the material more precisely. Some of the bits have a total of two cutting edges in this cylinder. Forstner bits have radial cutting edges to plane off the material at the bottom of the hole. Some of the bits have two radial edges. Other designs may have more. Forstner bits have no mechanism to clear chips from the hole, and therefore must be pulled out periodically.

Sawtooth bits are also available, which include many more cutting edges to the cylinder. These cut faster, but produce a more ragged hole. They have advantages over Forstner bits when boring into end grain.

(To be continued. This article is divided into several parts. Here is part 2. For part 1 please refer to  http://news.chinatungsten.com/en/tungsten-information/80700-ti-10454)

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