I meant to get a countersink for wood. Then in the hardware store, beside the countersinks, I saw a glass/tile drill bit set, which as a pack, is not so much more expensive than a single countersink. So, I got those glass/tile bits.
Now, I have a problem whether these bits would actually last. I suppose these are Tungsten Carbide & perhaps cut more so with it's hardness (chipping at the ceramic or glass) than with a sharp edge. I haven't opened them, but I assume them to be sharp. So if I used these & the sharpness wears away on its intended use, it's still good for the intended use. But, for wood, without the sharp edge obviously, it won't bore well.
Am I wrong here?