I bought this set of drill bits.
The set came with 3 colours of drill bits:
Silver Gold and Black
I do not know. What does each one of these bit colours mean?
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The tip style of the bits indicates their purpose; the colors mean almost nothing.
The ones on the left are called brad-point bits and are great for going through dimensional lumber. Depending on the region they could be colloquially called auger bits.
The middle are general purpose bits. They can do wood, drywall, plastics like PVC, and possibly metal. Their gold color might indicate that they are titanium-coated bits; at least that's what Milwaukee does. Black general purpose bits are usually black oxide. Different metals indicate different durability.
The ones on the right are masonry bits. They should be used for concrete, brick, plaster, stucco, etc...
Those pointy wide ones at the bottom are paddle or spade bits and are used for boring large holes in lumber. These usually max out at 1-1/2".
In the bottom right are your hole saws.
"It means" at one level, what surface finish was used, if any. Polished steel, black oxide, or titanium nitride (or cheap imitation gold-colored stuff pretending to be TiN)
However, by inspection (looking at the business ends of the bits) I can see that the "silver" ones are wood and/or plastic bits, the "black" are masonry bits, and the "gold" are metal/general purpose bits. For this set, only. All those types of bits can come in any of these colors, but in this set, that's what you've got.
This isn't a direct answer, but it might be useful. For drilling metal, i recommend cobalt steel bits. Standard high-speed steel (HSS) bits won't even penetrate stainless; they just turn into a glowing blob at the tip. But I use cobalt for all metal; it's just so much easier and faster. As a retired carpenter and fab shop employee, I have been through thousands of bits, and anything but cobalt when working with steel are a waste of time and bits (that you could save to work with wood and plastic). I say cobalt, but there are probably other alloys out there, just use anything but HSS on metal. OH--and please don't confuse cobalt, an element alloyed with steel in drill bits, and Kobalt, which is a brand name at Lowe's. Good luck.
Generally the shape of the tip is a better clue than the color to a drill bits purpose.
The bits on the left with a small point are wood bits.
The bits in the middle with a cone shaped tip formed just by grinding the ends of the shaft are general purpose bits. Suitable for materials like wood plastic and metals (though harder metals may be a problem for cheap drill bits).
The bits on the right with a blunt insert at the tip which is wider than the shaft are masonary bits. As the name suggests they are for use in masonary (brick, stone, concrete, plaster etc).
There aren't any in your set, but you also get "multipurpose" bits, which are consturcted in a similar way to masonary bits but the insert is sharper, these are handy when you want to drill holes through multiple materials.