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.
Flame-hardening is an ideal, time-tested method for steel hardening. And there are several types of steel that work well for the flame-hardening process. One example is hardening 4140 steel. Another is hardening 1045 steel. Flame-hardening cast iron has also been done with success. The clutch plate shown in the photo below is made of cast iron, as is the cam shaft sample shown to the right.