Slotted countersunk screws ISO 2009-brass M4x10 mm

Slotted screw drives are the oldest form of rotary drives for fastening screws. The Schltz is usually manufactured in a pressed or milled version. Because of its uneconomical processing method (slow, unwieldy), the slot is increasingly disappearing in favor of other drives (hexagon socket, cross slot, hexagon socket).

Brass is a copper-zinc alloy containing at least 50 per cent copper by mass and up to 45 per cent zinc. Other metals are added to impart specific properties to wrought and cast alloys. Brass is wear-resistant, corrosion-resistant, easily formed both hot and cold, and can be polished. Wrought alloys are used in deep-drawn parts, screws, springs, tubes and instrument components, whilst cast alloys are used in valve bodies, plain bearings and precision engineering components.

The term plain indicates a completely untreated, merely oiled, smooth surface for all DIN and ISO screws such as wood screws, hexagon head screws, threaded rods, nuts and many types of washers.