In knife making: What is a belt grinder used for: to grind away excess metal, to both profile blade countour-wise and to grind it so it has
a cutting edge. Contact wheels of different sizes and flat platens are used
to obtain desired shape.
Of course one's not limited to grinding metals. Wood, micarta/G10 etc are all extensively used as handle material and are also ground to shape via belt grinder
What is a surface grinder used for: to flatten out metal to where it becomes "precision ground" - perfectly flat to within less than a 0.001"
What is a mill used for: to remove metal in a very controlled fashion, including drilling, milling, boring, face cutting etc . For example: integral blade where 3/8" thick blank is to reduced through milling to 1/8" blade, thicker handle, bolsters etc (sizes just for illustration) . Again,
all kinds of materials can be worked on with mill
What is a lathe used for: to remove metal in controlled fashion, mostly via turning & drilling. You can also bore, grind, thread etc all using lathe.
What are files used for: to remove metal by hand. If you're good with file, you can do pretty amazing things, including very intricate ornamentation
What is an anvil used for: as a solid based on which to forge metal (when heated up to forging temp, metals become soft and can be whacked into desired shape by hammering. Both hand and mechanized hammers/presses are used)
What does the term ''satin finish'' mean: the opposite of "mirror" finish. Many folx find mirror finish hard to mantain, any scratch just jumps @ you. It is also pretty hard to accomplish (lotsa buffing). Thus satin finish, where blade is sand-papered lenghtwise with some fine grits.
What is ''heat treating'': some steels harden when first heated up to certain temps (1450F-2000F, depending on steel) and then quenched in various mediums (air, oil etc). You want your knife's edge to be rather hard to have/retain cutting qualities, but not too hard , where it becomes
brittle. Proper heat-treating techniques allow one to accomplish that