Box with a Secret Locking Mechanism

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Project by JamesVavra posted 05-25-2011 02:36 AM 20193 views 41 times favorited 38 comments Add to Favorites Watch

One of the guys at the office asked me to make a box for his nephew. he only requirement: some sort of secret or trick locking mechanism. He and I brainstormed a bit and then I went home to make some prototypes. After he picked one, this is what I came up with.

The dimensions are roughly 9” x 7” and it’s 5.5” tall. The sides are solid maple and the top and bottom panel are maple ply. The miter keys and top inlay are bubinga. Finish is 5 coats of rattle can lacquer rubbed out with steel wool.

The handle is attached to the body with rare earth magnets. They are a bit proud on the handle and a bit recessed on the body, making for a very positive fit – it’s hard to tell it comes off and take a bit of force. Inside the mortise lock, there are two very small magnets that hold the catch in either the locked or unlocked position. The much larger magnet in the handle/key attract the magnet on the bottom side of the catch and allow you to move the catch between the two positions. The locking mechanism works very well. And aside from mis-positioning the hinges by something like 1/64th (and thus causing the lid to be just slightly skewed from the body), I’m pretty happy with it. If I had the time, I’d fill the hinge holes with maple dowels and try again, but I’m out of time on it.

One lesson learned: when working with hidden magnets, do not use steel wool. The little fibers are impossible to remove from a magnet. Sticky tape worked the best, but nothing would get them all off:

Thanks for looking – questions, comments, and criticisms welcomed.


38 comments so far

View bigike's profile


4047 posts in 2381 days

#1 posted 05-25-2011 02:38 AM

very nice box.

-- Ike, Big Daddies Woodshop,

View Rev_John's profile


93 posts in 2981 days

#2 posted 05-25-2011 03:29 AM

The box looks great! I’m still some confused on the “lock”. I love the idea of a hidden lock.

-- John from Jackson, Michigan

View tomakazi's profile


682 posts in 2376 days

#3 posted 05-25-2011 03:33 AM

Great box, I like the secret lock, great idea!!!

-- I didn't go to college, I was too busy learning stuff - Ted Nugent

View littlecope's profile


3018 posts in 2595 days

#4 posted 05-25-2011 03:45 AM

A Fine Job James… It must be pretty frustrating to open, if you don’t know the “trick”!!

-- Mike in Concord, NH---Unpleasant tasks are simply worthy challenges to improve skills.

View sarahss's profile


258 posts in 1742 days

#5 posted 05-25-2011 03:51 AM

that is so very cool—and beautiful. he should really like it.

View JamesVavra's profile


294 posts in 2409 days

#6 posted 05-25-2011 04:11 AM

Here’s a quick and dirty cutaway diagram of the lock mechanism that may make it a bit clearer:


View Arlin Eastman's profile

Arlin Eastman

3229 posts in 1654 days

#7 posted 05-25-2011 04:19 AM

I always like a nice looking box.
Good job on the inlay

-- Please help me help other Vets click..> is always the right time, to do the right thing.

View tomsky's profile


10 posts in 2102 days

#8 posted 05-25-2011 05:08 AM

Interesting lock. I use compressed air to remove small pieces of steel from magnets.
Thanks for sharing.

-- tomsky

View rance's profile


4198 posts in 2253 days

#9 posted 05-25-2011 05:11 AM

Nice job. I really like the dark accent around the top of the lid. Good going on the lock too.

I can’t quite tell but it looks like you used a combination blade for cutting the spline slots. You might try a flat-top rip blade for a flat bottom slot.

-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

View mafe's profile


10541 posts in 2182 days

#10 posted 05-25-2011 08:57 AM

Really nice and who don’t love a secret lock!
The boy will be so happy.
Best thoughts,

-- MAD F, the fanatical rhykenologist and vintage architect. Democraticwoodworking.

View Ken90712's profile


16047 posts in 2281 days

#11 posted 05-25-2011 11:44 AM

Very cool idea I like it!

-- Ken, "Everyday above ground is a good day!"

View christopheralan's profile


1118 posts in 2813 days

#12 posted 05-25-2011 02:02 PM

That is cool! Well done!

-- christopheralan

View ruddy's profile


484 posts in 2032 days

#13 posted 05-25-2011 02:28 PM

Love it..well done

-- And my head I'd be a scratchin'

View EvilNuff's profile


60 posts in 1720 days

#14 posted 05-25-2011 02:33 PM

Nice, I like the lock mechanism.

View moonls's profile


412 posts in 2079 days

#15 posted 05-25-2011 02:56 PM

This box is a nice combo of beauty and design. I’ve only tried using 2 small rare earth magnets as a catch for a small box but your locking mechanism is very clever. Well done!

-- Lorna, Cape Cod

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