Drum Tuning Lock

I created this with my basic 3d modelling skills on Tinkercad. The floor tom on my Premier Genista kept going out of tune because of the low tension and vibration. It's not a thing of beauty but it works. I would be very happy for someone more skilled to improve on it.
The important measurements are the size of the two square holes to make the star shaped hole. They need to be 5.3mm across.