Introduction: Secret Safe Compartment With Hidden Door and Magnetic Locks
Welcome to my 3rd Instructable.
Last week I was in a friends house and he showed me a sturdy looking cupboard in his home office that he had bought second hand for next to nothing. It had a safe secured into the bottom of it but as my friend pointed out it was on full display to anyone who opened the cupboard doors making it not very safe at all. When I saw it I straight away thought of the Fix-It contest that I had seen on Instructables and thought that fixing the problem with the safe being visible would be a good upgrade project to post. My buddy was intrigued so I took some measurements and went back a few days later with some materials and tools.
The plan was to replace the two existing shelves which were not good anyway as they had a big gap at the back, with two new full size shelves and fit a concealed door in front of the safe at the bottom of the cupboard with some kind of disguise and a completely invisible locking mechanism.
I visited the bargain corner of IKEA where they often sell spare shelves or panels from their flat pack furniture and kitchens. I found two identical black shelves that were a bit too large but could be cut to size.
I also got some 2"x1" planed timber from a hardware store, a short piece of 8mm dowl, some screws, some medium size rubber orings and 4 small cylindrical neodymium magnets.
My tool box is very limited so I made do with the following:
Handsaw, small battery drill, screwdrivers, razor knife, wood saw on a penknife, ruler and pencil.
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Step 1: How the Concealed Magnetic Lock Works
I made a Sketchup model of the door while planning how it would work and settled on the design in the pictures. I thought about having horizontally moving magnets at first but tests showed that the friction was too high unless the 'operating magnet' was very close which it could not be because of the thickness of the door. So I settled on a vertical type lock with gravity to help closing the lock.
The lower of the two shelves sits on top of the safe and the door slips in underneath the front of the shelf. The locking mechanism involves two cylindrical magnets which sit half in a piece of wood attached to the door and half in a piece of wood attached to the shelf above the door kind of like a shear pin stopping the door from opening out. Two more magnets when positioned on top of the shelf above the door locks lift the magnets up out of the block attached to the door and fully into the recess in the block attached to the bottom of the shelf allowing the door to open out.
Step 2: Making the New Shelves
The two black shelves from IKEA needed to be cut down to the size of the cupboard. The upper shelf then just sat on the little metal supports from the old shelves. The lower shelf was going to sit on top of the safe so I needed to cut and attach some pieces of the 2x1 to allow it to be secured in place. I also attached the upper part of the magnet operated door lock and a door stop in the centre of the shelf so that the secret door would have something to sit up against when in the closed position.
In the picture the 3 securing blocks are the ones with screws sticking out of them. Then on each side there is one block for the magnetic lock and in the centre there is a door stop block.
Step 3: Fitting the Shelf and Door Stoppers
I also added two door stop blocks to the bottom of the cupboard so that the door would sit up against them when closed. Beside the door stoppers I drilled shallow 8mm holes. Two short pieces of dowl attached to the inside of the door and protruding just below it locate into these two holes and stop the bottom of the door from moving or being pulled out when the door is closed.
In the second picture you see the lower shelf in place on top of the safe. I placed a few old rubber washers on top of the safe to stand the shelf off the safe a little bit so that the shelf would not sound noisy when things are put into the cupboard which it might sitting directly on a metal surface.
Step 4: Making the Door
I made the door from one of the old shelves which were already the perfect width. It was too tall so I cut it down to fit under the lower shelf and cut out holes where I mounted two old double gang sockets. I have no jigsaw or fretsaw so I drilled holes around the outline of the back of the sockets and then used the saw on my penknife to finish the job. A piece of 2x1 across the back of the door and some long wood screws into the holes in the sockets secured them in place.
Two pieces of dowel were cut and initially mounted on the back of the door using duct tape but then screwed and glued later. These had to be perfectly aligned with the holes that I drilled in the bottom of the cupboard.
Finally I added two blocks for the magnetic door lock. These blocks need to line up with the blocks on the shelf above the door and the hole drilled in each block for the cylindrical magnets also need to line up perfectly. To achieve this I removed the shelf from the cupboard, put it down flat upside down and then offered the door up to it in the position that they would be in when the door was locked closed. In this position I marked up the locations for the blocks and screwed them to the door. Next I drilled holes in the blocks on the door and then used homemade dowel joint pins to mark perfectly aligned points on the blocks attached to the shelf so that I could also drill them.
Step 5: Testing the Door
The door needed a little bit of sanding and jiggling to get it to fit properly. The holes for the magnets needed to be enlarged slightly as they were 8mm holes and the magnets were also 8mm magnets that I got on Amazon. But after all adjustments the door operated fine as you can see in the video. I did add one rubber oring to the inside centre of the door held on with duct tape just to take up a small amount of play that existed when I first assembled it. More accurate locating of all the parts and blocks would probably have made this unnecessary.
My friend added two labels above the sockets to make them look like UPS power supplies for the computer server equipment that he plans to install on the bottom shelf. (I will probably have to add some cooling fans and power to the cupboard for that later). The spare old shelf was kept at the top of the cupboard as it needed an extra shelf.
So that's it. I'm sure these magnet type locks can be used in lots of different ways on different projects. Just a word of caution. The magnets are small but very strong so don't let them jump together because they chip easily and can pinch skin and fingers as well. Comments and suggestions for improvements welcome!
This is an entry in the
Fix It Contest