Wooden Keep Sake Box With 4 Digit Magnetic Combination

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Introduction: Wooden Keep Sake Box With 4 Digit Magnetic Combination

About: Just an average guy. husband, father of four, grandpa, civil engineer turned cabinetmaker, jack of all trades master a few. Enjoys, golf, curling, woodworking, creativity & making things.

I've always had a fascination with puzzle boxes, wooden locks and magnets, so when the magnet contest was announced I thought I'd incorporate all three into one. I wanted to come up with a lock with a changeable combination and decided to use four tumblers with each one containing nine possible magnet locations, that gives a total of 6561 possible combinations to unlock the lid!

The basic premise of the lock box goes like this; moving the apparently fixed handles on the ends forward causes 6 rare earth magnets on wooden pins to pop out, then using those magnets on the lid to slide the tumblers inside of the top ( also containing magnets ) to specific number locations. Once the correct combination is met, the main locking bolt is free to move ( by using another magnet ) which unlocks the box and frees the lid to pop open (using the touch-latch pin).

I used millimeters for most of my measurements because when working on something this small it is far easier to mark out,( and being a Canadian were suppose to be on the metric system eh ;-) but I included the imperial measurements as well.

Take caution when working with rare earth magnets!! They are very strong and can snap together quite violently (ouch) !

Please be sure to keep them away from young children, they are not a toy and are very dangerous if swallowed!!

Supplies

32- 5 mm x 5 mm rare earth magnets ( Amazon )

6 - 8 mm x 3 mm rare earth magnets ( Amazon )

five minute epoxy, masking tape, carpenters glue, wipe on finish

solid - maple, black walnut and beech

# 6 x 1'' pan head screws , # 6 x 3/4'' pan head screws, touch latch pin, 2 -5 mm shelf pins

table saw ,planer, miter saw, sander, drill press, basic hand tools, dado blade, 5 mm and 10 mm brad point drill bits

patience... lots of patience...

Step 1: Top Construction Part 1

The first thing to make is the center section, which is made up by alternating 8 strips of walnut ( 2 mm wide x 14 mm thick ) and 9 strips of maple ( 8 mm wide x 14 mm thick ) all around 76 mm long ( 3'').

Tape the pieces together on one side then open up on the other side and apply glue, lay flat, clamp and remove excess glue, let dry.

Step 2: Top Construction Part 2

Cut a piece of walnut approximately 500 mm (20'') x 200 mm ( 8'' ) wide and plane down to 14 mm thick, rip into 3 pieces with the middle piece being 76 mm (3'') wide. I used one board instead of three separate pieces to maintain the grain pattern on the top.

Take the center piece and cut it in half length wise. Glue and clamp one piece to both ends of the alternating maple and walnut center section. Clamp it in between two scrap pieces to keep it straight or down to a flat surface and let dry.

After the piece is dry carefully rip into 12 mm ( 1/2'' ) wide strips using a fine tooth sharp blade in your table saw.

Step 3: Top Construction Part 3

Cut and mill 2 pieces of walnut and 5 pieces of maple 5 mm thick x 14 mm high and 500 mm ( 20'' long ). Cut the strips as in the first photo, alternating the maple and the walnut.

Line up the pieces including the two outside pieces and tape one side, flip over and apply glue in between each piece, lay flat, clamp and let dry. Note - remove excess glue with a scraper before it fully sets, or wipe with a damp rag.

After the piece is dry, sand both sides flat.

Step 4: Tumblers and Top Dados

Set up a 10 mm wide dado blade in your table saw and then cut four dado's 10 mm high down the four strips in your layup. Sand inside the dado with a small block and fine sandpaper.

Mill some strips 9.5 mm x 9.5 mm ( I used solid beech wood ) and cut to 220 mm long. You need four for the tumblers, one for the locking pin and a couple of extra for the bolt latch pieces. So 7 in total.

Line up the tumbler pieces and tape them together, mark 9 lines, 10 mm apart. Set up your drill press and drill 5 mm diameter holes 6 mm deep on all the lines on your tumblers. Lightly sand the tumbler sticks and make sure they all slide easily in the dados of the top.

Step 5: Tumblers and Locking Pin

Center the four tumblers in the top piece with the holes facing down and tape in place. Using the same 10 mm dado set up as before, run a cross cut dado exactly in the center only 3 mm deep ( 1/8'' ) ( this is for the locking pin to slide in ). In the same cross cut dado ( only on one side of the tumblers ) raise the dado back up to 10 mm high and cut up to the tumblers but no further.

Draw on your locking pin where the tumblers are located, then cut a 3 mm x 10 mm wide dado across the locking pin. On one end of the pin glue a 7 mm x 10 mm ( tapered up on one end to match the dado saw cut ) and drill a 5 mm diameter hole 10 mm deep ( for two magnets to be glued in ).

Make three pieces with a 10 mm x 7 mm deep dado in the center 100 mm long ( 4'' ) these are to hold the locking pin in position.

Step 6: Box Construction

The sides are made up of three pieces glued together. The bottom maple piece is 88 mm high x 16 mm thick ( 3 1/2'' x 5/8'' ), the walnut strip in the middle is 16 mm high x 16 mm thick ( 5/8'' x 5/8'' ) and the top maple piece is 38 mm high x 16 mm thick (1 1/2'' x 5/8'' ).

The two sides are roughed out at 500 mm (20'' ) long and the two ends need to be roughed out at 230 mm ( 9'' ) long with an exact 76 mm ( 3'' ) opening left in the walnut space. The two ends were done in one long piece as opposed to two separate pieces so that it would still be able to run thru the planer .

After the glue is dried run the pieces through the planer and bring down to 15 mm ( 9/16'' ) thick. Sand both sides and then miter the ends of all four pieces using a miter saw or a cross cut sled on a table saw .The finished length of the sides is 445 mm ( 17 1/2'' ) long and the ends are 202 mm ( 8'' ) long.

Cut a 6 mm x 6 mm ( 1/4'' x 1/4'' ) rabbet down the inside on all four sides for the bottom panel to sit in. Glue and tape the four sides together and then machine a 6 mm (1/4'' ) thick bottom to fit.

**Do not glue the bottom in until you are sure the lock works correctly !!!!

Step 7: Dowel Pin Holes

To drill the dowel holes I made up a 38 mm ( 1 1/2'' ) template block with three 10 mm holes 22 mm ( 7/8'' ) from the edge and 41 mm ( 1 5/8'' ) apart, done on the drill press to ensure the holes were straight up and down .

Cut two pieces of 15 mm thick solid stock the inside width of the box times the inside height of the box minus the thickness of the top, clamp the template block and the inner piece to the box. Drill the three holes 30 mm ( 1 3/16'' ) into the inner piece. Do both ends and then on the back drill the same hole pattern just deep enough ( 6 mm ( 1/4'' ) deep ) to glue fake walnut plugs into ( so the back to matches the front ).

Step 8: Handle and Interior Slider

Remove the inner pieces and cut a 25 mm ( 1'' ) strip off the ends with the holes, glue the two strips into the front corner of the box using the drill bit to align the holes. In the off cut pieces drill three 5 mm diameter holes 6 mm deep where the dowel pins will line up. A magnet will be glued into these holes to hold the dowels in when the handle is drawn back.

Cut the two slider pieces to 101 mm ( 4 '') long. The handles are two blocks glued together, the outer block is 150 mm ( 6'' ) x 22 mm ( 7/8'' ) x 16 mm ( 5/8'' ) thick, the inner block is 16 mm ( 5/8'' ) thick x box side thickness plus a hair ( to allow clearance for the handle to move ) and 51 mm ( 2 1/4'' ) long, offset the inner block by 19 mm ( 3/4'' ) on the outer block when you glue together.

Move the handle and sliding block all the way forward, clamp and screw together ( always pre drill your screw holes ). The handle should now move the inner block back and forward. Move the handle all the way back and cut the remaining piece of the block to fit. Drill and glue two magnets into the back of the slider piece and the rear block ( match up magnets ). This is to hold the handle in the closed position.

Step 9: Magnetic Pin Construction

The pins are a 10 mm ( 3/8'' ) dowel with a 5 mm hole drilled 11 mm deep in the end using a drill press. Glue two 5 mm x 5 mm magnets and one 8 mm x 3 mm magnet into each of the dowels using epoxy ( photo #2 ). Make sure you have the same polarity on all six pins !!

Sand the dowels so they slide easy in the holes and cut slightly longer, Then sand down flush to box with the pins in the retracted position.

Step 10: Other Bits

To position the back pins on the lid, drill two 5 mm holes through the back into the lid. Glue 5 mm shelf pins into the back of lid and plug the holes in the back of the box half way with the walnut plugs.

I used a spring loaded pin ( used for touch latch doors ) and glued it to the inside of the box.

Router out a notch on the front inside of the box for the locking pin to slide into.

Before final assembly lightly wax the dado's in the top and the tumblers to ensure easy movement.

Step 11: Setting the Combination

So on the top of the box there are four rows of nine squares, which basically represents four rows of numbers 1 to 9. I decided not to put any numbers on the top, so as not to give any indication that a combination was required to open the box.

Looking at the side of the tumblers pick your combination ( example 1,9,3,6 ) insert a magnet into the correct tumbler hole ( no glue !! ) and use another magnet to hold it temporarily in place. Place tumblers in dado's ( bolt removed for clarity ) Replace cover plate and put bolt back in, remove the holding magnets. The combination can be changed by removing one of the cover plates and moving the magnets in the tumblers.

Test and test again before you glue the bottom in !!!!!

After everything works, disassemble and finish all of the pieces. I gave it two coats using a wipe on beeswax and orange oil finish.

Step 12: Conclusion

I had a lot of fun figuring out the mechanics for this project and the build at times was very challenging. I looked on line for something like this but was unable to find anything remotely similar. I hope my explanation did not get too long and was clear enough to follow.

One thing I can not stress enough is check and recheck the polarity on all of the magnets before you glue them in place !!! Things don't work so well when the magnets repel each other when they're suppose to attract.

Cheers : )

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    55 Comments

    0
    OspreyGozo
    OspreyGozo

    1 year ago

    I love the way you used magnets to disengage the locking mechanism. I think I will integrate a similar method but use 3D printed parts since I am not equipped well enough for a wood working project of that level of precision. Well done!

    0
    neslo63
    neslo63

    Reply 1 year ago

    I think you could easily incorporate the locking mechanism using a 3D printer and when you do please make sure you send pics or do an instructable .
    Thanks
    Cheers

    0
    DICK121940
    DICK121940

    Question 1 year ago

    I am fascinated by this and am going to start work on one soon. I completed Derek Hugger's Colibri recently and have been looking for a new project this winter. I fully understand why one could not make a living doing this kind of work. Nevertheless, it appears you have reached perfection and have a good amount of patience. Richard Campbell, "Keep Calm and Make Sawdust".

    0
    neslo63
    neslo63

    Answer 1 year ago

    First off, thank you for saying I've reached perfection ( not there yet ) and I am honored that you are choosing to do my project especial after completing Derek Hugger's Colibri which in my opinion is quite amazing. The engineering involved to figure out a humming birds movements blows my mind. I had so much fun coming up with the magnetic combination that I have started work on a similar type of box ( two in fact one for each of my grown daughters ) with a few more puzzles involved, more magnets and possibly a rotary combination. At present I am in the design stage and almost ready to head into the shop once I iron out a few tricky details. I look forward to seeing how your project turns out.
    CHEERS :-)

    0
    DICK121940
    DICK121940

    Reply 1 year ago

    I have started your Keep Sake Box and my first question is how long can I make the 10mm x 10mm walnut plugs. I plan to glue them in before I cut the top to length. I also have the box about half done. What a fun project this has been - so far. Thank you. Richard Campbell, 113 Paris Hill Road, South Paris, ME 04281

    IMG_0424.jpg
    0
    neslo63
    neslo63

    Reply 1 year ago

    Ok from what I can see in the pic you have to make sure the last hole in the tumbler must line up with the last square . It looks like you need to move the tumbler another 1/4 '' outward so then you will have to move the 10 mm x 10 mm walnut plugs 1/4 '' farther out and I think my 10 mm x 10 mm plugs ended up about 3/4 '' long. hope that helps. Oh and by the way well done !! I thought I was looking at one of my pictures. I can measure mine later tonight when I get home, but it wont be till late ,Please keep me updated on your progress and I will try to answer your questions asap.
    Cheers
    Peter

    0
    DICK121940
    DICK121940

    Reply 1 year ago

    You were correct, of course. Thanks for your input. I have attached a new pic of my progress and have a few more questions. 1. How much clearance did you allow for the top to fit in the box to allow for humidity, etc.? 2. I have not glued in any magnets yet and am wondering how you applied a two-part epoxy in the holes and/or on the magnets themselves. 3. What is the actual length of the locking pin? Thanks in advance, again. (By the way, I have had "fun" chasing magnets all over the place).

    IMG_0429.jpg
    0
    neslo63
    neslo63

    Reply 1 year ago

    I will start by saying Looks great so far !
    1. I left about 2 mm in total a little more than 1/16 which made it easy to get the lid in and out but depending on the original moisture content of your wood and how much your humidity changes through out the year you might have to leave a little more.
    2. I first mixed up a little J B weld 5 minite epoxy and glued the two 5mm magnets to the 8mm magnet, just put a bit of epoxy on the face and try to carefully let the magnets come together . Once that has set I cleaned off any squeeze out then using a tooth pick apply very little epoxy in the hole on the side then a little on the magnets.because the glue might wants to pop the magnets out due to air compression clamp them together with tape until set.
    3. The locking pin is just a bit less than the width of the box lid to allow for clearance when you put and remove the lid.
    Sorry I ordered my magnets off of amazon, I should of provided a link.
    Carry on but remember to not glue the bottom in until your happy with the locking mechanism or just screw the bottom on and cover the screws with felt pads just in case.
    Wait till you see the puzzle box I plan on submitting in the heart contest.and keep on sending progress pics
    Cheers

    0
    DICK121940
    DICK121940

    Reply 1 year ago

    I made more progress today but do have some questions. 1. My locking pin is 9.5mm square but the piece to add on is listed at 7mm x 10mm. So - how do they fit together? Also, the picture of the locking pin shows two thin pieces added to the top. Is there a size for these two pieces? And, what do they do? I am not sure just how the locking pin works, either. 2. I am waiting for a 1/2" cove bit but now that I have the box together how do you recommend I rout out for the locking pin? I assume the straight edge of the rout has to be even with the bottom of the lid. 3. When I watch your video I don't understand why you slide the magnetic pins the way you do since you know the combination.

    IMG_0433 (002).jpg
    0
    neslo63
    neslo63

    Reply 1 year ago

    Well your almost there :-) Just trim your add on piece to 9.5 mm wide the same width as the locking pin and glue on. The purpose of this is just to bring the magnet closer to the lid.
    The two small pieces added on top are just stops glued on after to prevent the pin from sliding out ( 3 mm x 9.5 mm x 16 mm long ).
    The locking pin travels from the back of the box to the front and slides into the routered out hole in the front, it can only move when all four tumblers have there dadoed out section in line with the locking pin (right in the middle ) once the locking pin is engaged (into the front of the box ) the tumblers are free to move back and forth (side to side in their dados ) but in doing so prevent the locking pin from moving from the front to the back and into the open position.
    2. I just cut two scrap pieces that fit into the box from front to back and came up flush to the top of the box and spaced them out about 38 mm ( 1 1/2'' ) apart in the right in the middle of the box where the locking pin is located, then placed a couple clamps on the outside of the box to pinch and hold the two scraps in place ,and then clamp the whole box down so that it does move when your routering.
    I then used these pieces to set my router base on, drop my bit to the correct height and rout the hole in the front of the box (very carefully ) for the locking pin. If you are worried about the bit wanting to travel you could always make a stop for the bearing on the bit in between the two scrap pieces
    Yes the straight edge on the router bit is on top but it is not even with the bottom of the lid but up 3 mm so that it is in line with the top of the locking pin that is routered 3 mm into the lid.Before you router in the hole for the locking pin place the lid in position without the locking pin and mark the exact location where you need to router out.
    3. In the video I slide the pins slightly past the combination number and then bring them back just to ensure the tumbler does not get hung up and moves to the correct number, I probably don't need to.
    Hope this help clarify a few things.
    Cheers

    0
    DICK121940
    DICK121940

    Reply 1 year ago

    Can you tell me what is perhaps wrong by looking at the attached picture? I have all the parts made and have applied walnut oil to both sides of the top. I need advice on positioning the spring loaded latch which seems obvious but...…….how do I push the lid down a bit to release the latch?
    Am I correct in my thinking the lid is locked to start with and the tumblers are able to be moved left or right. If that is the case I have something wrong because the notches in the locking pin do not line up with the notches in the tumblers. If I do line up the notches I am able to slide the tumblers left or right with the four pins. It seems as if I am missing something that is right before my eyes. (and brain)

    IMG_0442.jpg
    0
    neslo63
    neslo63

    Reply 1 year ago

    From your photo its hard to tell exactly whats going on , but I took a few close up of mine. The first and second photo shows the locking pin in the locked position , the tumblers are free to move back and forth. The last photo is when the combination has been met and the locking pin is unlocked the tumblers are no longer able to move. Hope this helps. As for the spring loaded catch it just a matter of moving it up and down until it seems to work, the other option is just to leave it in a position that always wants to push up and use the locking pin to hold the lid down, which means you would have to push down on the lid a little to move the locking pin with the magnet after meeting the combination.
    Check out my latest instructable I submitted today All My Hearts, combination puzzle box .

    IMG_4276.JPGIMG_4277.JPGIMG_4278.JPG
    0
    DICK121940
    DICK121940

    Reply 1 year ago

    Except for attaching the bottom I finished the Keepsake Box today. And it works! I will work on a video for proof. I will attach the bottom after a while to see if anything is amiss. I used Mahoney's Utility Finish for a first coat and Mahoney's Oil Wax Finish as a top coat.

    IMG_0451.jpg
    0
    neslo63
    neslo63

    Reply 1 year ago

    Wow Awesome Job !! Well Done I hope you had fun and I look forward to the video.Please make sure you post a picture to the bottom of my instructable where it says I Made It. And once again I feel humbled that you chose to make my project.
    Cheers :-)

    0
    NortonCreations
    NortonCreations

    1 year ago

    This is fantastic! Such great creative skills!

    0
    neslo63
    neslo63

    Reply 1 year ago

    Thanks for the encouragement.
    Cheers :-)

    0
    neslo63
    neslo63

    Reply 1 year ago

    Thank for the great comment and I see that your also into woodworking so ( Keep calm and keep on Cabinet making )
    Cheers

    0
    tomp0209
    tomp0209

    Reply 1 year ago

    Amen, brother!
    You set a good example to us.