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Twist drill
Twist drills with a roof-shaped point and a short robust shank are mainly applied for dowel bit bores in solid wood or cross grain wood.
Special dowel bit drills for multiple bores (which can be carried out with dowel bit drilling machines) have a screw on the robust shank.
Twist drills with a backed centre point (with 2 cutting edges) are applied for exact and clean through holes mostly across the grain.
Figure 4 - Twist drill
1 twist drill with roof-shaped point, 2 dowel bit drill, 3 twist drill with centre point
Auger bit drill
They are mainly applied in hand drilling machines for deep bores.
Figure 5 - Auger bit drill
Cylinder drill
They have a cylindrical bore head with which and dimensionally stable plain bores are carried out on even bore ground. They mainly have a larger diameter. They are suitable for boring out of defective parts and knots.
Figure 6 - Cylinder drill
1 round shank Forstner bit drill, 2 circular rim auger bit drill
Wood disk drill
They are also suitable for boring out of knots; but are mainly applied for manufacturing wood disks (cross wood dowels) which are placed instead of a drilled out knot.
Figure 7 - Wooden disk drill
Countersinks
Depending on the form of head, conic bores for flat head screws can be manufactured or bores can be cylindrically enlarged in order to countersink screw heads.
Figure 8 - Countersink
1 countersink, 2 counterbore
After having finished drilling resin and dirt residues must be removed with hot water, petroleum or thinner!Slight lubrication with acid-free grease protects the drilling tools against corrosion!
With which type of drill can be large bores on a even bore
ground
manufactured?
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What are countersinks applied
for?
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