Please do not hit with a spanner, a hammer, a screwdriver, or just put it all together and tighten till it pushes it down. Hitting with a block of wood is prob the best being that the material is much more forgiving on your crown race, out of all those options, but by al means just go and buy a tube the right size and then you will have one for as long as you ride. If you keep rigging tools for your bike, the parts WILL eventually fail, and then we get a post on here "why did my headset explode, Chris King sucks....etc...." when its the users fault. Putting the race on and tightening is THE WORST idea ever. Fook the whole headset up that way, and if you get lucky, maybe ovalize the headtube. Congrats. Do it right. Get the tool or just buy a pipe the right diameter. Cant be more than a few $$$....