Goldfish Development. Baby goldfish are born much darker than they will be as adults. This may be because dark colors helps these small, vulnerable fish escape the attention of predators. With proper husbandry, the fish gradually change color and develop orange or gold scales. Fancy goldfish may develop color patterns including white patches.
Posts: 1,396. Re: Bits for hand drilling hardened steel. If you want to experiment with carbide drilling on the cheap, buy a carbide tipped masonry drill bit set. They are about $20 a set new, but I find them at garage sales for about $1 for the set all the time and that's why I use them.
Metal Drill Bits. These are known as high-speed steel (HSS) bits and are characterized by their black color. More expensive, durable ones may contain cobalt or be titanium-coated. They can also be used on wood or plastic, but they last longer if reserved for metalwork.t cannot be used with the drill in reverse action. A hole cutter bit (right) sometimes called a hole-saw, comes in various sizes for cutting wood and metal. The drill bit cuts first, then the round cutter makes a larger hole.