When the door is open you can see the hinge plates and the cylinders.
How deep do invisible hinges go into the door.
Insert 5 8 inch screws into holes on the lip on.
And they have some pretty awesome doors hidden door latch.
Hidden hinges have four round cylinders.
For things like panic rooms this will be a necessity.
The door ended up 8 tall and 6 wide with wall texture and paint applied to make it go away.
There is no way to access them when the door is securely locked.
I used some very large and not inexpensive soss hinges which worked well but they didn t have the adjust ability like the sugatsune brand you use.
With soss invisible hinges there are no pins to remove because the entire hinge mechanism is built into the door frame.
Tap the cylinders marked d into the hole in the door until the lip on the hinge is flush with the door.
If your door securely closes it will need a latch.
Invisible hinges are not really invisible.
However if the secret room is more of a novelty a.
When the door is shut the cylinders drop into routed out recesses or mortises in.
Soss makes the best quality invisible hinge in the world.