Drill Bit 2.5mm L10-25

Mineshima modeling drill bit of 2.5 mm diameter

A single drill bit from Mineshima, the Japanese maker of modeling tools. The diameter of 2.5 millimeters is given in the designation of the item. It is a tool for the modeling bench, not for a workshop: it reckons with thin walls, small parts and materials that do not forgive a heavy hand.

Drilling into injection-molded plastic

Polystyrene is soft and behaves treacherously when drilled fast: it heats up, starts to stretch and the hole partly closes up again behind the bit. On a thin wall, by contrast, a crack appears easily when you press on the bit. The remedy is slow drilling with minimal pressure and with the part supported. The material then comes away as a proper chip, not as a melted loop.

Work tips

• Lower the speed or drill by hand, because heat is a greater enemy with plastic than a blunt edge.
• Back a thin wall up from below with a piece of wood or balsa.
• Do not press the bit; let it cut under the weight of your hand alone.
• Take the burr off the edge of the hole with a scalpel, not with abrasive paper over the whole surface.

Who the drill bit is for

• Builders of plastic kits who add holes for pins and accessories.
• Modelers who modify moldings and open up blanked-off places.
• Anyone who wants to add a single diameter instead of a whole set.

The drill bit is a tool with a sharp point. Store it out of the reach of children and protect your eyes while drilling.