Crazy. It comes with an Allen key, but the instructions don't mention how to use it or what it's for. The lock nut looks like you could use a wrench on it and I'm assuming you can. The two holes in the lock nut fit a hex wrench. You insert the hex key with the short side in, hold the locking knob on the top of the angle grinder (on the other side of the wheel), and then turn the hex key clockwise to tighten it. On the contrary, to weaken. Reading the description I thought the grinder came with…