The clock is based upon an Arduino Uno using a RTC module.  The display is a 16x9 Charlieplexed LED array.

The 'nixie tube' consists of a machined aluminium base that is matched to a glass tube.  I laser cut a couple of cirular plates that clamp the top and bottom of the display using four small 3mm rods that are secured with collars.

To add a bit more of a vintage feel, I've used a small piece of copper mesh at the front of the tube.

The box is one of the common pine boxes you can find at craft shops which I've stained.

How to use:

The clock just scrolls the time repeatedly.  To set the time, I've managed to use just one button which you push to increment the time.  If you want to set the hours, you just wait until the hours have scrolled into view and push the button to increase the hours.  Simlarly with the minutes.

I've also coded the display so it is dimmer in the hours after 17:00 and even dimmer in the night hours of 00:00 to 6:00am.