Fixcraft is providing a page-long explanation, tip sheet, and background history on the Cleat and why you’re going to like it so much:
For those who got the complete mallet kit or the shaft plus connect, you will have the easiest time of anyone putting your mallets together. It really is as simple as putting the shaft and cleat in place, and tightening it down. Anyone who has had mallet making parties, or screwed up a $15 shaft before will find a real zen quality to having a modular mallet building experience. We recommend putting the shaft through the mallet head almost to the other side, then insert the cleat as your mallet is head side up. Once the holes align, insert the bolt and hand tighten it. Don’t use a drill gun or get all crazy. As soon as it’s flush, you are done.