Medeco padlock breakdown

[Squelchtone]

You said it is a 4 pin Bialial. Does that mean it has the rotating pins?

This is a very common belief. I think from about 1999 to about 2005 I thought Bi-Axial meant having 2 axis movement which meant up and regular pins moving up and down to create a shear line, and rotational movement to match up the angles so the sidebar would fall in.

I still don't know if I fully understand the naming scheme they came up with, but before M3, and before Biaxial, there was Original, and they were also pins you had to lift up and down and rotate in order for a sidebar to fall in.

In effect, other than a newer Medeco model called the Bi-Level, which is a lower security lock needing only the pins to be lifted to a proper shearline, and an M3 slider to be positioned correctly, all other generations of Medeco incorporate lifting and rotating pins.

Original Medeco from 1968/1970/73 to 1985 had no other logo other than the word Medeco and the UL 51s. In 1985 there was a large Biaxial logo to help users distinguish the new model. From what I have read Biaxial was intended to help generate many more key differs in large master keyed systems and it also helped extend the keyway and rotating pin patents for Medeco, making restricted keyways a selling point. The most recent flavor is M3 which as proved by the locksport community doesn't offer much in terms of added security, but certainly helps with key restriction and patent extension. Going back to biaxial though, if you were to look at the chisel tip of a biaxial key pin, you can have either a fore or aft pin chisel, which means that you can have more cuts on a key, more combinations, and that's why it was so good for grand master systems. the Original Medeco pins only came in Left, Center, or Right angles. When Biaxial came out they came out with 6 pins! 3 fore and 3 aft of the Left, Center, and Right variety. I'll try to dig up some pics and docs because I'm sure someone here has written it up before and I dont want to muddy the waters with my own version of an already much covered topic.

Here is a run down of Medeco cylinder logos over the years. Please note, 51s is not the model number. most of the cylinders are 10-0200. 51s is a UL number given to Medeco rim and mortise cylinders after they passed UL 437 testing.

Large image ahoy! dont worry its only 120kb





-Squelchtone

and yes. I own a 1970 Medeco cylinder. frickin awesome. =)

[Safety0ff]

This is a very common belief. I think from about 1999 to about 2005 I thought Bi-Axial meant having 2 axis movement which meant up and regular pins moving up and down to create a shear line, and rotational movement to match up the angles so the sidebar would fall in.

Although very common, when you look at the meaning of that interpretation, you can see that it's false: 1)The rotation of a pin happens in the same axis as the lifting! 2) You have to generalise that you have one axis for all of the pins!

A sidebar's motion could be view two ways: relative to the plug (moving inwards along one axis,) or relative to the shell were it moves towards the center of the plug along an arc.

So in a 6 pin lock with a sidebar you've got 6 axis for the pins, 1 for the plug (which will be the same as the key,) and with the sidebar you've got one axis (if you look at it's movement relative to the plug.)

Note that Bilock sidebars (once again, movement relative to the plug,) operate in the same axis.

All of this assumes perfect tolerances.

[hydruh]

Wow, Squelchtone, that was one hell of a writeup. Thanks!

This is the best hobby ever!! <snif>

S

[PinPopper1]

Really great write up squelch. Very thorough.

[IndigoChild]

I am a dealer of Medeco Locks and BiAxial means that the pin spacing can be offset back or forward.
In other words instead of having a nice uniform key

. . . . . .

you have something more like this

.. .. ..

The spacing in the plug and cylinder is exactly the same, but there are a whole lot more pins to to choose from when rekeying.

The medeco M3 has the addition of a second set of bitting on the side of the key like a Kaba lock.

I hope I didnt re answer this, but if I didnt I hope this helps.