These USB chargers are fairly inexpensive and I use one for my USB needs at my printer. (Dessicant fans, lights, vacuum pump…)

The design of the charger was conducive to a drop-in bulkhead mount.

So, I threw one together. Sized for #6 screws, slice with the wide opening down for a no supports print. 

I have 2 of these chargers, the one shown, and another.

If you print this, please post your make.