How to Look for a Proper Lock to Secure Your Home - a Guide to Improve Your Security

Introduction: How to Look for a Proper Lock to Secure Your Home - a Guide to Improve Your Security

About: I like to improve myself and things I find :) Learning new things every day is next to impossible but I still try - only a working brain can work. I have no special sector to cover, electronics, electrical stu…

This was planned to be an Instructable without pictures, but I had to realise without pics it is hard to understand, so I added some as well as video clips.

I have massive problems finding links for pictures of keyways that have no copyrights on them and my local stores only provide a very limited varition and they did not like me taking pictures for some reason, at least not without buying every lock I want a pic of.

For a better understanding of keyways later in the Instructable I recommend to do a Google search for for keyways and to check the images you find for reference.

Sorry for the troubles I cause.

It will also be quite long, but I keep it on one page in a simple form.

Just read through it and make your own thoughts about security - take the info provided to upgrade or update the security level around your home or workplace.

What is this about you might wonder?

It started with my hobby, lock picking, and the sad fact that most locks I found on doors, deadbolts and security screens, as well as padlocks, were quite easy to pick or bypass - which is even worse...

I already posted an Instructable showing the design flaws in the popular Master 175 / 178 combination padlocks (don't buy them and if you did put them in the bin).

But I was asked: What actually makes a good lock and is there a way to check before buying?

The answer is not always easy ;)

So let's start at the beginning...

The normal locks as we use them all day have certain design features in common.

First of all the tumblers that match to your key, secondly that they use a rotary motion to unlock.

There are other types of locks that are better, but more about that further down...

In our standard locks the tumblers are made from tow pieces and a spring.

If the correct key is inserted the area between the halfs of a pin aligns with the shear line of the lock - you can turn it.

Only one tumbler in the wrong postion and you won't be able to turn the key.

Sounds fairly secure doesn't it?

The problem is in tolerances and key ways.

A cheap 2$ lock won't have tight tolerances and usually comes with a pretty straight key way.

A good lock with a high security rating with have very small tolerances and a "weird" locking key way, often with several bends in it and very narrow compared to a cheap padlock.

Aditionally a good lock will also have one or more so called "security" pins or tumblers.

They can be anything from being serrated to having a mushroom type head or even a smaller diameter on the tip.

Their sole purpose is to make life hard for us lockpickers.

I will explain more about this further down as well ;)

If you checked Google for key yways and profiles you will find a chart from Masterlock as well, I will now refer to this chart of key ways.

In the chart you can see a few different keyways, they are the design of MASTERLOCK, other will have slightly different shapes but for our purpose it is just fine.

I will try to point out which type I think is secure or unsecure and why, I will address the key ways by their label in the top.

D200WP is very narrow, which is good to avoid general picking attempts but it also has a pretty straight key way in the area where we find the tumblers. All it takes is a tool that is slim in shape...

D10 on first look seems to make it more complicated but if you look closely you will see tumbler line passes through the odd shape, same for D01, D29, D07, D13, D12, D11, D36, D70, D04, D34, D28, D13 and D15.

D08, D30 and D03 are the only ones I would consider more complicated to pick than usual as it requires good and precise tools that not everyone has in his pocket.

Again, this is only for the key way itself but that's where it all starts...

Use the charts as a guide and you will see a key way that is narrow and has some good curves in it will be a good choice.

The only way to fool them fast is by using a bump key but that requires that the crook has a blank key with the same profile...

All the other shapes can be very secure too given they have proper safety pins included and tight tolerances but they make manipulations much easier - and we want to avoid easy in this case!

Ok, I see, now you want to know how this thing with the tumbler works, so please check this

Wikipedia link

Ok, basics covered, but if pin tumbler locks are so insecure anyway - are there other options?

Yes, there are!

For example Abloy has so called disc detainer locks - instead of pins freely rotating disks are used.

Check the Abloy website or this promotional video:

I, personally consider the current Abloy range the top of the range in terms of security based on the locking system.

Add a proper case for this cylinder and a secure door and you can sleep well ;)

There are also pin tumbler locks that are considered to be extremely safe, for example the Bi-Lock style:

Wikipedia - Bi-Lock system

Please be aware that "safe" with these types of locks is only true if they are the latest generation.

Cheap imitations only use for pins on each side and can be picked by a child.

The good ones not only have at least 6 pins on each side but also locking systems on the side - a magnet, some little holes and so on.

If you do go for this type of lock seek advise from a good locksmith in your area so he can explain and show what types he has available.

In case he only has the standars 6+6 pin systems with flat sides on the key, avoid the lock as it can be picked.

Some other types of locks are available too but hard to find and get for the normal home owner.

If you know about high security lock systems for private use that should mentioned please send me some info by PM and I will add the information here!

What about those nice electronic locks that every fancy house "must" have?

As there are too many possible types I will try to break it down.

a) Key system...

The electronic key should be on a frequency outside normal communication ranges, so avoid cheap asian knock off's!

The main thing is that the key should be not read out remotely, for example by someone standing on the nature strip.

If your key unlocks the door while you are still 5m away it is crap.

The key should also "rotate", meaning that after each use the system generates a new key.

Fingerprint sensors should be avoided as so far I was able to fool them all with very little work after obtaining a correct fingerprint - and you won't believe on how many places I could get your prints...

b) Installation of the electronics....

Trust me if I say there are locks out there that have the vital electronics sitting behind a metal cover on the outside of the door - only use those where the electronics are on the insde of your door!

c) Bypass system in case of power failure....

This is the only weak point for most electronic systems.

What is the point of millions of possible key combo's, short range and foolprof design for the electronics if there is a simple keyhole to override the electronics and open the door??

A good lock should have a low power warning light and still able to operate for a few weeks in that state - if the lock has no such feature avoid it!

If there is a key to override make sure the original cylinder is replaced by an Abloy Protec cylinder of the latest generation.

Also demand proof that the case is tamper proof, meaning hard to drill in and even harder to destroy by brute force.

Ok, I got all of that, is there anything else I should consider to make my locks more secure?

Yes, there is ;)

US homes, as most homes in Australia use a simple wooden frame, put some windows and doors in it and cover the inside with plaster boar and the the outside with some bricks.

Basically a better looking shed...

The doors often come cheap as well in a tow layer desing.

A thin sheet of wood on both sides with some cardboard between them.

To make things worse, the plate to match the lock on your door is just screwed on with short wood screws.

Also the beam is weakend by the cut out for the same.

If you have one or more deadbolts chances are the beam next to the door is already weak enough to be kicked in...

Having nice windows right next to it, with only the wooden beam seperating them from the door is also a bad weakness.

But there is a way to improove this:

Attach a strip of flat steel from floor to ceiling (or all the way if you are renovating) to increase the structural integrety of the frame.

The same should be done on the side with the hinges...

If in doubt use another strip on the outside and drill holes through all to secure it - but use bolts that can't be undone from the outside or weld them in place on the outside....

Is there any option to improove on a low budget?

It comes down to the level of security that you want and that is possible.

In a rented property your options could be very limited but even there is a way!

There are system on the market called "deadbolt secure", "deadbolt latch" and so on.

What they do is to hold the handle of your deadbolt in place.

So basically a U-shaped piece of steel that slides or folds over the handle, making it impossible to turn even if someone picks the lock on the outside or tries to force it with a screwdriver.

A simple DIY solution could be as easy as drilling a small hole into one end of the handle and to use a strong cord to secure it to a good screw or the door handle.

Dyneema line as used for many kites is good for the job as a 3mm line already has over 200kg of breaking strenght.

And now some pictures from locks I could find around here:

In the above pictures you see a quite secure keyway. Why is it secure?
Well firstly it uses 6 tumblers instead of the usual 5, that means it is longer making it harder to reach and pick the last tumblers.
Secondly the keyway itself is extreme narrow and with "steps" and corners - this makes it almost impossible to insert and use a pick and would require special equippment.

Notice the spacing between the pins, making the cylinder very long compared to a standard 5 pin.

This is an example of a very bad keyway, it was gutted, so don't mind the missing tumblers.
The keyway is totally straight and quite wide, even a toothpick would fit in there to do the job...
Although this lock also used 6 tumblers, no security pins were added making it very easy to pick.

This is a standard deadbolt as it is widely used around the world, 5 tumblers, straight keyway and more than enough room to use tools to pick it.
You will see this in a video further down...

This is from a cheap Chinese padlock, on the packing it stated "high security level, very hard to pick".
Needless to say it only has 3 tumblers, no safety pins and was picked with a straight tool.

Same brand but a slightly different keyway.
They even stated that the keyprofile adds to the overall security of the lock....
Only difference is the bend in the keyway but it is far too wide, so any normal pick can be used to open it in no time.

This is from a door lock and you can see the attempt to create a nice keyway that is hard to pick but they failed as again the thing is far too wide. The same shape but only .5mm thick would be great.

Another example for a very bad keyway.
Not only are the tumblers really close but only 4 are used.
Useless in terms of security as the keyway is also wide and straight.

A standard "Wafer-Lock" as used in many security flyscreen doors.
People often think the double sided key gives more security and is harder to pick.
The fact is that, as the name suggests, these locks use wafers instead of pins and tumblers.
Being cheap in production means wide tolerances and with no added extras very easy to pick - even with a hairpin...

And now some videos showing some of the above locks and why they are so insecure. Don't worry, you will only see how I open them but not actually learn any picking skills from it.

Standard Deatbolt

Security screen wafer lock

High security padlock defeated with a pick gun in no time - that is why a "complicated" keyway is so important.

Some food for thoughts, a collection of Youtube videos showing very secure lock systems:

The weirdest lock on earth almost impossible to pick):

The "Forever Lock" - totally unpickable at this stage:

Dual cylinder padlock (considered unpickable for now):

These were just a few examples of some genius designing good locks, just to give some idea about what is possible if you need a higher level of security.

But any lock is only as good as the door it is mounted in, so check the difference for high security doors:

As you can see a strong door with last longer than standard bricks holding it in place...

If you want to know if a lock you have a want to buy is secure you can check Youtube with the name of the lock plus the added search term "picked" or "bypassed".

I am not linking any videos showing how to pick a lock as I don't see the benefit for an Instructable helping with security.


I noticed there are some more Instructables out there with more or less helpful suggestions to improve the security around your home.

If there is some interest I might make anotherInstructable covering more of the physical aspects of security

E.g. how to raise the security level of standard doors and windows, basic about ecurity systems and what to watch out for before buying, physical barriers for remote properties that are unattended...

But I would have to rely on your feedback here as conditions "Downunder" in Australia are a bit diffrent compared to the US, Canada or Europe.

I just think that the things we value should stay safe at all times and that a sound understanding of the topic migt help some people to feel a little bit better about their security...

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    8 years ago on Introduction

    I think it is not to make people feel bad about their security ;)
    I think, if you know what is a bad choice for a lock it will help to get the good stuff once you decide on an upgrade or build a new home.

    There are some people out there that take advantage when there is a gain, making illegal activities hard enough to no bother is the key.

    Much more could be said about the actual picking of locks or how to overcome basic security features with ease, but it would be overkill and might give bad guys new things to learn.

    If anyone has a particular question burning him or her fell free to contact me and I see if I can assist.


    8 years ago on Introduction

    This is an impressive guide! Thank you for putting all of this info together.

    The only problem I see, is that now I know how insecure my locks are. I was blissfully ignorant before reading all of this. Thanks a lot! :)