The turntable is mounted on a big old ball bearing that I had in my useful box so it rotates very smoothly.
Just working out how I'll fit an internal lock - (probably an ordinary Lockwood dead lock that will stop the 3 locking bars inside from moving), so the key hole will be pretty flush with the front of the door. I'd rather not use a padlock coz they can be attacked from outside with bolt cutters and they look a bit...ummm...."lumpy".
It'll be bolted to the floor with bolts under the turntable ( which dismantles for installation). I have a workshop full of lathes, cutting, bending, squashing and welding gear. Oh, and a back yard (non ferrous) foundry to cast my new reloading press that'll be my next project.
Making steel do what want kinda gets me going
There's still a few of Wile. E Coyote's ideas that I haven't tried yet.