Intro: Hidden Drawer Safe
When building a hidden drawer there are a few important decissions that need to be made. Location is one of the primary decisions you will be faced with. Luckily, I was in the middle of designing a piece of furniture where the safe was easy to integrate but the overall design of this slide motion/latch/trigger mechanisms can be moved into any "draw" type project. Next is reigning in the slide motion/latch/trigger design. I'm going to cover this in a little more detail before I venture into my project just to give an understanding of why I made some of the choices that I made.
When building a drawer, the slide motion begins with a drawer slide. In this case roller drawer slides are pretty much only going to vary by length and strength. I used 24" TopSlide® Series Heavy Duty Slides that I purchased online from Rockler.com.
Next, and a bit more complicated is the motion. Options for motion include Springs, Electric motors, or Hydrolics. I'm going to stay away from the Hydrolic options and focus on the motors and springs. Electric motors or linear actuators, give you the ability to open and close a drawer with the push of a button and can be smooth, quiet and strong. If you prefer motors great but, I ran into a few negatives when trying to rationalize a motor for my design. The first issue that came with the motor was the latch. A motor eliminates the need for a latch because you can establish its limits electronically. As long as the motor is reasonably strong you should be ok. however, I ran into issues when it came to the failsafe I wanted. What I mean by this is that the drawer, using a motor would require a complicated disengage so that you could still open the drawer in the event of powerloss or motor failure. This is by no means impossible but I found it to be more complicated. A motors motion control options are quite tempting though... just not where I felt I should go. This brings me to the Gas piston spring. The 24"easy lift from www.bansbach.de/com ended up being what I decided upon. This gas piston cost a little over $100 but offered a controlled slow release and an adjustable pressure level. Using a gas spring required a latch assembly but gave me all the features I wanted.
So Materials break down to
Drawer (steel in my case) $120
Drawer Slides $50
Gate Latch $10
Electronic door strike $25
Gas Spring $120
Misc nuts bolts and screws $5
Electric knife $25
Oh and I have plans for some polished concrete medallions to decorate the entertainment center with. A laser cutter would go a long way in helping with the molding design process. Sounds like another instructable to me.
Step 1: Drawer and Hindges
The drawer itself was fabricated at a local machine shop out of 16 guage steel. However I prefer to measure once and cut twice so I had to cut the thing in half and re-weld it. I neglected to account for the 1/2 inch thick drawer slides in my original dimensions. I never learn!!!
The hindges are attached to the inside right and left portions of the drawer passage using several wood screws and connected to the drawer using pand head machine screws, washers and nylon lock nuts. I suggest investin in a "step bit" or "Unicorn bit" so you can drill out the necessary holes in the steel drawer. These bits are typically used in electrical work and will eliminate the burs left by a standard bit.
The facade of the drawer is made out of a solid piece of Birch attached with half inch pan head wood screws. I deliberatly made the screws smaller in order to allow the facade to be sacraficial, pending any forceful attempt to pry the drawer open.
If i did it again, which I may, I would have lined the drawer hole with a steel sleave and moved the drawer thickness up to 1/8 inch stainless steel. Cost was a factor here and considering the hidden nature of the project it seemed unnecessary.
Step 2: Gas Spring
The gas spring will vary based on specific drawer dimensions and design but the instillation will be similar. The use of a ball socket joint end and bracket will allow for a smooth rotation as the drawer opens and closes. This will also give some wiggle room when it comes to installing the spring. Meaning you will not need to mount it exactly perpendicular and or level to the drawers face or range of motion. The gas springs are available with fast normal and slow extension speed. I went with and adjustable force slow release. The adjustable force allows me to get the push in force dialed into what is most comfortable. Be careful with the adjustable force option because if you release too much then you have to ship it back to Germany to have the cylinder recharged. I don't know if it is necessary but I have mine set a little stronger to allow for a breaking in period. I did this just as a precaution.
is a great source for figuring all of this out. They also have a variety of other motion controllers motors and actuators.
Step 3: Electronic Strike and Latch
The electronic strike is mortised into a block of oak and bolted to the center rear portion of the drawer passage. The gate latch is mortised into a matching block of oak and attached to the rear of the drawer using 1/2 inch threaded rods. The treaded rod may seem a little strange but it really allows me to make the necessary adjustments to get the two matching perfectly. All the nuts used are nylon lock nuts paired with fender washers. Again, use a unicorn bit to debur the holes drilled in the rear of the drawer.
Quick point on the electronic strike. You can use either a electronic strike like the one I use here or an electro magnetic strike. The magnetic strikes are quieter but require a continuous draw of power in order to stay engaged. This not only seemed wasteful but would open the drawer in case of failure. due to obvious safety concerns I did not like this. The standard electronic strike makes a slight buzzing sound and cannot disengage if there is force applied to the strike. The gas spring keeps a continuous force on the strike. This may seem like a disadvantage but it requires that you give a light push to the front of the drawer in order to disengage the strike. I see this as a pretty nice safety feature. not only do you need to know where the keypad is but you need to know the combo then know the location of the drawer and finally that you have to give it a little push in a specific time frame. If you do not like this then you could use the magnetic version.
Components were purchased from http://www.smarthome.com .
Powering can be done using a power supply available from Smarthome, or read on for what I did.
Step 4: Keypad and Power
The keypad is an Enforcer Digital Keypad which was also purchased from Smarthome.com. This is the real heart of your setup so it is important to be aware of the options this poses. This keypad allows you to set up multiple users, master passwords, temporary passwords and just about anything else that you would want. This also has some nice tamper resistant features.
Powering can be done by purchasing a plug in AC power supply orrrr... you can connect the keypad into a household alarm system. The tie into the alarm system gives you the ability to use some of the strongest security features of the keypad. False codes can trigger your alarm system. Tampering with the keypad(attempting to remove) will trigger the alarm system. Specific code entries can trigger the alarm system. More importantly the keypad is powered by your alarm systems backup power supply in the event of a power outage and or power loss.
I used some stiff exterior sprinkler wiring to wire the power and alarm system together. Yes this is overkill seeing as Rj-45 would work perfectly but the rigid nature of the sprinkler wire allowed me to feed the wiring throughout my house a little easier, and I had plenty left over from a sprinkler project.
Once the keypad is wired you attach it to the electronic stike using the same wiring.
Hiding the keypad is as important as hiding the drawer so you need to think about what inconspicuous place you want to put it. I made a false facade to the right of the drawer that blends in perfectly and folds down to reveal the keypad.
The faux door is installed using two hinges and some mortised rare earth magnets. To install the magnets all you need to do is use a Forstner bit to drill out the hole and screw it in using a sleeve that comes with the magnets. The magnets were purchased at Rockler.com.
Just an FYI, you can use almost anything to trigger this style of strike. Some of the options available out there are; keypads, Bluetooth switches, keys, knock sensors, push buttons, timers, IR swithces, motion sensors. You can also create a series of switches or actions that need done. Imagination is you limit. You could even tie it into that clapping bra ible if you'd like.
Step 5: Foam
The foam I purchased was High density firm foam from http://foamforyou.com . Say that three times fast.
The easiest way to get a clean cut out of foam is to use an electric knife. The knifes are like $25 from target and work really well. If you prefer, you can even mount the knife on a router table to get a true 90 degree cut. There is a video I remember seeing online somewhere that illustrates how to do this. I found that the knife worked out perfectly by hand.
First, I worked everything upside down so that any markings were on the underside of the foam. Lay out what you want. In my case they were guns but it could be anything. Trace the items with a sharpie and remember that it is upside down. Once everything is how you prefer then lay the sheet out on a flat open surface and plunge the knife in following as closely and as perpendicular to the line as possible. Be careful!!! you are working with a carving knife after all. I'd like to keep my fingers as should you.
Once I had the cutouts I took the scrap and cut it in half to act as a cushion in the drawer. This is not necessary but I think it looks nice. This cutting in half was a little difficult and I think I'd make some form of jig if I did it again.
Step 6: Backups
One thing that I did that I'm not going to detail is work in backups. You should always have a way to get into your draw in the event that you have the unforeseen occur. Redundancy is always a plus.
I find that a mechanical way of disengaging the lock is imperative.
I hope you enjoyed the project.