Why are yellow and white screws stronger than black screws? Unusual self-tapping screws with a spiral and an asterisk

As soon as this fastener appeared in hardware stores, it immediately gained popularity. They practically replaced the usual nails for everyone. Self-tapping screws are convenient in that you can fasten many materials quickly and easily.

On sale there are fasteners (screws) not only in different colors. They differ in thread, tip, material, head, size, purpose. There are universal screws or specially for wood, drywall, metal, concrete.

Self-tapping screws are made from brass, carbon, stainless steel. Fastener coating: oxidized, galvanized, phosphated or uncoated. Oxidized self-tapping screws rust quickly in a humid environment.

Black self-tapping screws

Used on wood, metal. For wood, fasteners with a large thread, for metal with frequent.

This is the cheapest fastener. They have an oxidized, shiny surface, phosphated (matte surface). Black self-tapping screws are not recommended for heavy structures. Often, at the slightest mistake, the cap breaks.

We have to screw another self-tapping screw next to it. And if the fasteners are long, they can bend when screwed in. Fasteners cannot withstand bends and are not durable. Black self-tapping screws are good only for interior work for fixing drywall.

To prevent black screws from rusting, you can treat them with spray paint. Pour the fasteners into an iron can and sprinkle a little paint, cover and shake. Instead of spray paint, you can use silver paint.

Yellow, white self-tapping screws

More reliable galvanized fasteners. In yellow ones, it sometimes breaks off the slots on the cap, but the cap itself never falls off like in black screws. They do not start to rust as quickly as black and metal splinters do not happen during work.

All praise self-tapping screws infix. The special geometry of the point prevents the wood from splitting. They are comfortable to spin and they hold tight.

There are some unusual screws with an asterisk on the head instead of a cross. It is convenient to use as a fastener for a fence in the country. Not everyone has such a screwdriver, and it is impossible to unscrew such screws with a knife. They still have a sharp tip. The wood does not split when screwed in.

Spiral at the bottom of the cap before the thread. Probably in order to tightly pull one board to another.