Best Mounting bracket

I have the 12V Low Noise DC Motor 146RPM w/Encoder.

While I like the motor very much, I’m having some trouble mounting it to anything. It seems to be a slightly weird size. I bought the Pololu 37D mm Metal Gearmotor Bracket with it, but they’re about 2mm too big (in diameter), so I can only get one screw in, which isn’t really enough to securely attach it.

Can anyone advise a bracket that could work, or an alternative means of securely attaching it to something?

Thanks

Unfortunately, we don’t offer an exactly matching bracket for the 12V Low Noise DC Motor 146RPM w/Encoder