Leaf type drilling knife set: 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm

A U-STAR set of leaf-type drill bits

Drills with a leaf-shaped, that is, spear-pointed tip differ from ordinary twist drills in the shape of the cutting part. They have no deep helical flutes to carry the swarf away, and so they do not bite into soft plastic as easily and do not pull the edge of a hole out into a white ring. Drilling with them goes slowly and with care, but the result is a hole with a clean edge that usually needs no further cleaning up. The name gives the diameters 1.0 mm, 1.5 mm, 2.0 mm and 2.5 mm.

Where the set suits

In the detailing and modification stage. Opening existing holes out to an exact diameter, opening the muzzles of barrels, exhausts and nozzles, preparing seats for brass tubing, holes for handles and antennas, ways through for wires. The diameters given cover most ordinary work in medium scales; for the finest holes for thin wire, twist drills in tenths of a millimeter are more suitable.

How to work with them

• Mark the spot out beforehand with a needle or a knife; the tip will then not slide across a smooth surface.
• Work up to the target diameter in stages from a smaller one, and the hole will stay round.
• Drill at right angles and without pressure; side force is the most dangerous thing for thin drills.
• Support the part or clamp it in a vise, so that it does not twist under the tool.
• Store the drills separately, as the tips are fragile and go blunt by knocking against one another.
• Before you buy, check that the shanks will fit into your chuck.

Who it is for

For modelers who add detail and want a clean edge after drilling with no repairs. This is a bench tool, not a kit or an accessory for a particular model.