Introduction: All My Hearts, Combination Puzzle Box
I had so much fun, and got such a great response from the Instructables community on my Wooden Keep Sake Box that I wanted to try and make a truly unique puzzle box. One that would incorporate some more rare earth magnets, after all I did have a lot of magnets left over that I needed to find a use for.
During this build I had a general idea of how the entire locking system might work, but the final design and construction had several modifications along the way. Let's just say.. it might have taken a little longer than I had anticipated ! Again !!
I was thinking of making two boxes, one as a gift to each of my grown daughters. So during this instructable you might see multiples of the same piece in some of the photos. Please also take note that the only metal parts in this box are the magnets, all other connections are made with glue and dowels.
Please enjoy the videos, one shows the outside of how the box is opened and other one shows you what happens inside.
So Sorry , if there seems to be a problem with the video. Vimeo was having some issues but please come back later to see the videos :-( Thanks
The steps to open the box.
1. Press down on the right side of the center heart and slide the top right heart up.
2. Remove the center heart and place in the correct position on the magnets to the right of the main heart.
3. Press the right side of the heart down unlocking a magnetic pin and swing the lower hearts out of the way.
4. Use the top left heart like a combination lock ( 3 digit ones like the ones had in high school, (40+ years ago for some of us).
5. Once the combination is met, slide the apparently fixed handle to the left,- unlocking the lid.
Hearts - a variety of unique wood was used - Bubinga - which sounds like bazinga :-) , Ash, Tigerwood and Yellow Cedar Birdseye
Face of the box and bottom - 5 mm (1/4'' ) Mdf with Teak Veneer on both sides and a Bubinga, Black Walnut and Maple inlay
Box sides - Cherry with a Bubinga, Black Walnut and Maple inlay
Wood hinges and Corners - Bubinga
All parts of the locking mechanism - Beech
6 mm x 3 mm, 10 mm x 5 mm and 8 mm x 3 mm rare earth magnets.
Take caution when working with rare earth magnets!! They are very strong and can snap together quite violently (ouch) !
9.5 mm ( 3/8'' ) maple dowel for the pins
6 mm ( 1/4'' ) hardwood dowel for the hinges
Spray contact cement for gluing the veneer to the mdf
Water based clear finish, foam brushes
Planer, table saw , chop saw, drill press, drum sander, plunge router, drill, scroll saw, dremel, sander
drill bits , hole saws, sand paper, glue, tape, clamps,
Oh, and a stupid crazy amount of extra time
Step 1: What Happens Inside With Each Move Outside
I've documented the steps on both the picture ( notes on the picture ) as well as in the steps below
- ( pic. 1a ) heart in lock position
- ( pic. 1b ) Inside in lock position
- ( pic. 2a ) right side of center heart pressed down to release magnetic pin allowing top right heart to slide up
- ( pic. 2b ) magnetic locking pin released allows upper right heart to slide up
- ( pic. 3a ) center heart can now be removed and placed on magnets to the right
- ( pic. 3b ) heart is rotated 90 degrees
- ( pic. 3c ) right side of heart is pressed releasing a second magnetic pin allowing the lower hearts to swing down
- ( pic. 3d ) magnetic pin allows locking arm #1 to swing away allowing combination lock to turn
- ( pic. 4a ) turn top left hand heart clockwise to engage all 3 tumblers.stop at first number of the combination
- ( pic. 4b ) turn heart counterclockwise one whole turn and stop at second number in the combination
- ( pic. 4c ) turn clockwise to the last number in the combination
- ( pic. 4d )by turning the heart to the right combination all three notches in the disks line up
- ( pic. 4e ) close up of all three tumblers lining up
- ( pic. 5a ) the handle can now slide to the right because locking arm #2 can go into tumbler
- ( pic. 5b ) close up of locking arm #2 lining up with tumblers
- ( pic. 5c ) when the locking arm #2 is allowed to engage the notches in the tumbler the handle is free to move and unlock the box
Step 2: Making of the 3d Marquetry Heart
Start by drawing your design and determine how it's going to fit together. It's easiest to start the design with the your most centered piece, in this case, the small reddish Bubinga heart.
Draw out your heart and then cut it out on a scroll saw. Using a dremel with a small sanding drum smooth the edges but don't contour any edges yet. Place this heart on top of your next adjoining piece of wood, trace the side and cut the next one. Repeat until all your pieces fit together as tightly as possible, like a puzzle.
Be sure to use different thicknesses of wood to create depth. Take your time because this will show in the end. Once you are happy with the fit it's time to contour the edges to give the effect of balloon hearts. Use your dremmel, sand paper files or whatever works for you to produce rounded edges.
Once all the pieces are sanded ( to at least 220 grit ) take the pieces that require gluing together and using a small amount of yellow glue, glue between the joints and tape to dry.
To determine the exact location for the magnets and dowels on the back of the heart pieces, tape the entire heart together and place onto your template piece then tape it in place. Mark and drill holes for your magnets and dowels into the back of the various heart pieces.
Step 3: Drawings and Dimensions
This section has a few drawings with dimensions
- drawing of the box, with dimensions
- drawing showing the magnet and hole locations in the top
- the heart on 6 mm (1/4'' ) graph paper
- parts for the locking mechanism on 6 mm (1/4'' ) graph paper
Step 4: Box Lid
Cut a piece of 6 mm ( 1/4'' ) mdf and a piece of wood veneer slightly larger than your finished size. Using a spray contact adhesive glue the veneer to the mdf.
This will be the inside of the lid of the box. Cut this piece to size and then cut another piece of mdf exactly the same size ( this 2nd piece will be used as a template for all of your drilling and the locations of the pieces - basically your road map for the box ).
Tape the two pieces of mdf together with the veneer side in the middle. Start laying out the heart on the piece with the veneer ( future top of box ), determining the location of the holes and small dado. Then using a 9 mm ( 11/32 '') collet for your plunge router and a 6 mm (1/4'' ) straight cut router bit, make jig to router a small dado through the two layers of mdf. what ever you do to your top piece happens to your template and vise versa.
On your drill press drill 9.5 mm ( 3/8'' ) holes for the combination lock and swing pin through the two pieces.
Step 5: Magnetic Locking Pins for Slider
Starting with 5 mm ( 3/16 '' ) thick stock by 42 mm ( 1 11/16'' ) wide solid stock, and using the same router set up that you used on the top, router a dado the same length in the solid stock 6 mm ( 1/4 '' ) from the edge. Router a second piece except with a dado 11 mm ( 7/16'' ) less. Both pieces will eventually be cut to 76 mm ( 3'') long after further machining.
The one piece with the longer dado will be glued to the bottom of the lid and matched up with the dado in the top. Position the piece in line with the dado in the top using a piece of wood to line them up on the bottom side ( template piece ) drill a 5.5 mm ( 13/64 '') hole from top right through this piece ( this will be the hole for the lock pin ). On the underside around the outside of this hole drill four 6 mm ( 15/64'' ) holes 3 mm deep for the 6 mm x 3 mm magnets. Now place a 10 mm x 5 mm magnet in the center hole.
This is the cool part, the 10 mm magnet will self center on the piece and will move to one side or the other when pulled from the force of another magnet ( The 8 mm x 3 mm magnet in the center heart ), but it will always return to the center when that magnetic force is removed, thus acting as a lock pin. Don't ask me how long it took to figure out this little bit of wisdom.
The second piece ( with the shorter dado ) will slide in conduction with the top right hand heart by means of a pin that connects the two.
There is a second magnetic pin to unlock the swing arm #2 also glued to the underside of the lid. It has the same magnet configuration, and can be seen in future pictures.
Step 6: Parts Required for the Locking Mechanism
The pictures above show all of the pieces required on a sheet of 6 mm ( 1/4'' ) graph paper with notes on each picture with regards to hole sizes shapes and sizes.
The 5th picture includes the pieces that are fixed to the lid.
Step 7: Tumbler for Combination Lock
There are three tumblers, two of which spin freely and the thicker one is connected to the top left hand heart by a dowel through the top. Using a 60 mm ( 2 1/4 '') holes saw, cut 2 disks out of 3 mm ( 1/ 8'' ) material and one out of 5 mm ( 3/16'' ) material.
You also require 5 washers- four 3 mm (1/8'' ) thick, one 5 mm ( 3/16'' ) thick all by 28 mm (1 1/8'' ) diameter. Using a 32 mm (1 1/4'' ) hole saw cut your washer and then stack on a piece of 1/4'' all thread with a couple of nuts, place in your drill press and sand all together. Use this same method for the larger disks. Re drill the center of your washers and tumblers with a 9.5 mm ( 3/8'' ) bit that will fit the maple dowels.
The notches in each tumbler were cut in once the combination was decided, for more information on how wooden combination locks work please check YouTube.`
The stiffener for the tumbler dowel is a block with an arm that extends out over the tumblers and is held to the top of the box with two dowels.
Step 8: Magnetic Repulsion Tension Blocks
There are plenty of videos on wooden combination locks, the only difference is that they all have vertical tumblers that will stay in position after they are in the correct position .
I had to come up with some way of holding the tumblers in position in the horizontal position, so, by using the ability of magnets to repulse each other they could act as a tensioner on the tumblers.
The tension blocks are two 6 mm ( 1/4'' ) thick by 25 mm ( 1 '' ) wide and 32 mm ( 1 1/4 '' ) long pieces that ride inside of a three sided box. Inside each box there are two fixed magnets which match up with the magnets in the tension blocks ( magnetic polarity N to N or S to S ).
The tension block box is then glued on to the box lid and these tension blocks put just enough pressure on the tumblers to hold them from moving once the combination is met.
Step 9: Wooden Hinges
Start with 8 mm ( 3/8 '' ) thick x 40 mm ( 1 9/16 '' ) wide stock cut to 76 mm ( 3 '' ) long pieces. Using a 4 mm ( 3/16'' ) round over bit round the ends of each piece .
Using your drill press and a 6 mm ( 1/4 '' ) brad point bit drill drill a hole 4 mm ( 3/16 '' ) in from the end right through the piece ( go slow so that your bit does not wander ).Tape together all your pieces into a bundle.
Set up your table saw with a 8 mm ( 5/16 '' ) dado blade. Using a cross cut sled and a 8 mm x 8 mm stop ( 5/16'' x 5/16'' ) cut dados 9 mm ( 11/32 '' ) high into your bundle. Cut the entire bundle in half, then using a 6 mm (1/4 '' ) hardwood dowel as a hinge pin put the hinges together.
The hinges will be fastened to the box with 6 mm ( 1/4'' ) connection dowels. Make up a jig that holds the hinges for drilling them on the drill press and can later be clamped to the box to drill the matching holes for the connecting dowels.
After your box is assembled ( sides and top, the bottom still loose ) and the lid has been cut, clamp your box back together. Then using the the jig you made up for the hinges, clamp it to the box with a scrap piece on the inside of the box and drill your holes for the connection dowels in the lid and on the side of the box.
When it comes time for assembly, disassemble the hinges by removing the hinge pin. Cut your dowels to the correct length and glue them into the holes on the side and the lid, apply a small amount of glue to the hinge and clamp in place.
Step 10: Making Decorative Veneer
Carefully cut layers of veneer 430 mm ( 17'' ) long 60 mm ( 2 1/2'' ) wide and plane down to 3 mm ( 1/8'' ) thick.
Tip : When running thin strips through a planer, use some two sided tape on the leading edge and stick the piece to be planed to a piece of mdf and run it through the planer together. The tape holds the strip from wanting to pull up into planer blades.
Glue and clamp the layers of veneer together to make up a solid block ( let dry overnight )
Joint one edge of the block and then set up your table saw with a fine tooth sharp blade and set the fence to 1 mm (1/16'' ), raise the blade up thru a piece of mdf taped or clamped to table surface this will give you zero clearance around the blade. Make up a push stick that will hold your entire piece down and rip thin strips off your glued up block, roughly the thickness of your veneer. Don't forget to save a piece 32 mm ( 1'' ) wide to use in your handle.
When it comes time to make up the veneer for the top start with a full size piece of veneer. By cutting all of the pieces out of one piece you can maintain the grain pattern. Cut the two outside strips, then cross cut the two ends on the center piece. Then take two rips off the top and bottom of the center panel equal to the width of the veneer inlay.
Cut your decorative veneer to fit tightly around your center piece, then fit your outer pieces of veneer around that and tape them together on the face.
After all the machining has been done on the top and the magnets have been installed ( use your template piece to determine the magnet locations and polarity ) place small pieces of dowel in the holes to prevent spraying contact into the holes. Apply spray contact to the back of both the veneer and the lid, remove the dowels and apply the veneer. drill and cut out the holes that go through the top.
Step 11: Box Construction
The sides of the box are constructed of 8 mm ( 5/16 '') thick by 90 mm ( 3 1/2 '' ) wide strips. The top and bottoms of the sides have a 5 mm ( 3/16'' ) deep rabbet the height equal to the thickness of the top and bottom panels of the box.
On the outside of these strips set up a dado blade equal to the width of the decorative veneer strips and as deep as the veneer is thick. Set the fence 6 mm from the blade and run dados on all four pieces. Glue a strip of your decorative veneer into each piece. Re cut the top piece and the bottom of the box to the same size.
The bottom is made the same as the top, two pieces of veneer glued to a piece of 6 mm ( 1/4'' ) mdf.
Cut the sides to fit around the top with 45 degree cuts on the corners. Once you have the sides cut to size sand the inside faces of the box, the sides and the bottom of the lid to 220 grit. Glue the top and the four sides together using tape to pull it all together. Cut and glue some 45 degree wedges for the inside corners. Do not glue the bottom in yet.
Once the box is dry set the fence to 59 mm ( 2 5/16'' ) and carefully cut all around the sides of the box, releasing the top. Sand both faces of the cut and lightly break the edges on both pieces.
Clamp the two pieces together and down to your work bench so you can router a slot ( using the same router set up and a jig ) to make a 105 mm (4 1/8'' ) slot down the top of your decorative veneer strip right in the middle of the box. This slot is for the handle to slide in.
Using a piece of your decorative strip 196 mm ( 7 3/4'' ) long by 25 mm ( 1 '') cut a tenon on one side that fits into the slot for the handle , make it 12 mm shorter on the left side to it allow it to slide and unlock the box. The tenon should be slightly wider than the side thickness so that when the lock bar is attached it can slide freely.
Step 12: Locking Pin, Magnetic Pins and Corner Pieces
The lid locking bar is fastened to the handle by means of two 3 mm (1/8'' ) dowels. Once the locking arm #2 is in position and the lid locking bar is temporarily attached to the handle the three 5 mm ( 1/4'' ) connecting pins can be positioned and installed on the two bars linking the two together.
The magnetic pin locks and the housing for the tension pins can all be permanently glued to the underside of the top prior to finishing.
The decorative corner pieces ( 3 mm ( 1/8 '' ) thick ) are glued on and clamped in place after the face of the box is sanded.
Step 13: Finishing and Assemble
The entire box and all its pieces should be disassembled and sanded to 220 grit sand paper, paying close attention to breaking all the edges.
I applied two coats of a clear water based lacquer finish with 30 degree sheen, and lightly sanded with a fine sanding sponge between coats. For the application I used foam brushes.
After all of the parts are completely dry it's time to reassemble the box. Start with applying some self adhesive felt to the underside of all of the heart pieces on the top. This will stop all of the moving pieces from scratching up the top.Then assemble all of the parts and pieces for the locking mechanism that connect up to the hearts on the top. Lightly rub some candle wax on any of the moving parts as a bit of lubricant.
At this point you would have assembled and disassembled so many times you know what needs to be glued and what does not.
After the entire lid assembly is back together you can glue the bottom into the box and reinstall the hinge pins, ( I did not glue the hinge pins in just in case something goes wrong with the lock ) Looking at it you can not tell that the pins are removable.
Step 14: Conclusion
All I can say is that this whole project was a real head scratcher from start to finish, and there were times I contemplated putting the whole thing on the shelf and revisiting it NEVER! I'm proud that I stuck with it because I think the finished box turned out amazing ! It makes me happy to think that it will be with my daughters long after I'm gone and maybe passed on to their kids. Hopefully some one will remember to write the combination down somewhere along the way.
I know that there may not be a lot of people out there that will attempt a project like this. My hope is that you enjoyed the build and might be able to take parts of what I've done and incorporate them into something else to make it your own.
Stay home if you can, create and be safe.
Grand Prize in the