Introduction: Simple Vault Mechanism

Picture of Simple Vault Mechanism

Sometimes, a simple latch just won't do. In a recent project, I had to design a circular lid that would lock from the inside. However, as I didn't want any hardware showing on the outside of the lid, I needed to keep all the moving parts inside. Using this vault-like mechanism has the advantage of being easy to build if you have access to a laser cutter.

Step 1: Materials & Tools

Picture of Materials & Tools

You will only need a few common items to build this lock.

  • 1/4" Birch Plywood
  • 4 small screws
  • 1/4" dowel
  • Wood glue
  • You preferred wood finish (I used wipe-on polyurethane)

Even though, this mechanism can be built with traditional tools, it will be way easier if you have access to a laser cutter and a drill.

Step 2: The Lid

Picture of The Lid

The diameter of the lid is up to you. It doesn't even have to be a circle as long as the arms of the lock still protrude when they are in the "locked" position.

A smaller circle is cut in the centre of the lid. This part, when rotated will give motion to the arms of the lock. In my design, this circle is hollow because I needed to accommodate room for a threaded rod.

Step 3: The Arms

Picture of The Arms

The arms of the lock will slide on a 1/4" dowel. The length of the hollow part of the arms dictates how far these will travel outwards of the lid. Make it longer if you need a longer travel.

Step 4: The Axis

Picture of The Axis

4 hole pockets are drilled on the inside of the lid. Dowels are glued in place. 4 caps are laser cut and drilled halfway through. These will keep the arms in place.

Step 5: Arms Assembly

Picture of Arms Assembly

The arms are screwed on the rotating centre. You can now fit the whole assembly on the inside of the lid, making sure that the axis go inside the arms pockets.

Step 6: The Lid Handle

Picture of The Lid Handle

To rotate the centre of your lid, you will need a handle. I decided to cut a circle slightly larger than the rotating part and glue those 2 together. The fact that the handle is larger prevents the central ring from being pushed through the lid.

Step 7: Finishing

Picture of Finishing

In my project, I use the lid to close the opening of my telescope. As the lid does not have any support, I added some small tabs on the side to make it flush with the end of the tube. It also prevents the whole lid from spinning when rotating the centre part.

If you want to protect the wood from stains and humidity, you can apply a few coats of polyurethane varnish or some linseed oil. As birch doesn't stain very well, I decided to go with a clear finish.

Step 8: The Result

Picture of The Result

This mechanism is very basic and can be improved on many aspects. However, it is a good starting point for more complex movements. It is also a good project if you are new to laser cutting as almost all the parts can be cut from a small piece of plywood.

If you want to build your own, I am providing an SVG file of the whole mechanism. Have fun with it and please let me know if you've successfully built your own!



cnaughtin (author)2016-07-28

Wonderful 'ible!!! One comment - the side walls of the peg slots look awfully thin. The quantity of operating cycles this item would experience in its lifetime might be so small that it wouldn't matter, but simply doubling the thickness would make a huge difference for potential wear problems and would make it appear a bit more solid. Operation cycles could be surprisingly high if it had a long lifetime.

ThomasJ1 (author)cnaughtin2016-07-28

You're absolutely right. In my case, there's not much stress applied to it as it serves as a cap for my telescope. But it you use it for a door, you might want to enlarge these walls. Also, the peg caps can be made larger to cover the entire slot. That way the arms won't be bending on that weaker spot much when someone's pulling on the door.

andrewty (author)2016-07-27

Please do a couple of instructables for telescope making.

Can't get the reply to work so adding comment here instead.

ThomasJ1 (author)andrewty2016-07-28

I have a few astronomy related Instructables coming up. In case you missed it, here's the one about the telescope

jrudolchick (author)2016-07-26

This is very cool and well explained.

ThomasJ1 (author)jrudolchick2016-07-27

Thank you

ivandrake (author)2016-07-26

This is exactly what I was thinking of using for a box project I'm planning. However, I'd like to cover the mechanisms to protect them from damage by the contents. Any suggestions? I was thinking a kind of "shell", like a hollowed out board covering the whole thing or a framework just to support a veneer, unless there's a better option.

ThomasJ1 (author)ivandrake2016-07-27

A plexiglass panel can be a good option if you want to protect the moving parts while keeping it visible.

CarlW21 (author)ivandrake2016-07-26

A flat round piece glued to the dowel caps in step five?

ivandrake (author)CarlW212016-07-26

Ah, yeah, that's pretty much what I was thinking. And I forgot to mention that my plan is for a square lid on a cubic box.

diy_bloke (author)2016-07-26

looks great. May use this in something I am making

ThomasJ1 (author)diy_bloke2016-07-27

Great, post a picture once it's finished :)

JGDean (author)2016-07-26

I like your application as well as your execution, but it's not a new concept. Most garage doors use a similar method of locking, rotating two bars into holes in opposite sides of the door. Similar two-, three- and four-point latches have been used on security doors and odd-shaped doors (like the round ones seen in The Hobbit) for many years.One of the nice things about them is that they don't have to be in any particular position on the door - just change the lengths of the bolts..

ThomasJ1 (author)JGDean2016-07-27

You're right, this mechanism has been in use for a while. I thought I would make an Instructable to share the concept with other makers. Thanks for mentioning the fact that the rotating part doesn't need to be in the center.

StephanP1 (author)2016-07-26

Cool project. This is exactly what I was looking for. I will build one, but without a Lasercutter. If it is done, I post a picture here. Thank you for sharing your idea!

ThomasJ1 (author)StephanP12016-07-27

Glad you like it. Of course you can make one without the laser cutter. It just makes things quicker if you have access to one.

meswanson (author)2016-07-26

Nicely done. Who cares if you did not invent a new concept. Most concepts here are just variations of an existing idea. Nice to show a way to do it. Keep it up please!

Technoshaman (author)2016-04-23

This is exactly what I've been planning on using on the lid of a dry/wet tumbler I've been working on. Thank you :)

VyreRain (author)Technoshaman2016-04-30

I was thinking the same thing , although I would use steel =P

Technoshaman (author)VyreRain2016-05-01

I will use steel for the rods and the mechanism, and the lid will be polyacetal :)

Ca. RAFAEL FELIXXO (author)2015-08-03

excelente gracias por compartirlo

SteveC30 (author)2015-07-30

This is a fairly good approximation of a shipborne hatch we've used in the Navy for years pic included.

ThomasJ1 (author)SteveC302015-07-30

Thank you Steve for the picture! I didn't even think about looking up if this mechanism was already being used anywhere. I figured it would though. It's funny to see how similar the design is. I just feel like I re-invented the wheel now :)

IzidorL (author)2015-07-30

Step 1: get an industrial laser cutter

BladedFury (author)2015-07-27

I love this idea, dude. I'm gonna use it to make a crazy epic door to my room/workshop, except I'm only going to use one bar instead of the four you show.

HFHI (author)BladedFury2015-07-27

I bet it'll work really great if you set it up with one of those Kwikset smart key locks with push buttons as well as the keyhole. This way you don't need to have your door key around everywhere you go. However I recommend having a spare key buried somewhere nearby outside your home in case the batteries die out on your lock.

BladedFury (author)HFHI2015-07-28

Actually, I think what I'm going to do is cover the door with designs and stuff, and hidden in one or two of the designs is the button to press, knob to turn, etc to unlock the door. Nothing too fancy, but still enough to keep the layman out of my workshop :)

terrefirma (author)2015-07-27

Very elegant.

jking17 (author)2015-07-26

If you use two dowels and a longer top, it would strengthen the lock arms by not requiring slots in them.

ThomasJ1 (author)jking172015-07-27

Thanks jking, you're right about the strength but the reason for the slots was actually to limit the movement of the arms so that they don't extend too far outside and also don't hit each other when you retract them.

MINDLESSFIREBALL321 (author)2015-07-26

I built this today out of cardboard and paperclips

jeanniel1 (author)2015-07-26

Very clear and well-written, with great pictures accompanying the instructions! Thanks for putting this in!

golddigger1559 (author)2015-07-24

Please tell me there will be an ible for that telescope. That is gorgeous

ThomasJ1 (author)golddigger15592015-07-26

I've had quite a few requests, so I think I'll make one indeed.

Marc - FR (author)2015-07-26

that's clever and well realized! Thank you for that instructable =)

Is it a home made Newton you have?

ThomasJ1 (author)Marc - FR2015-07-26

Thanks Marc. Yes, I'm thinking about making an Instructable about it.

Georgeh3 (author)2015-07-26

GREAT LOCK IDEA. I am considering making this type of mechanism for an Arduino powered safe out of steel.

richg99 (author)2015-07-26

Thanks for posting this. Gives me a number of good ideas for a watertight lid for my kayak.

batonas (author)2015-07-24

this needs a video or a gif so bad...

ThomasJ1 (author)batonas2015-07-24

What about the gif at the top of the page?

batonas (author)ThomasJ12015-07-26

must of missed it, looking smooth.

kylegilbert (author)2015-07-25

Love this. Looks really nice.

sboja (author)2015-07-25

A video would be nice =)

studleylee (author)2015-07-23


mp 15-22 (author)2015-07-23

hey I really like this mechanism it's something I've been looking for on here to see exactly how one works but simple to make. do you think it could be made from steel and used to lock a room door (bedroom)? I'm a metal fabricator and welder so working with steel is simple.

ThomasJ1 (author)mp 15-222015-07-23

I haven't tried it myself, but I would say that it's feasible. You probably don't need an oversized central ring, but you'll need longer arms to reach the door frame. A fancy addition in your case would be to use ball bearings wherever there is friction. That would make your build really smooth. Also, you shouldn't have to worry about gravity for a vertical set up since the downward pull from the upper arm is compensated by the weight of the lower arm. Good luck and let me know if you make one!

seamster (author)2015-07-23

This is awesome!

Are you planning to share anything on that homemade telescope? That looks phenomenal.

ThomasJ1 (author)seamster2015-07-23

Thanks Seamster,

I really want to write an instructable about the telescope but there is so much steps involved, I'll have to figure out how to present them all. Maybe 2 instructables, one for the mirror and one for the tube & mount.

JON-A-TRON (author)2015-07-23

This is awesome! Thanks for sharing.

About This Instructable




Bio: Most of the things I build usually relate to either astronomy, physics or woodworking in general.
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