"Best" lock won't set in locked position [photos]

[Jay J. McCool]

I acquired an old lock, I think it was removed from a dormitory door, probably when the lock was re-cored or something like that.

Something that boggles me is that when I pick it in one direction it turns 180 degrees and stops (which sounds like the "wrong direction" according to Ted the Tool) but when I pick it in the other direction it rotates a full 360 degrees and sets in the "unlocked" position - that seems equally, if not more, unusual. Because of the full rotation (which sets the lock back in the unlocked position after picking) I can pick the lock limitlessly and continuously in the same direction, and it always ends up unlocked - never setting in a locked position.

Enclosed are pictures.

[devildog]

Best SFIC

[Stylefree83]

must be an old lock my grandmothers 60 yr old house has a lock on her doors that set in the unlocked position

[Jay J. McCool]

Best SFIC

So what does that mean? Do Best interchangeable locks only work properly (i.e. set in the locked position) when in place on a door?

[vector40]

No. I'm not sure what devildog's point was. He was just identifying the cylinder.

Do you mean that it rotates 360 degrees (a full turn, ending up where you started) when you pick it? Or 180 degrees as you said, which would leave the plug upside down?

[TOWCH]

Unless the top pins are getting stuck in the keyway, and it needs to be turned farther, it sounds like the problem is with the latch or tail piece. If you're not sure if it's the first one, when it stops on the 180, use the back of a half diamond pick to lift up any driver pins that might have fallen in the keyway, and try and turn it farther. Otherwise, you need to strip down the lock and figure out why it isn't engaging the latch.

Edit:
From your description it doesn't sound like a top pin problem, and my guess would be the same as zeke's. If the bolt retracts when you turn it the 90 degree direction, then the lock is fine. If it won't retract no matter what you do, then see "Otherwise, you need to strip down the lock and figure out why it isn't engaging the latch."

[Stylefree83]

the one i was talking about you have to turn 360

[zeke79]

It appears to me to be a dead latch. This will operate similar to a deadbolt but allows the user to simply close the door or gate to lock it. The key is then used to turn the cylinder to retract the latch but when the key is returned to the neutral position the latch is fully extended outward. The only function that they accomplishes is temporary retraction thus it cannot be permanatly unlocked. Though some older yale deadlatches that I have worked on allow the user to use a thumbturn on the inside to retract the latch and depress a button on top of the thumbturn assembly and lock the latch in the open position. Some of these latches have the flaw of being able to retract the latch as one would on a standard key in knob latch. I hope that makes some sense as I am barely awake right now.

[Jay J. McCool]

Do you mean that it rotates 360 degrees (a full turn, ending up where you started) when you pick it? Or 180 degrees as you said, which would leave the plug upside down?

My bad! Yes, I mean it turns a full 360! When I turn it the "wrong" way (it locks, but won't set) it's 180 degrees, not 90.

[vector40]

Okay, when it's stopping at 180 degrees, I would guess that the driver pins are jamming into the gap at the bottom of the plug. You can lift them out with a straight back of a pick (or whatever) and keep rotating, probably.

[Jay J. McCool]

It feels like that could be the case - that some pins are getting stuck and holding the lock from further rotation.

Anyone have some diagrams that might help illustrate what's happening here? I don't fully understand the mechanics.

[vector40]

No diagrams, but it's pretty simple. The entire bottom of the keyway (the empty space the key moves through) is open, an empty gap. That's just part of the manufacturing process, and when the key is inside, it's filled smoothly, so there's no problem. But when you're picking, that gap is open, so when you turn the plug 180 degrees, the top pins can fall into that space. They won't fall FAR, since it's not a big gap -- not enough to actually come out or anything, which would be disasterous -- but they'll often wedge in a little bit with their beveled tips, enough to stop the plug from turning.

If you stick something -- usually we turn over a pick and use that, since you'll get a straight, flat edge -- into the lock when this happens and use it to lift all of those driver pins evenly, you can usually just get them out of the way and keep rotating.

[raimundo]

I suggest that we use the terms 'clockwise' and 'counterclockwise' to speak clearly about rotation direction. The cylinder you have is an ordinary best type of lock, but the backside where the cylinder ends and the boltworks begin is the likely the reason for the mechanical stops. Vector 40 is right about the top pins falling into an empty keyway when that bottom of the slot is turned upward, however, some very thin masterkey pins can in fact fall out if they are present. Best uses such thin masterwafers. This does not mean that you will have the problem, but it is possible on some locks and is something to be aware of.

[Jay J. McCool]

I'm not sure I understand correctly - I've inserted a pick to hold up the driver pins in their normal position, but the lock still won't rotate clockwise past 180. At the 180 clockwise mark, the bolt will be locked, but the lock won't be set (no springs pushing driver pins, so any torque applied counterclockwise will allow the lock to return to unlocked position, where the springs will push the driver pins back down and set the core in place.)

More pictures, can ya tell me if I'm doing this right?

[Shrub]

The springs are pushing the top pins down in to the bottom of the keyway which has now been turned to the top, you have your pick in the wrong side on the last photo, put it at the bottom of the keyway which is now at the top and push the top pins back against the springs and out of the bottom of the plug.