Forstner bits are superior bits for drilling wood because they are guided by the rim and not a centre point. Hence they are not deflected easily by the natural differences in hardness found in timber such as knots or strong grain patterns. They can be used to be bore in any direction and are extremely useful for boring holes on an angle or to true up and increase the size of an existing hole or timber imperfection.
The design permits large chip clearance easily and this combined with their ability to track truly makes them especially suited for drilling deep or extra large diameter holes. Extension bars are available for this purpose.
All the bits in the set are true forstner bits up to 22mm with all bits 25mm and larger having a sawtooth design. A sawtooth design makes them able to cut more easily when drilling with the grain (such as through end-grain). They still retain clean cutting characteristics when used drilling across the grain but just not as clean as a true forstner bit - although acceptable for virtually all wood boring.
Beware of other metric sets and included sizes! We have selected the fifteen most popular and common metric forstner bit sizes so that you have the most useful set in the one purchase. Make sure you compare the sizes before buying.
Sizes included in this set are - 10mm, 12mm, 13mm, 16mm, 19mm, 22mm, 25mm, 28mm, 30mm, 32mm, 35mm, 38mm, 40mm, 45mm and 50mm.
Sharpen by running a small flat diamond plate along the horizontal scraper cutter keeping the angle constant. The rim needs less frequent sharpening but can be touched up using a round file or diamond stone on the inside. Never grind or touch up the outside of the bit.