U-Change user-rekeyable lock breakdown

[Gordon Airporte]

I don't think these locks are very common, and they really aren't very secure. I just think the way they work is kind of interesting. The idea is that the user can rekey the lock without uninstalling it. All you need is a working key and some kind of special tool - neither of which I recieved with the lock, so this is all my reverse engineering and guess work.

That rectangular hole in the front is where the special rekeying tool goes.



Here is the plug, where all the action is. It's extra large - 11/16" in diameter, almost 3/4". Each pin stack has a rocker next to it.



At the top of this picture we see a driver pin, which is hollow, I guess to allow for the longer spring. I've stuck a pick in the lock to show the path the rekeying tool uses. At the bottom you can see two of the rockers and two of the variable key pins.



The variable pins have a spring loaded plunger which is held at a specific depth by a little tab. Note that even with the extra wide plug, the pins only have four depths.



The rekeying tool must pry in there and seperate the tab from the plunger far enough for the plunger to move freely. The problem is that the rockers covering the tabs are flush with the surface of the plug when the tab is engaged. There's no room for the tab to retract. See the pin on the right. Thus the plug must be turned 90 degrees clockwise so the nose of the rocker can protrude up into the driver chamber, this gives enough room to seperate the tab and adjust the pin. See the pin on the left.



So I think the procedure for rekeying is to open the lock 90 degrees clockwise with a regular key, insert a needle-like tool to pry the tabs out of the adjustable pins, remove the key, stick your new key in, remove the needle, and close the lock, pressing the tabs back in with the rockers as you rotate.

[Octillion]

The problem is that the rockers covering the tabs are flush with the surface of the plug when the tab is engaged. There's no room for the tab to retract. See the pin on the right. Thus the plug must be turned 90 degrees clockwise so the nose of the rocker can protrude up into the driver chamber, this gives enough room to seperate the tab and adjust the pin. See the pin on the left.

That's not a problem, it's so that the rekeying procedure is as you state it. Otherwise, you could just stick any piece of metal in there and screw up the keying of the lock.

Great post BTW, I was wondering how these work!

[digital_blue]

Fantastic post, and great pictures! Thanks for that! This is indeed an interesting concept.

db

[maxxed]

very interesting lock,thank you for posting it

[illusion]

Cool!

We're getting a good range of break-down threads on this forum. Nice work.

[HeadHunterCEO]

well done

the rekey tool is a small piece of spring steel the size and shape of the port on the front of the lock .

it has a 45 degree point on the front. as you push it into the lock it pops the set pins clear

[raimundo]

Wheres Chucklz? I think he should see this.

[mh]

Great post!
It could go here as well, for easy reference:
viewtopic.php?t=13478

And yes, where is chucklz?

mh

[Gordon Airporte]

Thanks everyone!
Thanks for confirming what the rekeying tool is HeadHunter. I'll probably make one, but since I can't make keys there's only so much fun to be had there.
Octillion is right that the way the rockers fit is a security measure. It was a problem for me because I didn't figure it out right away. Even if you can't mess up the code without a key, it's still pretty simple what you need once you have one. I guess I'm comparing this to i-core locks where you need a real key and not a simple metal stick to change things. Of course, these can't be master-keyed, so the applications end up being different, and so do the security concerns. The only one of these I've seen in the field was on the front door of a retail business.
A locksmith that sells you one is giving up some revenue I guess. Then again, he still has the key cutter.

[raimundo]

If you look it up on google, they even say on their website what chain stores use them.

[Chucklz]

I'm glad someone finally has decent pictures of this lock up. My cam can't do crap for maco. When taking these things apart, be VERY careful with the bottom pin assembly, as they tend to fly apart.