MEINL Percussion Soft Foam Rubber Standard Cajon Beater

I use this on a pedal with a cajon. Firstly, it sounds great. Nice deep thud as well as slappy attack. But the head swivels up too easily, it is just a little too loose. I start the song with it parallel to the cajon surface, then a couple kicks in and its facing upwards, then Im hitting my cajob with only the edge of the beater. Not good. There is no way to tighten it. You can see the horizontal swivel space in the picture. There is an allen socket on the side, but it is only for securing the joint that hold the rod to the beater head. Ive got it as tight as it can be, and it still moves freely. So not very useful at all, really. I'm gonna try to jam it up with something.