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.
For most household projects, a high speed steel drill bit is sufficient. When you're drilling through hardened steel, however, a strong, heat-resistant drill bit is needed. A titanium drill bit is good enough for most home projects. However, if you do a lot of drilling into hardened steel, a cobalt drill bit, although expensive, will provide long-lasting performance.