OK for a few holes but poor quality. useful set, not the right tool. After the first hole, which took about 5 times longer than it should have, with the blade squeaking and burning and overheating my powerful Makita drill bit, it was obvious there was a small tooth misalignment. It is enough that there is a gap between the cup and the hole to be drilled. The same goes for the severed slice of wood, which is stuck in the cup so tightly that you can only get it out by disassembling the tool, which will burn your skin if you dare to touch it. Long horrendous cutting time with an even longer cool down time, followed by a full stripping to remove the wood and you're good to go again, hooray! I managed to cut all 12 holes but the blade is finished, all the teeth are overburred and dull. I'm exhausted, frustrated and my fingers are burned. Next time I'll use the right tool.