Update: Some errors were made in this article, please see the end for the corrections. 

The Medeco M3 is Medeco’s latest commercial cylinder and was released as a replacement for the Medeco Biaxial.  They released both the M3 and the lesser known M3 BiLevel (M3B for short) at the same time.   On the surface both look surprisingly similar, and even with factory cutaways it may not be immediately apparent what the difference is.  We will explore the workings of the M3 and M3B and see what they bring to the table beyond the Biaxial in terms of security and features.  In addition we will take a look to see why the beefy looking M3 BiLevel may not give you much more security than the Kwikset on your front door.

To make things easier to follow I want to setup some standards for this write up.  First of all when I am talking about the M3 Standard cylinder I will refer to it as M3S (S for standard) and when I am talking about the BiLevel I will call it the M3B.   For all the pictures I show I will always have the M3B on the left and the M3S on the right, if only one picture is shown it is safe to assume that feature is the same on both the M3S and M3B. In addition beware that while both are 6 pin cylinders the cutaway only shows the first 5 pins.  I would also like to thank Jon King a lock picker and something of a Medeco specialist (including picking the M3S) for reviewing the technical details of this article.

The Medeco M3S was primarily created to replace the Biaxial when the patent protecting the Biaxial keys ran out.  To extend the patent they added a slider to the lock for added security and once again were able to offer a cylinder with patented keys (meaning authorization is required to duplicate keys).  In addition the M3B was a new type of cylinder from Medeco, a cheaper cylinder (list of $40-70 depending on features), that took the same key as the M3S and was intended to protect things that don’t need protection.   The documentation for the M3B says it best “BiLevel’s patented standard locks offer the appropriate level of security for conference rooms, maintenance closets, break rooms, bathrooms and other areas without risk or valuables.”.   Before we really dive into the pictures and breakdown I am going to say a bit about how the M3S and its predecessors work. 

Aside from simply raising the pins to the sheer line like a standard cylinder, Medeco locks have always had an additional feature of requiring each of the pins to be rotated either left, right, or center (20 degree offset for L/R).  This is accomplished by having a vertical groove cut into each pin and fingers that stick out from the sidebar.  When the proper key is inserted and the pins are rotated all the grooves face the sidebar and the fingers (5 for 5 pin 6 for 6 pin) on the sidebar are able to push into these grooves.  The Biaxial was the first patent extender on this, it added the fact that each pin could be either a fore pin or an aft pin (front or back).  While this didn’t make it harder to pick it did add a lot more possible key combinations allowing for greater master keying.   Finally the M3 came along and added a slider, the slider must be pushed in just the right amount to allow the two fingers on it to enter into the two holes on the sidebar to allow the sidebar to move in.  Confused? Great! It will become more clear as we go through the actual workings.  The M3 BiLevel is really more similar to the Medeco KeyMark than the other Medeco lines.  Both are basically standard cylinders with patented key control, but do not offer much in the way of security.   So lets start looking at these cylinders.

 
We can see the front of the M3B has a B on it for BiLevel but the other difference we can notice when compared to the old Biaxials is a much larger and fairly open (free of wards) keyway.  This doesn’t mean much for a usability perspective but does mean it is easier for a lock picker to insert tools into the cylinder.

 
Looking at the key from the top we can see the angle cuts and also that the valleys are not equally spaced apart (due to the fore/aft positioning of pins).  Look at the side of the key we can see the slider cut to the proper length.

 
As we look at the cutaway side of the cylinder you may be able to make out the mushroom security pin (2nd chamber on M3B and 3rd on M3S).  You should definitely be able to see the silver color of some of the M3S pins, those are the hardened anti-drill pins.  We also get a shot of the sidebar on both of these cylinders.  In addition if you look at the stack heights (top pin height + bottom pin height) they are basically equal on both cylinders.  This ensures equal spring pressure so one could not use the amount of pressure being exerted by a pin to determine its length (it also makes the cylinder much more annoying to pin/rekey due to the fact you must adjust the top and bottom pins).

 
Once the key is inserted we can see the pins all raised to the sheer line.  In addition on the M3S with the 3 bottom pins we are able to see their grooves all pointing out, this is to allow the sidebar fingers (not visible) to push into them.

 
Here we can see where the metal has been cut away to allow you to see the slider moving.  If you look closely you will notice one slider is a bit farther in than the other (just due to different key slider cuts for the M3B and M3S) however the slider mechanisms themselves are the exact same for both.

 
Now we are getting to some real action shots! Here the key is rotated partially to allow a look at the bottom pins.  On the M3B the bottom pins look pretty much like standard pins, in addition you can also see the sidebar (if you look carefully you will not see any fingers).   On the M3S there is much more to see. First of all we can see each of the pins has a hardened anti-drill pin in their center for anti-drill protection.  In addition we can see all the grooves are going in the same direction on the pins (note the nubs at the top of each pin may look like a groove but is not, we will discuss them later).  If you look carefully at the sidebar you can actually see the fingers for 3 of the pins sticking out (will really need to zoom for that one).

 
Further rotation shows us the slider, again on both of them it is the exact same hardware/action.

Now we need to take it apart, the Medeco cylinders are very nice in that these use hex screws at the top of each pin chamber(instead of a bible cap) making for easier repinning than normal.  We can remove these screws and carefully remove the springs and pins, make sure to keep them in order and right side up as it matters (right side up can be figured out later).   Once you remove the pins the cylinders will still not turn even if tension is applied, this is due to the sidebar/slider.  The sidebar cannot move in unless the slider is pushed in the proper amount.  To see how much security is added by the slider apply tension to the cylinder and slowly push forward the slider with a paperclip or small screwdriver, once it reaches the proper amount the sidebar should go in and the plug turn.  It isn’t quite that easy while picking, but its close.

Now while Medeco makes it really easy to repin from the top, taking the cylinder completely apart they made lifetimes harder (at-least on these cutaways).  If you look at the picture above of the back of the cylinder you will notice a C clip on the back of the plug.  Technically this is more like an O clip with a small break in it:)  To make things worse this sits in a groove to prevent movement.  Overall it is exceptionally hard to get off, it took me 20+ minutes the first time I tried.  The best method I have found is to try and get it completely out of the groove and then it is fairly easy to get off.  To do this I used small screwdrivers to pry one side up a bit, then used another screwdriver to slowly go around prying it up until I reached the other side, at which point i used a screw driver to pry this up some, and presto i was out of the groove (a good 5-10 minutes after).   I broke a mini screwdriver doing this, and doing it without damaging the clip is another trick.   You also may notice the pin in the back of the plug, this will come out once the C-clip is removed, and is there to prevent anything from coming out the back of the plug (can you say Adam Write Wires or a screwdriver!).

 
It is important to be careful while removing the plug from the cylinder (remember to put the key in, or manually bypass the slider to get it to remove easily).  Both the slider and the sidebar have small springs (two for the sidebar one for the slider) and losing these is very annoying (and somewhat hard to replace).  You may notice when taking the M3S apart that two crescent shaped pieces of metal fall out too, these are located at the front of the cylinder (see the picture on the right above for where one goes, the other goes next to it on the side).   These metal crescents are hardened steel to further prevent drilling.

 
This is the pin breakdown for both of the cylinders note the odd black color of the M3B bottom pins.  As we can see the M3B pins are just like standard cylinder pins, and are not effect at all by the angles on M3 keys.

 
On the left we have a mushroom top pin (found in both the M3B and M3S), it is a true mushroom pin and not just a spool pin as they frequently are.  Mushroom pins are used to try and prevent picking by causing the pin to false set on the sheer line.   On the right we have one of the hardened top pins from the M3S.

  
On the left here we have one of the more interesting M3B bottom pins.  It has a groove through the middle of it which we can only surmise is an anti-pick groove.  Frequently bottom pins may be serrated (American 5200’s) or have a groove similar to this but normally more towards the top of the pin.   It is very odd to have the anti-pick groove where it is, especially as the M3B is not said to have increased pick resistance (and would require some heavy over-setting to be effective) but it is the only function we can figure out for it.  In the center we have a standard M3S bottom pin, it is cut on an angle and has the groove running straight through the side of it for a finger from the sidebar.  Finally on the right we have the M3S bottom pin from another angle showing the metal nub mentioned earlier.

 
Here we have the two sidebars.  Both sidebars have two notches in them, these notches are what the two finger pins from the slider are able to enter.   The rest of the M3B slider is fairly basic, just the two springs, the M3S slider however features the 6 fingers that go into each of the respective pins (ensuring they are rotated the proper amount).

 
This is the side of each of the plugs respectively, where the sidebar goes.   The M3B plug has the slider in it showing the two fingers sticking up into where the sidebar goes.  If you look at the M3S plug you can see the 6 slots the fingers go through to reach the pins, if the slider was in the M3S it would also have the two fingers for the slider sticking up.

This is a top view of the M3S plug as you can see at the very front of the plug are 3 metal rods, these are anti-drill rods to protect the plug from drilling.

 
This is the slider, it is the same in the M3S and M3B and it is just showing it from two different angles.  You can see the two fingers which stick up into the sidebar and must be aligned into the holes in the sidebar to allow it to enter the plug.

 
Here we can see the sidebar just resting out of both plugs.  On the M3S you can see see the fingers sticking out.

This is with the M3S sidebar pushed into the cylinder if you look closely you can see the finger pins now protruding into each of the pin chambers.

Here we have a shot of the bottom of the M3S plug (you can see the fingers again here) which is where the slider is on both plugs.  As you can see there is a gap above the two notches in the sidebar where the slider fingers can move before the sidebar is pushed into the cylinder.

Once the sidebar is compressed you can see there is only the two holes for the slider fingers.  If the slider is not pushed in the right amount the sidebar cannot move into the plug as the holes will not line up with the fingers on the slider.

Here is a shot of the key in the M3S plug with the bottom pins in place.  It is easy to see all the grooves lining up and you can see the nub on the top of each pin.   The metal nub is basically used to ensure the pin does not rotate too much or else the key cuts would not be able to properly set it.  As you can see the nub sits in a small gap which allows it to rotate 20 degrees from the center both ways.

That concludes the breakdown of the cylinders, so lets take a moment to reflect on what we have seen.   First of all we know the M3B is basically the same as a normal cylinder with the addition of the slider (the sidebar is also new but is fully controlled by the slider).  This means that once you pick it like a normal cylinder you simply must slowly push the slider in while applying tension to get it to open.   As the slider doesn’t add much protection one may think the M3B is actually easier to pick then a standard Kwikset of Schlage due to the wide open keyway.  This is certainly partially true, however Medeco cylinders still are generally manufactured to tighter tolerances and do have two security pins in there, so it is still a hard pick.  Does this warrant the $40-70 list price? Maybe, maybe not.  You still get key control with the M3B and the ability to use the same keys for the M3B as you do with the M3S (good in mass deployments).  If you are going for anti-pick/drill ability your money is certainly much better spent on something like a Scorpion which can sell for roughly the same price.

Now onto the M3S, and how it stacks up against its cheaper predecessor the Biaxial.   From a picking point of view if you can pick a Biaxial (which is no easy feat on its own) the M3S will be no harder as the slider simply means once you are done with your normal picking you must push it into place.   Some may say it is easier to pick the M3S due to the more open keyway when compared to most Biaxials.    Don’t forget that while most locksmiths won’t willy nilly duplicate biaxial keys if you want true key duplication protection you should upgrade/buy the M3S.  

As long as you understand the M3B’s intended purpose (protecting nothing valuable but allowing the same key as the M3S to be used) and understand that security wise the M3S offers very little on top of the Biaxial (with the M3B being far worse obviously), you can make informed decisions about your lock needs.

Corrections
Recently Han Fey supplied some additional information in respect to this article.  Most importantly is regard to the groove I spoke about on some of the M3 BiLevel bottom pins:

Originally I stated that this was an anti-pick pin (similar to other serrated bottom pins) however the groove was too wide and low for a normal serrated pin, but no other purpose could be deduced.   Han Fey clarified their purpose: They are not to prevent picking but rather to stop decoding.   John Falle of Falle-Safe Securities makes several high security tools, including a standard pin tumbler decoder.  Most standard pin tumbler locks can be decoded by this tool and while I will not go into details on the tool, it is available to normal commercial locksmiths.  Medeco has taken the time to add this ‘falle groove’ to their BiLevel pins to make the BiLevel stand out from other standard pin tumblers.  If you look at all of the pins with this groove you will notice they are all equal distant from the bottom of the pin:

The second issue Han explained was that the BiLevel did not actually start with the M3.  For clarification, for the entire article up until this point, when I talked about the BiLevel, I was talking about the M3 BiLevel.  I had heard in the past that over seas the Biaxial had been called the BiLevel, this was not completely correct.  The original BiLevel is actually a very interesting modified Biaxial.  Some of the bottom pins are replaced with a special rounded pin (instead of a chiseled standard pin).  This rounded pin required the key to be cut by a special machine that can cut in 3D (if you consider the normal Biaxial key cutters 2D cutters).  This obviously greatly reduces the chance of key duplication and makes some other attacks harder.  This is not an article on the original BiLevel (although at some point on the future I may write one), however if you are looking for more information I was able to find some online at: http://www.medeco.dk/dwnload/Bilevel_brochure.pdf (See page 5 for a picture of the pin and key).  The original BiLevel obviously is of no relation to the M3 BiLevel, the original BiLevel may have been sold under another name in the US (if you know it please let me know).

I would like to thank Han Fey for providing the corrections and additional details.

The Abloy Protec lock is one of the most secure cylinder locks in the world.  It is currently the second most secure lock that Abloy offers, only superseded by the Abloy Protec CLIQ, which is the Abloy Protec with an additional electronic chip. I recently acquired a factory cutaway and figured how best to celebrate but to photograph and disassemble this beautiful beast. 
I would like to specially thank Jaakko Fagerlund, an Abloy expert, for not only direction on the breakdown but also technical review of this article.  If you are lucky enough to be going to the upcoming Dutch Open you will be able to catch him speaking there.  We have a lot to cover, so let’s get started…

 Abloy locks are disk detainer locks, and while small adjustments have been made to the system, the basic idea has stayed the same.  You have a plug with several circular disks in it, each disk has a small notch(gate) at a specific location.  In addition there is a metal locking bar that sits in a small cavity in the cylinder above the plug.  The locking bar is what is responsible for preventing the plug from spinning.  You insert a key with angular cuts into the plug and turn it 90 degrees.  This rotates the disks various amounts so that the gates on the disks line up and the locking bar can drop down into the plug.  At this point the plug can be rotated further to lock/unlock the lock.  For more details on how Abloy locks work I encourage you to check out Toool which has an excellent Abloy series by Han Fey, including Part 3 which focuses on the Protec.  I will talk about one additional feature of the Protec, just so those who don’t know will be able to follow the pictures, that is the return bars.  The return bars serve two main purposes: at rest or when the lock is opened they keep individual disks from moving (either due to physical movement during transportation or otherwise), they also ensure the disk return to their positions when the key is removed.  Two are required for this lock as it can be turned both ways, for more details see Han’s series.

I figure I would start with some operational pictures:

Pictures at rest: Key and lock | The return bars and bottom of the cylinder | Locking bar above the disks
  

Pictures at 45 degrees of rotation: You can see one of the return bars moving and disks spinning

After 90 degrees of rotation the locking bar may automatically drop into the plug due to gravity, however if it doesn’t then once tension is applied the slope in the locking bar groove will cause it to enter the plug.
Pictures : Locking bar dropped into the plug | Return bar has reached the other return bar and the disks are aligned
 

Pictures after additional rotation (unlocking the lock): Locking Bar in the plug | After about 280 degrees of rotation to the right | After left rotation instead of right
  

Now onto the fun of taking it apart! Before one goes about disassembling any lock you should make sure your workspace is clean, and you aren’t going to be interrupted by a phone call, an animal, or zombies.  The last thing you want is pieces to go everywhere or get out of order, especially on an Abloy.  In addition, if the lock you are taking apart is dirty some Kerosene, Acetone, Brake Cleaner, or Turpentine will allow you to clean your lock while taking it apart.

To start we need to remove the cam from the back of the lock. First we need to unscrew the cam, and then apply some pressure to pull the cam off. It is important make sure to do this with the back end up so the plug doesn’t come out.
Pictures: Cam Attached | Cam Removed
 

Next we need to remove the retaining clip that sits just inside the plug, I used a small flat head screwdriver(inserted into the lock bar notch) to do the trick. After this we need to remove a metal washer sitting behind it, a few taps to the cylinder while upside down should do the trick (again make sure to hold the plug in the cylinder while tapping).
Pictures: Retaining Ring | Retaining Ring Removed | Washer and Retaining Ring
  

Next we want to push the plug out a small amount so we can see the locking bar bracket and springs, I did this with the key in the lock, but you should just do it by pushing on the front of the plug slightly.  Once you can see the lock bar bracket you can remove it, and the two springs under it.
Pictures: Locking bar bracket and springs in plug | Springs still in plug but bracket removed | Springs removed
  

Next we want to pull the entire plug out, the locking bar may drop out at this point (or the silver profile disk), but don’t worry.  Tilt the back of the cylinder down and slowly push the plug out, making sure to hold it as it comes out as it may come apart otherwise. Once done set it down and set the locking bar aside.
Pictures: Entire plug outside of the cylinder | Locking bar aside with bracket and springs
 

If the profile disk did not come out during removal it is most likely stuck in the front of the cylinder, tap it until this comes out.
Pictures: Profile disk in cylinder | Profile disk removed
  

Next we need to remove the disk controller.  To do this put the plug vertically on the table, and slowly pull the disk controller off while holding the plug.
Pictures: Disk controller on plug | Plug with disk controller off | Disk controller on its face
  

Now I want to stop for a second and talk about the disk controller.  The disk controller is the only piece of the lock I did not fully disassemble, this is due to the fact I was told it came from the factory in one piece, and it did not come apart easily.  It also looked like it would be very hard to put back together due the springs, and the fact it may be partially crimped in place.  Aside from this the disk controller has two important functions. First ensures that the key is fully inserted before you can start rotating (as with Abloys without this feature you can rotate at any point which can prevent the key from being fully inserted or removed without rotating back to start).  Second it guides the key in so that minimal contact with the other disks occurs on entry, this helps avoid a disk spinning by mistake and blocking the keyway (along with reducing wear).  By using the dimple on each side of the key the disk controller can prevent premature rotation.  There are ball bearings that extend into the outer part of the disk controller when they key is not fully inserted preventing rotation.  Once they key is fully inserted the dimples on the side of the key allow the ball bearings to push into them, allowing for rotation of the plug. My key has two dimples per side, however only one is used by the Protec.  You can best see the ball bearings here:

Once removed we can now remove the front locking washer and return bars.  First remove the washer from the top, then you should be able to see the two silver locking bars. At this point you can flip the plug over (while holding the disks in place) and the return bars should drop out.
Pictures: Washer next to plug, return bars visible | return bars removed from plug
  

Next we need to remove all the disks, you can do this one of two ways, either by removing them from the plug housing, or by sticking the disk controller back through them, flipping it over, and doing it that way.  I did it the latter, but the choice is yours.  The important part is to keep the order and direction (facing up /facing down) of the disks correct.  If you do mix up the direction look at the pictures below, or know that all the disks go embossed side down during assembly.
Pictures: Disks on disk controller | disks placed in order on table (Top right disk is the disk closest to the back of the cylinder)
 

At this point everything should be disassembled; if your lock is dirty you can clean the metal pieces with your solvant now.
Picture of all the components:

Now to put it back together, this was certainly the hardest part, and is especially hard without the proper tools.  The tricky part is loading all the disks back in to the plug housing.  I will explain the way I did it, and then I will explain the way I think you should do it, and finally the way I received from an Abloy specialist.   What you should understand is that there are 3 types of disks.  Ones that have a single deep U gate in them, ones that have lots of small false gates and shallower real gates (generally two but sometimes one in the middle depending on the bitting), and finally ones with shallow gates but no false gates (that also look like they hug the key).  The first ones are primarily washers, the U gate on each of them interfaces with the locking bar and allow the washers to stay in place, the second work with the return bars and the locking bar, and finally the third are control disks used for moving the return bars.  You definitely want to align the first locking bar disks (so there is a straight groove for the locking bar).  I also believe you want to try and align the second type of disks for the return bars, however this may not be overly important(I have not tried without aligning these).  I thought the best way to do this would be to mount them on the disk controller with the key in the disk controller.  To do this I put the key in the vice (with some padding to avoid scratching) and used two things to align the disks: A) tweezers to align the locking bar groove (any flat piece of steel will do this) and B) a small flat-head screwdriver to rotate the disk once I placed it on the disk controller.  

I didn’t constantly use the tweezers just every now and then to ensure the groove lined up. At the end I used the return bars to help with their grooves, eventually I ended up with all the disks on.
Pictures: Key and disk controller in Vise | All disks loaded on key | Top shot with return bar

I then slowly put the plug housing on. The housing has a gap in the bottom of it; this should align with the first type of disks (ones with the locking bar gates).   Finally I loaded the last return bar in.
Pictures: Housing showing gap for locking bar | Loaded housing with both return bars

That was the way I did it, and it took several hours.  I would suggest trying to load the disks directly into the housing and not onto the key / disk controller first.  The housing keeps the control bar gates aligned, and then at a maximum it’s a matter of just aligning the other half of the disks and adding the return bars in.  You can manipulate the disks using a pin or small screw driver.   I would assume this should go much faster, but after spending a couple hours I didn’t want to take it all out to try again.  Finally A professional has provided that the way suggested by Abloy.  Abloy suggests you load the disks into the housing, use Vaseline or a wire tool to keep the return bars in place, and load them this way.  A picture of the wire tool:

After all the disks are reloaded and you have the return bars in you are over the hump.  Apply the locking washer back on top, then insert the disk controller.  Next reload the springs for the locking bar, and put the locking bar in its groove, place the profile plate on the end and slowly load it back into the cylinder.  Right before it’s all the way in, put the locking bar bracket on top, and push it the rest of the way in.  Now test it and make sure its working, if so put the cam back on and your done!