We just learned about the Hole Saw.
So far we have learned about cutting metal using a lathe or a mill, putting holes in the metal by threading, boring or drilling.
Another type of way to work with metal is called Grinding.
This is a way to use one rough piece of metal or even diamond to scrape off metal, almost like using sandpaper on wood.
Usually a grinder is a metal disc called a grinding wheel, that spins around very fast.
There are different types of grinders like angle grinders or bench grinders that you might use depending on what you want to do with the metal.
(from: wikipedia - angle grinder)
(from: wikipedia - bench grinder)
(from: wikipedia - grinding wheel)
Kid Facts - Blast from the past: Blacksmith
