Print this with latest cura (with arachne engine), 0.5mm width, 0.2mm layer height and perfect bed leveling to have great top surface. 

You need 30x 5mm M2 countersunk bolts (recommend hex or torx for looks!) + 30x 3mm brass inserts. 

Long neon bulb is recommended, I used old Tesla tube that's not made anymore. Closest thing I could find that's still being sold is A1A neon bulb:

[https://www.digikey.cz/en/products/detail/visual-communications-company-vcc/A1A/4176016](https://www.digikey.cz/en/products/detail/visual-communications-company-vcc/A1A/4176016)

You can also use two small neon bulbs but always make sure to apply heatshrink isolation on the leads!

Github:

[https://github.com/mcer12/Nick2-Nixie-Clock](https://github.com/mcer12/Nick2-Nixie-Clock)