While I've looked around the Internet, and many people claim to pick these, I've yet to find a single account of someone describing in detail how to pick a Medeco lock. This method works just the same on older Medeco locks as on Biaxial, and the newer M3 which requires one additional but easy step.
To pick, I use a short hook, and a normal torque wrench placed at the top of the keyway on the pin side, with a short tab so that it does not touch the first pin.
The first thing to do is pick the pins to the sheer line. When doing this for the first time you may keep the pick relatively centered on the pins, in the hopes that the angle of the pins are already close to their correct rotation. In many locks the rotation of some of the pins will seem to just set themselves, and the lock will actually open rather easily. It is also easier to feel out the lock for the first time if you don't have to think about pin rotations. If picking in this manner proves ineffective later, you may try angling the pick to the right (for example, but the left works just as well), and pull back on the side of the pin as you lift, so that the pin rotates to the right as you set it to the sheer line (that is, the right side of the pin will be pulled towards you).
You must make sure you pop up all mushroom pins above the sheer line before moving on. Mushrooms will feel slightly different as you pop them above the sheer line than standard drivers do when they are set. I'm not sure I can explain it well, but if you push a pin up and feel it hit the sheer line, pushing it up a little more will cause it to pop up once again if it is a mushroom, and then it is set. If the driver is not a mushroom, when you push it up more you will just feel the bottom pin being over lifted, and you will have to reduce torque to let it fall back down.
Once everything is lifted to the sheer line the plug may rotate a bit. If it does not, wiggle each of the pins lightly until it does, while feeling to making sure that each pin is actually at the sheer line. This will align the gates (both true and false) in the pins to line up with the fingers on the sidebar. Once the sheer line is set, and the sidebar fingers line up with gates, the plug will rotate a bit, and at this point you will be able to work on the sidebar. If you are lucky the lock will open this moment. It does happen, but rarely, so don't count on it. More likely, one or more of the pins is set in a false gate.
Once the sidebar fingers have aligned with gates, apply heavy torque and wiggle the bottom of the pins. Pins that are falsely set (in a false gate) will have pressure put on them by the sidebar, so they will be somewhat stiff, while pins that are in the true gate will be free, as the sidebar fingers do not apply pressure to the true gates (actually, some of the pins that feel free might only feel free because some other falsely set pin is taking the brunt of the force from the sidebar). This part is actually quite easy.
Now the pins that are set in false gates will need to be rotated. If you tried picking all pins to the one side, it may be wise to try and rotate the pins with falsely set gates to the opposite side. It is useful to try to feel for how the pin is actually oriented. This is a bit difficult, and I am still working to perfect it, but it is possible to read the pin rotations. Place the hook behind the chisel of the pin you wish to read so that it is on the slant. Rock the pick back and forth axially; preference to which way the pick rocks will indicate the pin rotation. Center rotated pins should show no preference. Being able to do this properly is very difficult, and easy to misread, but it does work and may be helpful in being able to pick these locks.
Once you know what pins need to be rotated, start picking the chisel of the pin back, with the hook slanted to the preferred orientation, while slowly easing up on the heavy torque to release the sidebar finger and allow the pin to rotate. Periodically increase torque to check if the pin has been rotated properly. This may take several attempts. Be careful not to push up on the pin too much as this may over lift it, causing other pins to fall. It is easy to lighten up on the torque too much, causing some of the pins to fall below the sheer line. If this happens, just re-pick the lock, this time picking the falsely set pins to the opposite rotation (if you think you know how it was previously set) so that you hopefully wont have to deal with them next time around. If you manage to rotate the pin to the correct orientation without dropping other pins below the sheer line, either the lock will open, or you will have to deal with another falsely set pin.
You may find that the plug actually rotates a bit more when working on the sidebar, then jams up again. This is a mushroom you missed, and your going to have to pop it up there, most likely dropping a lot of pins below the sheer line with it. It's important to pop all the mushrooms up as soon as possible, otherwise they will screw you up later.
In some locks the sidebar will bind before the sheer line. When this happens, you will notice that none of the pins seem to bind to the sheer line, but when heavy torque is applied to the plug a few pins show some resistance. When the bottom of these pins are wiggled with torque applied, they will be stiff due to the sidebar finger hitting a false gate. Release torque and rotate the pin, then reapply torque and repeat until the pin is no longer bound by the sidebar. Look for any other pins bound by the sidebar, then proceed to pick the sheer line.
For Medeco M3 locks, once the pins are set and it feels like the pins are at the correct angle, simply press in the slider with your pick. The slider is spring-loaded, so if everything else is set correctly, you will feel resistance to pressing in the slider, and once the slider is pressed in far enough the lock opens. If something is binding elsewhere in the lock the slider will feel springy, indicating the lock is not correctly picked.
- Pick pins to sheer line, popping up mushrooms ASAP. In some cases, you may have to rotate some pins if the sidebar binds before the sheer line.
- Pick sidebar, by reading for false gate set pins, and rotating them.
- If you mess up while picking the sidebar, pick the sheer line again remembering the how the pins should be rotated from what you learned when picking the sidebar.