loading
Picture of Magnetic Combination Lock Picture Safe
100_1868.JPG
100_1863.JPG
Picture 10.png
100_1666.JPG

Why I would love to win a zing laser cutter...

Since I was little, I have been taking things apart; for years, I have been looking through and learning from Instructables. I love inventing, prototyping, designing. I love it so much I started a very small product design business with my wife from my home, where we design, cottage manufacture, and sell my own original products. As with most dreams lots of work is involved. Any help I can get that lets me focus more time on designing innovative products and less time on the day to day mechanics of putting those designs into action will allow me to reach my dreams.

A laser cutter would speed up my prototyping phase of product design. With more efficient prototyping, I can increase my output and troubleshoot faster. A laser cutter means more opportunity and faster innovation. I can certainly get my business going on my own, but it won't be as fast or as fun as if I won a zing laser cutter!


What I did to show my skills...

In this Instructable, I will show you how I created a great magnetic combination lock that be can be installed in an application, where you would like to leave no evidence of a keyhole or combination lock with the same security of both.

Inspiration came from a book my wife bought me on vacation from a thrift store: The Boy Mechanic: Volume 1 by Popular Mechanics Co. A very fascinating book detailing projects that popular mechanics published around the turn of the 20th century for boys to build. One project shows how to build a wooden combination lock. That intrigued me, so I built a simple version out of scrap wood. That got me thinking about locks. What I thought would be really great would be a magnetic version of the combination lock. So you could pull the key off, and no one would know it was even a combination lock. So after lots of tinkering, drafting, and failing I departed a long ways from the wooden combination lock design they had and came up with my original Magnetic Combination Lock. I am sure somebody may have done something similar somewhere, but I am unaware of it.

Before we get into the details, please check out the video down below so you can see the finished product and how it works. I would like to point out that the goal of my build was not to create an indestructible safe, but rather to prove my concept of a magnetic combination lock that was functional enough to keep honest people honest. However, the design can easily be implemented with much sturdier materials with little modification to make a safe that would keep dishonest people honest.

--Please read the safety disclaimer at the bottom before attempting to build.--




SAFETY DISCLAIMER: (Not many people like this part, but when you use big tools you take big risks when handled poorly)

If you attempt to reproduce this instructable, you will most likely be using sharp, pointy, dangerous, fast spinning, grown-up-person tools that can cause serious harm or death to yourself and others, especially if not trained properly on how to use them. You should have read all the safety warnings for your tools and understand how to use them. You should also use your tools as intended by the manufacturer with the the proper safety equipment.

Also, you may purchase powerful magnets that can cause serious injury to yourself or others if handled inappropriately (E.G. inadvertently or intentionally allowing them come together too quickly which can cause the magnets to violently explode and send little tiny sharp metal shrapnel bits into your eyes.) You should read all the safety warnings and understand proper magnet handling protocol to reduce the risk of injury to yourself or others. Please use appropriate safety equipment (e.g. protective eye ware, etc...)

I am not responsible legally or otherwise for any harm, injury, damage to property physically, financially, or any other unfortunate thing you may do. If you choose to build from this instructable. PROCEED AT YOUR OWN RISK!

 
 
Remove these adsRemove these ads by Signing Up

Step 1: Materials


What I used...

I am sure you could substitute in your own preferences where appropriate. My goal was to use as much of what I had on hand as possible. If you don't have the same items on hand, then I would suggest improvising. Although everything can of course be purchased online, or at your local hardware & lumber store. My cost was about $20 - $30. If you had to purchase everything, it would probably cost around $50 - $70.


FOR THE MAGNETIC COMBINATION LOCK MECHANISM & KEY

0.75" Thick HDPE Plastic*
2" dia. x 0.625" HDPE Plastic (Only required if you don't have the ability to turn a rectangular piece of HDPE on a lathe to a 2" cylinder. Make sure the surface finish on the ends is a high quality, not rough cut. These are actual dimensions, not nominal.)
17x 6mm dia. x 1.5mm Neodymium Magnets Grade N42*
4x 0.375" dia. x 0.75" Neodymium Magnets Grade N50
3x 1.25" Smooth Shank, Flat Head 3d*
1x 2.5" Long Furniture Finish Nail, Smooth Shank, Brad Head 8d*
0.093" Thick Plexiglass
2x 8-32 Aluminum Rivet Nuts*
1x 6-32 Aluminum Rivet Nut*
2x 8-32 Pan-head Machine Bolt & Nut (ferrous)*



FOR THE PICTURE FRAME & SAFE DOOR

0.75" x 1.25" x 58" of Oak (Actual Dimensions)*
0.75" Birch Plywood (Actual Dimensions)*
8x 1.25" Furniture Finish Nails*
Wood Glue*
0.093" Thick Plexiglass
2.5"Aluminum Tube (Inner diameter should slide freely over 8D Brad Head Smooth Shank Finish Nail)*
Wood Stain & Clear Coat



FOR THE WALL SAFE

0.5" x 3.5" x 78" MDF*
Wood Glue*
0.75" Drywall Screws*
0.25" x 14.5" x 24" MDF*
1.5" long Wood Screw*
2x Concealed Cabinet Hinges*

A Few Inches of Metal Plumbers Tape or Hanger Straps

*These Items I had lying around. I prototype and design products regularly for a living. Don't feel bad if you don't have them because the internet or a local supplier will. :)


IMPORTANT TOOLS I USED:

Machining Mill
Metal Lathe - Optional if you buy HDPE 2" Rod for the tumbler instead of rectangular HDPE. I had lots of rectangular HDPE.
Drill Press
Cordless Drill
2 1/8" Forschner Bit
Patience


A Note About Necessary Tools...

I know a mill and lathe are not the most common shop tools. I have them, so I use them. They do make life much easier to prototype precision parts.

But I wouldn't let not having those tools stop me from trying to build a magnetic combination lock. The main material I used for the lock was HDPE plastic. It can be worked with most wood working tools. Of course not as precisely; however, modification of my design for greater tolerances should allow you to get by with a basic wood working setup e.g. drill press, bench jig saw, dremel, and exacto knife to clean up edges. The tolerances really could be much looser. Like I said, I have the tools, so I use opportunities like this to practice precision milling. There is something very satisfying about drafting a part and then creating a real world duplicate within a few thousandths of an inch. But please don't let the precision tools scare you away from trying a similar design if not the exact same. It really should be quite doable with an extra helping of patience.


You can do it...

If you think things through carefully and use some creative techniques, you can probably do this all out of wood--except for the locking pins and magnets of course. My first non-magnetic combination lock was out wood. However, you may need to use more powerful magnets if you're not careful to keep minimal drag on all moving parts, especially any of the moving parts that are moved by the force of the magnets.

Although I should warn that you should be cautious about using overly powerful magnets they can be dangerous.

Step 2: Machine Magnetic Tumbler

Picture of Machine Magnetic Tumbler
100_1893.JPG

Notes about making the tumbler...

I machined my tumbler out of 3/4" thick HDPE. It machines nicely, and is non-ferrous, which is important for the tumbler. If you follow the technical drawing, you will make a duplicate of what I did with one exception. I changed the 0.25" dimension in the top-view to .375" to allow for less precise turning of the tumbler in order for it to line up with the bolt that unlocks the safe door. There is only one 0.25" dimension in the top-view.

I machined this part on my HF mini-lathe, and a Little Machine Shop Mini mill and made my tolerances within 0.004". The lathe is unnecessary if you buy 2" HDPE rod, instead of using 0.75" thick HDPE block like I did; I had it on hand.

To faithfully reproduce the part's dimensions for the holes you would need a forschner bit, or preferably a 1/4" end mill. That will give you the 90 degree profiles on the bottom of the various holes.

Step 3: Machine Magnetic Pin & Spring Housing

Picture of Machine Magnetic Pin & Spring Housing
Picture 7.png
100_1891.JPG

Notes about making the magnetic pin and spring housing...

I machined the Magnetic Pin & Spring Housing out of 3/4" thick HDPE on my Little Machine Shop Mini Mill. You can definitely reproduce this part on a good drill press with patience. Your tolerances will probably not be within 0.004", but you should be able to achieve close enough tolerances if you carefully mark, drill, and set your depth stop for your holes.

Standard wood drill bits should cut the plastic fine. However once again to faithfully reproduce the part's hole profiles you would need a forschner bit or 1/4" end mill.

Step 4: Machine Plexiglass Face Plate For Tumbler

Picture of Machine Plexiglass Face Plate For Tumbler
100_1879.JPG

Notes about making the face plate...

Using standard 0.093" plexiglass, or lexan machine the face plate part according to the technical specs. Once again, my tolerances were within 0.004". You really don't need to countersink the 4 holes on the outside. I just like the clean look of countersunk fasteners. You could definitely use a pan-head fastener.

You can definitely reproduce this part without much problem on your drill press.


Whoops...

You may notice that in the picture of the face plate I machined there is an extra hole in it when compared to the technical drawing. That was remnants from an earlier tumbler design where I had the two holes on the same radial path, which was later changed to different radial paths to prevent the locking pins from hanging up in the wrong hole. Instead of machining a new plate I simply melted some plastic and filled in the hole so it was smooth. Not beautiful, but very functional.

Step 5: Make The Repulsion and Attraction Locking Pins

Picture of Make The Repulsion and Attraction Locking Pins
Picture 9.png
100_1886.JPG
Picture 3.png
Screen shot 2011-11-17 at 12.26.23 PM.png

About the locking pins...

The lock utilizes two different types of locking pins to allow for a binary magnetic key. You could, in theory, make a much larger tumbler with more than two locking pins, which would allow for a very complex key. I would not recommend putting any more locking pins on a tumbler this size without redesigning the part. When placed closer in this design my magnets would interfere with each other and cause problem with activating or deactivating the pins. Maybe magnetic shielding of some sort would help. I couldn't immediately think of a way to do it without introducing more problems with the part.

If you get confused by the description refer to the two-stage technical drawing in this step to get a better idea of how they work. It shows what happens to the locking pins in and out of the presence of the magnetic key. Fortunately nails are cheap if you cut them to the wrong length.


Making the repulsion locking pins...

The repulsion locking pin is actually two pins. When the magnetic key is placed on the safe it repulses both pins away from the key. The repulsion of the two pins causes the point where they meet to line up with the top of the tumbler. This allows the tumbler to break the connection between the two so it can spin. When the key is not present the two pins' connect below the surface of the tumbler; thus not allowing the tumbler to spin.

Using heavy duty wire cutters, take two 3d 1.25" smooth shank flathead nails and cut them to the appropriate length according to your calculations from the technical drawings of the tumbler and magnetic pin and spring housing. File a nice beveled edge with a flat top on the end you just cut. This helps prevent the pins from hanging up in the mechanism. I determined the length of the pins by using a digital caliper. I wanted to be sure they were the right length and didn't want to go off the technical drawings. Because sometimes even with precision tools novices like me don't get it perfect.


Making the attraction locking pin...

For the attraction locking pin take one 3d 1.25" smooth shank flathead nail and cut it to length. When attracted by the key the attraction pin should be flush with the top of the tumbler. Be sure to include the thickness of the two 6mm x 1.5mm magnets that will attach to the flathead of each locking pin that ends up in the tumbler.

Once again I used my digital calipers to measure the length I needed, you can probably use the technical drawing of the tumbler to calculate the correct overall length of the locking pin.

Step 6: Assemble Magnetic Tumbler

Picture of Assemble Magnetic Tumbler
100_1888.JPG
100_1894.JPG
100_1895.JPG
100_1896.JPG

Why a tight fit is good, sort of...

As pictured below my two holes with magnets in them were machined to a tight fit for the 6mm x 1.5mm magnets. So I simply pressed the two magnets into each hole in place with my 1 ton arbor press. Although a vise with two pieces of wood could do the same thing; I think the arbor press was really overkill. I probably could have used my fingers, or the back of a screwdriver. I think sometimes I use certain tools as overkill to keep myself feeling good about having bought them:)

The other two holes pictured that are deeper are meant to hold your attraction/repulsion locking pins.


The pattern of polarity...

If you follow my pattern the polarity of the magnets facing out are as follows starting from the top going clockwise: North,South,North, and North. You may consider marking them with a permanent marker to keep track. Polarity is vital to the lock working properly. Also notice, I used two magnets in each hole and for each locking pin. note: you don't really need to know which side is north and which side is south, just be consistent.

Inserting the important stuff into the tumbler...

Insert all the magnets and repulsion/attraction locking pins in place, punch out two paper circles with a standard paper hole punch and place them over the repulsion and attraction pin holes. Then, being careful not to move the paper circles out of place, lay a piece of masking tape over the the two locking pin holes. flip the tumbler upside down and score along the the outer circumference of the tumbler to trim the excess masking tape off.


Label your stuff...

It would be wise to label which pin is your attraction pin, and which one is the repulsion pin in case you forget. The masking tape is enough because that side of the tumbler is sandwiched up against a piece of plastic. The tape is really more to help the locking pins stay put while assembling.

You may want to watch this video again to help you understand better what the end product will look like.


 

Step 7: Assemble Magnetic Pin & Spring Housing

Picture of Assemble Magnetic Pin & Spring Housing
100_1886.JPG
100_1890.JPG
Picture 8.png

Make sure you've made both halves of the repulsion pin...

To assemble the magnetic pin and spring housing, if you haven't already you will need to make the other side of the repulsion pin that goes in this assembly from another 3d smooth shank flathead nail. It will need to be long enough to protrude through the magnetic pin and spring housing and meet up flush with the other side of the face plate. This allows the two repulsion pin half's to slide off each other when the key is in place.


Install the magnetic pin and spring housing half of the repulsion pin...

Insert the above repulsion pin half into the magnetic pin and spring housing so that it will mate with the appropriate repulsion locking pin on the tumbler.


Make the adjustment screw assemblies...

You will make two adjustment screw assemblies that will allow you to fine tune the magnetic attraction/repulsion strength for the locking pins. The adjustment screws are two 1.25" zinc steel pan head machine bolts threaded into a 8-32 rivet nut that I compressed only enough to be a tight fit into the intended holes at the top of the assembly, while still being removable. The 8-32 nut pictured on the machine bolt is to lock the adjustment screws into position once the desired adjustments are made.

One adjustment screw assembly should be fitted with seven 6mm x 1.5mm grade 42 neodymium magnets and pressed into the hole on top of the magnetic pin and spring housing so that it will mate with the attraction locking pin side of the tumbler. The other adjustment screw assembly should have one 6mm x 1.5mm grade 42 neodymium magnet placed on the tip of the machine bolt so that it will repulse the other half of the repulsion locking pin that you already put in the magnetic pin and spring housing.

Step 8: Machine a Polarized Magnetic Key

Picture of Machine a Polarized Magnetic Key
100_1874.JPG
100_1873.JPG

Why magnets make this lock so special...

The binary magnetic key is what makes this combination lock a bit more special than just having a tumbler you spin with a magnet; because unless you know the appropriate pole combination, it won't deactivate the locking pins. So you can't use any old magnet to turn the tumbler. Also there is no way for someone to figure out the correct combination from feedback as to whether any given pin needs repulsed or attracted.

Of course one could use trial and error with all the different possible combinations, which isn't many with only two locking pins. Once again I wanted to prove my basic mechanisms would work. If you were to add multiple tumblers to the design or add more sets of magnetic locking pins that would require a larger number of magnets on the key you could of course increase the difficulty of figuring out the combination.

However I felt this design secure enough for my purposes. The more likely first obstacle someone would meet trying to unlock the safe would be to even know there is a safe behind the picture and that it uses a magnetic lock.


To make the key...

I used four 0.375" x 0.75" Neodymium Grade 50 magnets for the key. They are a bit powerful to be used as a free floating key, which I am sure could be remedied by using more powerful magnets in the tumbler and using weaker magnets in the key. But I figured that after I had built the set-up.

I machined the key out of 3/4" thick HDPE plastic. I drilled all the way through with a 3/8" end mill. If you were to use thicker plastic, or wood you could drill to depth and only have too stop them from coming out one side instead of two like I had to. Although I suppose you could avoid using anything to keep them in by drilling the holes to an interference fit with the right size drill bit; I did not have that drill bit.

If you have been following the polarity combination and direction that I have recommended for your lock make sure that when you insert the magnets into your key that you make sure the orientation is the same as the technical drawing, otherwise you will be putting the magnets in backwards.


Stop your magnets from popping out & don't scratch stuff...

I chose to put a piece of adhesive backed craft foam on one side and some clear packing tape on the other to prevent the magnets from slipping out of the key. So far it seems to be adequate, although in the future I may decide to do something more substantial for the covering, or make another key with interference fit holes for the magnets.

Whatever material you choose to make the key out of, be sure it won't scratch the plexiglass. You don't want to scratch up the beautiful surface that's in front of your picture; not very covert either. You could use glass for your picture frame to make it more difficult to scratch. Just be sure your magnets are not so strong that they break the glass when they attach to the lock. This is why I used plastic.


Design side notes for making the key...
I chose to remove most of the material to reduce the key to as small as I could. I did notice after I took the extra material away I had to change how I spun the key to ensure I kept it spinning around the center axis of the tumbler. The key was originally square and did not provide the same challenge of keeping it on center. Of course, the increased difficulty in using the key is a security measure as well. At first it took me several tries before I could actually work the lock so I could open the safe. But after 15-20 minutes of practicing with the safe open and noticing how my movements effected how the lock moved I got a technique down that allowed me to open it the first time just about every time.

Step 9: Wall Safe Construction


Choose a location...

Choose a natural location for a picture frame to be, and where you won't be competing with hidden electrical or other wiring. Of course the spot I choose happened to have tv and phone wiring in it but at least nothing dangerous.


Why water, electricity, natural gas, hammers, and power tools don't mix...

I should mention you need to really be careful when knocking holes in your walls; if you use too much force you may find an unsuspecting gas or water line that will give you an expensive and/or dangerous present of gushing water or natural gas. This is the be sure you know what you are doing part, or get someone who does.

I recommend not using a jig-saw to open the wall up until you have visually confirmed that no plumbing or wiring is behind the drywall. You should also once again be careful about how much force you use if you decided to use a hammer for this. I can't say the number of times I have found with a hammer unexpected surprises lurking in my home walls that I thought weren't supposed to be there. And when I say I can't... I mean I would be embarrassed to say exactly how many!


Make a hole...

Find the two studs on either side of your location, and very surgically with no more force than needed knock a hole through the wall in the center between the two studs on either side. You could use a stud finder, or if you're like me a really good guess.

Next proceed to carefully to take out the drywall in a line until you are about a half inch from the studs on either side. The point of doing this before we build the wall safe is so we can visually confirm what your stud spacing is. Mine were 16" centers. So that meant my wall safe was going to have an outside measurement of 14.5" minus a little to ensure an easy fit. Trust me! You don't want to assume the framers who built your house laid out the studs with precise spacing. I made my safe at first to the theoretical dimensions, and regretted the serious carpentry surgery I performed on the wall safe to make it fit into the 14.25" wide available space. I don't blame the builders, I blame my assumption.


Customize your safe to your needs and stud spacing...

Once you have your width measurement, draw out on paper the dimensions of what you want your safe to look like. I decided on a simple box with a false bottom that led to another storage space. If you choose to do that as well you should be carefull how large you make it because it is difficult to angle it down into the hole, and it can be difficult to angle the backing down past the walls of the secret storage compartment. I made mine 9" tall. This way I could theoretically put documents or other items I wanted to be extra safe. This extra space proved to be a little more difficult to execute then I originally thought, but I think the the coolness factor was worth it.


If you DO NOT want a secret storage compartment...

Build a box out of the 0.5" MDF that will fit as snug as possible without being too tight to wedge in between the two wall studs. For the backing I used 0.25" thick pre primed MDF. I fastened the box together with wood glue and dry wall screws for the backing, and wood glue and finish nails for the corners of the box. Your wall safe should be designed so that it will set flush with the drywall, on your side.


If you DO want a secret storage compartment...

Build a box as instructed above, except you will use a longer piece for the backing that will also back the secret compartment. Also, do not attach the bottom of the box to the backing. It will become the false floor that you will need to be able to remove.

Cut your safe walls for the secret compartment, and cut a triangle section out of the two uprights so that the peak of the triangle will be on the floor of the secret compartment. You should save your two triangle pieces you cut out from the lower safe section to screw into the studs in the secret compartment to provide full support for the false bottom. You have to cut out the triangles to allow you to slide the backing that is attached to the upper portion of the safe past the walls of the secret compartment.

Step 10: Picture Frame & Safe Door Construction & Assembly


The easy way out... maybe...

You could probably purchase a picture frame that would work, but I decided to make my own because I had scrap oak lying around and so I wouldn't need to set the safe door back into the wall so that it would not push the picture frame out from the wall increasing the gap between the two. The other problem with setting the safe back into the wall more was that the hinges I used didn't allow the clearance I needed to do that. So instead I made my own 11" x 14" frame that were the dimensions I needed it to be.


The picture frame construction...

I used a chop saw to cut to length and miter the 1.25" x 3/4" oak, which I then ran through a router table to route out a shelf that the plexiglass, picture, mat-board, and safe door would sit in and be flush with the back of the frame.

Another benefit of making your own frame is that on the hinge side of the frame you can route further to the edge of the frame so your cabinet hinges don't need as much clearance to open the picture safe. But you can still place your picture in the center and keep everything looking normal. Just make sure you leave enough thickness to attach the safe door to your frame.


Corner clamps and wood glue are your friend...

I used corner clamps to clamp the frame together and put wood glue between all the joints. Then I drilled some pilot holes to prevent splitting and hammered the eight 1.25" Furniture Finish Nails into each corner of the frame to keep it together. I used a punch to hammer the finish nails in past the surface of the wood, followed by wood filler and a good sanding. You can choose to stain your frame at this juncture; I used a oil based stain followed by a clear poly urethane coat. Although you may want to wait until after you have installed the safe and door to avoid damaging the finish.


The safe door construction...

For the safe door, I constructed it out of 3/4" thick birch plywood I had available. You could use pine board or mdf. I measured my frame and cut the door so it would fit exactly inside of the frame except for the side where the locking bolt slides back and forth to lock and unlock the safe. On that side, I left a small gap so that I could have my plumbers tape act as a latch for the safe to hold onto the bolt when it was extended to prevent the door from opening.


Drilling the holes for the cabinet hinges...

Drill the appropriate size hole with a forschner bit for the two cabinet hinges so that the holes are on the absolute edge of the plywood door. The closer you get to the edge of the safe door the less clearance your hinges need to provide for the door to open fully.

You may notice in the pictures that my holes are not on the edge. I had messed up on my measurements for the door size and location for drilling the holes. Fortunately, these two mistakes canceled each other out because I simply trimmed off the excess on the table saw so that the holes were on the edge. If you look at pictures of the door opened when the safe is installed you will see this change.


Drilling the holes for the lock...

Use a 2 1/8" Forschner bit to drill out a hole for the magnetic lock. It should be just deep enough to accommodate the tumbler and a thin piece of plastic and few thousandths of an inch gap that will help reduce friction on the tumbler so it can spin freely. It's key that the tumbler is allowed to spin freely with no hangups.

The hole for the tumbler should be placed far enough in on the door. So when the locking bolt is extended it will slide through the a hole on the plumber's tape latch, and when it is retracted be flush with the edge of the birch plywood. You may notice that the forschner bit's pilot point will penetrate through the plywood partially. This is okay; it will be covered up by the thin plastic on the inside of the tumbler hole and a picture and plexiglass on the outside. Just make sure to de-bur the hole with an exacto knife so it won't interfere with the tumbler.

Drill a hole through the side of the door closest to the hole for the tumbler. This will house the aluminum tube that will allow for your 2.5" long finish nail that acts as the bolt for the catch to slide freely. The hole should be be a tight fit on the piece of the aluminum tube, so it won't move around, or slide out. Glue can be used if necessary to ensure a secure fit.


Assembling the safe door...

Using equivalent spacers that are equal to the thickness of the plexiglass, mat-board, and picture of choice; line the inside shelf of the picture frame with the spacers. Next place the plywood door on top of the spacers. Carefully drill four angled pilot holes through exposed backside of the safe door into the picture frame, but don't go all the way through to the outside of your picture frame. Remove the spacers and replace them for the plexiglass, mat-board, and awesome picture of you and your son building a snow fort (or other great picture.) Using four dry wall screws or other short wood screws attach the frame to your safe door.

Step 11: Installing Magnetic Combination Lock


Reduce friction...

Cut out a thin plastic disc from scrap packaging, or in my case a junk calendar that will fit in the bottom of the hole meant for the tumbler. This reduces friction on the tumbler. A can of WD-40 happened to be the right size for the disc, so I used that as a templateto trace a circle and cut it out with a pair of scissors. Place the plastic circle in the bottom of the hole. With your fully assembled tumbler, place it slot side down (the slot on the tumbler that the bolt will slide into to allow the door to open when unlocked.)


Assemble the locking bolt assembly...

Insert a 2.5" long 8d smooth shank finish nail with brad head into the aluminum tube. Cut the aluminum tube to be slightly shorter than the length of the hole we drilled for it. The aluminum tube needs to be flush with the birch plywood edge. And the tube should be set into the hole on the tumbler side to allow the brad head of the locking bolt to extend sit in the hole out of the way of the tumbler when the locking bolt is extended to avoid interfering with the spinning of the tumbler.

Also the brad head should not be able to go through the aluminum tube.

Once the aluminum tube is cut to length, insert the finish nail that will act as the locking bolt into one end of the tube. Make sure it slids freely, if not use sand paper to debur the nail untill it does, or try another. Insert the aluminum tube and nail into the small hole on the edge of the plywood until it is flush.


Fasten the face plate...

Place your face plate over the tumbler with the two holes meant for the locking pins that stop the tumbler from turning on the top side of the door, and insert an uncompressed 6-32 aluminum rivet nut in through the center hole on the face plate and into the tumbler. Ensure that the tumbler can spin freely. Screw the face plate to the back of the door with the tumbler trapped inside.

You may choose to test whether your key can slide the bolt back and forth at this point. The side of my key in between two of the magnets worked best.


Fasten the magnetic pin and spring housing assembly...

Next, mount the magnetic pin and spring housing so that the appropriate repulsion/attraction locking pins match with the two holes in the face plate and tumbler when all rotated properly. Use your key to line up the tumbler if you need to.


Fasten the latch...

Attach a piece of bent plumber's tape to the inside of the safe wall so that when the door closes it lines up with the bolt and will catch on the bolt when extended.


Ensure the locking bolt can extend and retract enough...

If the locking bolt does not extend far enough to allow the tumbler to spin when attraction/repulsion locking pins are disengaged; drill out a hole in the side of the picture frame. This will allow the bolt to extend to the point where it will allow the tumbler to spin without interference.

Step 12: Wall Safe Installation & Finishing Touches


If you haven't already, cut out the section of drywall where you want your safe to go...

I started with a hammer, then used a level and pencil to mark the section I needed to cut out. Then after taping the wiring to one side I used a jig saw to cut on the lines, making sure to stop before I got close to the wires and move them to the other side. These weren't electrical, just cable and phone. Clean up the edges with a utility knife. Remember what i said about the dangers of opening up walls with power tools and hammers.


Install secret compartment walls and floor assembly...

insert the bottom portion of the secret compartment being sure not to let it fall into the deep recesses of your wall. Fasten each side to a stud with some wood screws.


Install upper portion of wall safe, and backing...

Next take the upper portion that is attached to your backing and insert at an angle into the wall. If you measured and did your math right, everything should fit nicely. Fasten it to the studs with a few screws. Take the two triangle pieces you saved and fasten them in the secret compartment area so the false floor can have even support.


Seal seams up...

Using drywall compound, or if you did a good job cutting your rectangle out, caulk and clean up the edges around the safe so it looks seamless. I used a damp rag to wipe excess drywall compound off the texturing of the painted wall, so I wouldn't need to repaint. After that dries


Paint the safe...

Mask off the wall around your safe. Using your favorite color, paint the inside of your safe with the false floor only partially inserted. You don't want it sticking to the backing. I did two coats of paint. Before the paint dries carefully remove the masking tape. If you wait until after it dries you will need to use an exacto knife or razor to score along the edges so paint isn't pulled up. I did not bother painting the secret compartment


Mounting the safe door and picture frame...

Mount the safe door onto the inside of the safe like you would any other similar cabinet door installation with hidden hinges.

Yay, you did it! Now please read the next step before you go locking your valuables inside...

Step 13: Learn How To Use Your Key Before You Lock Important Things Inside


A bird in the hand is better than a lot of valuables in a sealed safe...

Regardless of how easy you could break into the safe with a crow bar, I am assuming you don't want to if you went through the trouble of building one. If you haven't recorded your key polarization combinations down on paper and you lose your key, you may be breaking out the crow bar to get into the safe. Keep that in mind.


Practice makes perfect, or at least most of the time...

This lock requires practice to unlock, like a lot of spinning combination locks do. So don't lock the safe until you are sure exactly how to unlock it. I suggest practicing with the safe door open. Go through the whole process multiple times until you can do it the first time every time. It took me 15-20 minutes of playing around with the safe door while it was open before I got it down. As you practice watch how your movements with the key effect the mechanism. Once you can do it enough to feel comfortable locking up important items enjoy your awesome hidden wall safe!


Thanks, for listening...

Thanks for your patience with me. I hope it inspires you to make your own:) and to take the ideas from the shoulders of the past and use them to make the technology of today the amazing of tomorrow!

Thanks for all your support!

Andrew Jorgensen
1-40 of 43Next »
4B-24N2 months ago

where to buy

claudg19503 years ago
Great idea and great work!!
To further simplify the design: perhaps even simpler than a sliding lock could be a pivoting lock. The piece would only need a bolt as axis.
A source for free neodynium magnets: an old computer hard disk.
pastprimitive (author)  claudg19503 years ago
Thanks! I am curious as to what you imagine the pivoting lock looks like? I'm not quite able to picture what it would look like.

I am currently working on a simplified version that can be easily made with really basic tools. I will be posting another instructable on it. And your idea sounds like an intriguing path to follow.
My explanation wasn't clear. Sorry.
I am attaching a sketch which will show you that my idea, after all, was offensively simple. Inside the box, a magnet is permanently attached to the pivoting bar. Then, from the outside, you glide your hand held magnet in a curve (see arrow) which will move the bar away from the rest, thus unlocking the box.
I'm sure you could improve a lot on that (for instance, adding a second pivoting bar which would prevent the main one from pivoting unless you displace that one first...)
My point is that there should be a lot less friction with a pivoting than with a sliding bar. All the best.
Pivoting magnetic lock.JPG
pastprimitive (author)  claudg19503 years ago
I see. I actually had something completely different in my head when you said pivoting arm. This makes much more sense. Has the advantage of being able to place the magnets so that you can get a force multiplier that would make it easier for a less powerful magnet to move the bar.

I am working on the simplified version of the lock, and I just might incorporate this idea of a pivoting locking bar in the design. Thanks for expanding my through horizons. Very clear picture.
I'm glad I saw these comments, thanks for the simplification idea. Just posting constructive comments like these helps people think outside the current idea to keep it evolving. I love it!

Is there any new update or post with a pivoting bar?
I will definitely have to try this.
noahh3 years ago
Very cool project. It would be cool if someone with a 3D printer posted files on Thingiverse allowing others to print the parts rather than having to machine them, which would make it easier for people to make something cool like this.
pastprimitive (author)  noahh3 years ago
I would love to make it easier for people to make. I have all the parts already drafted in a cad program. If you told me what format they need to be in I would gladly post them? Or is it a proprietary format unique to 3d printers?

Thanks for the compliments!
I don't know a whole lot about 3D printing, but a bit of research shows that STL formatting seems to be common. Thingiverse has a list of file types that work.
pastprimitive (author)  noahh3 years ago
Well I will take a look at it and get those files posted.
do u know wear u can find 3d 1.25 smooth shank flathead nail?
pastprimitive (author)  StReEtCrUsH353 years ago
It should be a standard nail size carried by most hardware stores. I got mine from Home Depot. Here's a link.

http://www.homedepot.com/Tools-Hardware-Hardware-Fasteners-Fasteners-Nails-Box-Nails/h_d1/N-5yc1vZbua5/R-202308634/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

The one confusing thin I noticed is they don't carry it online under it's penny designation which is "3d" they carry it as a 14 gauge nail.

Hope this helps.
wat are the dimensions for this
awesome thanks
like wats the length for each line and stuff like that cuz im tryin to replicate it
pastprimitive (author)  StReEtCrUsH353 years ago
Originally I machined my key by using the technical drawing of the tumbler from step two, and placing the four holes so they lined up with the corresponding holes on the tumbler technical drawing.

However, I went ahead and updated step 8 of the instructable with a technical drawing I drew up of the key for you, and other future readers. I wanted to make it a little simpler to machine; with less work on the readers part to figure out the dims.
Thetis3 years ago
It might be the picture, but the holes in the plexiglas look pretty rough with darkened edges. Plexiglas (Perspex to us Brits) can machine really nicely to a great finish, but only at low speed with good sharp tools and a gentle approach. Higher speeds heat it up very quickly and it melts and burns, which is what looks like happened here.

Picky I know, but so easy to avoid...
pastprimitive (author)  Thetis3 years ago
Picky is fine, I am glad you pointed it out. Especially since you had advice on how to do it better.

While the holes don't have dark edges in real life (just in the picture) they definitely are rough. I am a self-taught machinist. Everything I know I learned online, or taught myself through trial and error. There are many techniques and materials I am just not well educated in yet. Perspex (Plexiglass) is one of those.

I ran it at a higher speed because in the past I have cracked workpieces When running at lower speeds. But I am assuming that is my own bad machining/clamping technique combined with my more likely than not dull cutters.

I am going to go try machining some more plexiglass and follow your instructions to see if I can get cleaner surface finish. Do you have an rpm suggestion to try cutting at?

Thanks.
Now you are asking! I have to confess that I'm not terribly scientific about speeds, I tend to just go with what feels right. Which is no doubt why I've melted so much perspex!

The rpm to use is, of course, directly related to the nature of the job you are undertaking and the main thing to bear in mind is keeping the temperature down. Recommended speeds are usually given as a linear speed (eg, metres per minute) which you then have to translate to the appropriate rpm and feed rate. As an example, I'd be choosing a speed at something below 200rpm to drill a hole, and probably well below that to drill a deep hole (because the heat builds up down there), with lots of pecking to let things cool down.

However, blunt or inappropriate tools, or trying to feed too fast, or too slowly will also increase heat production so it is difficult to be precise. Nothing improves your work so much as a good, sharp, appropriate tool. If you are having problems with cracking have a go at altering the rake on the drill - it takes a few seconds with a stone slip, or you can buy drills optimised for drilling soft materials.

This document has lots of useful information: http://www.theplasticshop.co.uk/plastic_technical_data_sheets/working_with_perspex_manual.pdf
pastprimitive (author)  Thetis3 years ago
Thanks for all this good information. Especially with the links. Won't complain about somebody willing to help me get better. I browsed the pdf you sent the link to and what an awesome document that was. Those are the kind of informational packets a self-taught machinist lives to find.

I remember reading about feed speeds in milling. But I have never paid much attention to that because since my mill is a manual turned mill; a Sieg SX2 to be precise. In the past It's always seemed quite obvious what the feed speed should be because you got lot's of feed back through the hand wheel on how well it was cutting. If you fed it too quickly and chatter would increase. Of course plastic is not as obvious because it is so soft.

Thanks again.
bogie46463 years ago
This is an awesome instructable, great work. I've been currently trying to think of something to build based on a combination of instructables that I've seen and now I've got another aspect that I want to put into it.

Whenever I figure out my final design and build it, everyone that has given me inspiration will definitely be credited. The unique ideas in instructables like these are what make this site so awesome.
pastprimitive (author)  bogie46463 years ago
Thanks. I am glad I could be of some assistance.
jab05923 years ago
This is really awesome! I am thinking about making one and to hide the key, I was going to imbed it into an ornament, kept local to the safe. This allows boths parts of the device to remain secret, covert and more fun :D
Good job man!
pastprimitive (author)  jab05923 years ago
Thanks. I love your idea of embedding it into an ornament.
whiteoakart3 years ago
This is really impressive. As a product designer and benchtop engineer, I love this sort of thing. I don't imagine a need to build anything this complex myself, but I could see using the ideas to make a hidden slider lock as some of the other comments have mentioned.
pastprimitive (author)  whiteoakart3 years ago
Thanks for a generous compliment. Sounds like another vote for getting the simplified version posted.
Stevos3 years ago
awesome!
pastprimitive (author)  Stevos3 years ago
Thanks!
LifeWarrior3 years ago
Very cool idea! Wouldn't be easy for those without the tools but still cool! I love the type of extreme ibles, because they are inspiring. My first thought was how could the average guy with a few hand tools do the same thing or something similar, so for a part 2 a simple magnetic slide lock (thinking of a flat barrel lock of sorts), Granted it would be as secure as a keyed combo lock but then again it's already hidden by the picture frame, but still very bada**. great job!
pastprimitive (author)  LifeWarrior3 years ago
I agree that it would be awesome to make another version of the magnetic lock that would be a simple magnetic slide lock that did not require a tumbler. It would be awesomely easy for someone to make with simple hand tools. Although the security would not be quite as good as the combination lock, but still provide the benefit of a hidden locking mechanism that required a specific key.

In fact while I was thinking through the different designs for the magnetic lock a slide lock was high on my list of candidates to prototype. But I decided to go for the combination lock design; because it had the alluring feature of still being very difficult to unlock even if someone found the key. I geeked out over the coolness of redundant security features. But I think I need to post another instructable for the slide lock version as well.
The combo lock is definitely a contender for the contest, Some of my favorites that I'll actually try to recreate though are the ones that are useful this one fit's the bill, however I probably won't get lock elaborate like the combo, that's one reason I suggested a follow up with a basic locking mech. like a slide. My thought is for my situation if anyone even finds it or a thief realizes it's there, probably nothing I can build by hand to keep them out of it. However for keeping teens and curious family members out of it the combo lock would be slick to have. I've even considered an infrared led in the frame to trip a servo to unlock but again way too much work for a hiding space, however I've considered it for a small wall safe I have. But abandoned it because of a hotel door lock that uses a magnetic strip card (acquired from a junk pile) that I'm trying to figure out.

Yes I'd love to see the slide lock though, I was already looking around my shop for materials after seeing this. Very cool take on the wall hiders, thanks!
pastprimitive (author)  LifeWarrior3 years ago
Thanks for your confidence. I hope it's a contender as well. Teens and curious family members is exactly what I thought this would excel at. A determined enough individual can break through just about anything. But keeping honest people honest is usually a much easier process. Although I would like to make another safe that is built from steel for the body, and door. But I would use stainless steel for the door so it would not interfere with the magnetic lock. Since stainless would not interfere with the magnetic lock device like regular steel would.

I will follow up on your suggestion and put out an instructable on how to build a simpler version that doesn't require the use of precision tools. I think it's a great idea, and a natural progression of making it more accessible.
This is way cool. I would also like to see an instructable for the simpler version. I have an old lighter display I'm trying to find a way to lock. It already has a lock but no key and I don't want to be in position of having to pick it each time I need to get into it. I think the slide lock might just fill the bill.
pastprimitive (author)  paqrat3 years ago
Well, I'll do my best to get the simpler version done as soon as possible.
Good instructable but maintain good distance of your credit cards when handling Neodymium magnets!
pastprimitive (author)  Rudiger Schulz3 years ago
Thanks. Good point about keeping credit card away.
Tkdwn3 years ago
Love it!
Tnx!
mikeasaurus3 years ago
awesome idea and loads of detail, thanks!
pastprimitive (author)  mikeasaurus3 years ago
Your welcome!
1-40 of 43Next »