Caution as this is so loud, you may not want to try it indoors!
Please check out my other instructables and I also have a diy podcast called mechanicalmashup.tv
Step 1: The hands
Step 2: Holding the acorn cap
Please excuse my hands, as an industrial mechanic, this is about as clean as they ever look.
Step 3: The blow
Blow hard. It will probably take a bit to figure it out right but when you get it, it will be loud!