Terminology and Summary of Lock Types & Security

[dry132]

Okay guys, I have a few basic questions just to explicitly clarify some terminology and a few of the more basic (and probably assumed to be widely known) aspects of LP.

1.) What, exactly, is a mortise lock?

I've seen conflicting definitions around the web, and wonder which one is "commonly accepted" on lp101. As I understand it, this type of lock is one that fits into the door, flush with the door in a rectangularish hole, as opposed to a dead-bolt type lock. Is that correct? or is there more to the story.

2.) On a mortise lock (as pseudo-defined above), is the mechanism requird to be of a particular type? i.e. levers or pins-tumblers (or anything else)? Or can it be any mechanism so long as it fits in the mortise lock frame, flush in the door?

3.) What makes a lever-lock more secure than a pin-tumbler type lock? I'm from the USA, so I have not yet gotten to play with a lever lock. It seems like they would, if anything, be easier to open... but I hear that this is not the case, and wonder what exactly makes them more "high security". I have to admit the keys look pretty funky, too.

4.) Are worn locks supposed to be easier or harder to pick? In the brand-new practice locks I've acquired it takes about a minute or two to pick them, but with the worn locks on my house the locks practically pop open as soon as the pick gets in the keyway. Is this normal and expected of most worn locks? They are all pin-tumbler style, similar quality locks.

[digital_blue]

This is what I get on mortise lock:

Definitions of mortise lock on the Web:

A square box--mortised into the door--that contains the mechanism (sometimes a variety of mechanisms) that opens, closes, and locks a door. Mortise locks are manufactured for interior and exterior doors. Both types of mortise locks are available in a variety of functions.
www.lahardware.com/glossary.html


A lock fitting a rectangular shaped cavity in the edge of a door. A round hold in the face of the door receives a spindle to which knobs or levers are attached. If key operated, a second round hold above the first receives the cylinder(s) and thumbturn. Some functions use two cylinders which is not a violation of the codes because the inside cylinder locks and unlocks the outside knob and the inside knob always operates. Some functions use two cylinders which sometimes is a violation of codes because the inside key projects a deal bolt or locks the inside knob which can only be unlocked by key. (This example of key operation on the inside applies equally to other types of locks and is mentioned under mortise locks only because it originated with them).
www.arrowlock.com/glossary/typelock.html


A locking latch mechanism that requires a rectangular hole in door edge for installation. Ubiquitous in pre-1940 homes, this type of lock is known by many other names.
www.rejuvenation.com/faqnumberid3c18d73 ... qshow.html

I will let somebody else andwer about the lever locks, as I am also in North America and have not ever had the opportunity to play with a lever.

As for the worn locks being easier or hard, it depends. Picking is generally made easier by greater tolerances in the lock. As pins and pin chambers wear, the tolerances will increase, so in some cases, and older lock is easier. The flip side is that older locks can get "gunked" up making them tougher to pick.

There's my half an answer. Somebody else, I'm sure, can fill in the blanks.

db

[Romstar]

Well, a mortise is a hole. What makes a mortise different is that it is a "blind" hole. It doesn't go all the way through. So just sort of work from there.

A mortise lock must be installed in a hole in the door. Typically, when discussing locks, the mortise will be in the edge of the door shaped to accept the latching mechanism.

Bear in mind that when speaking of "locks" as mounted on/in the door, there are actually two parts. The first is the lock or cylinder, the second is the latch or bolt which is activated by the lock.

In a pin tumbler mortice lock, the cylinder has a cam attached to the rear of the lock. Once the cylinder has been turned, either by picking or by the proper key the cam interacts with other mechanical components in the mechanism to retract or throw the latch or bolt.

In a lever lock system, the "lock" is actually a part of the mortise latch or mortise bolt, and the key itself interacts with the bolt. In a typical installation, once the key bitting has raised all the levers to the proper positions, the bolt stump can pass the gates in the levers and the key interacts directly with the talon in the bolt, throwing it open or closed.

By way of contrast, a RIM cylinder or night latch is mounted on the inside of the door, and the cylinder is inserted into a hole drilled through the door. The rim cylinder or night latch has a strike that is mounted to the door frame as opposed to being mortised into the frame as is typical of mortise deadbolts, latches and comon key in knob locks.

I hope this help clarify the situation.
Romstar

[MrB]

Oh, Romstar got there while I was writing a reply, so I'll just delete my words on the subject...done.

I had one thing to say that doesn't seem to repeat anything Romstar said:

Lever locks are not necessarily more secure than pin tumblers. A basic three lever lock can be as simple to pick as a cheapo Master lock. The more expensive lever locks are made harder to pick by having more levers, a curtain, and anti-pick notches. The curtain works by severely limiting access, so you need special tools to get in there and manipulate the levers while tensioning the lock.

Lever locks are found on safes and safe deposit boxes too. Those locks tend to have many levers, like maybe ten, compared to three, five or seven on door locks, but the basic picking technique is the same.

[vector40]

I guess lever locks are secure mainly by way of "security by obscurity," at least in the US -- nobody really knows how to deal with them, so they can't.

I usually find well-worn locks much easier to pick, especially by ripping or scrubbing techniques -- sometimes they can pick great with large amounts (relatively speaking) of tension, too, which is a neat change. As db says, the other side of the coin is a lock that's not just comfortably worn, but rusted, weather-damaged, or clogged with something, in which case you'll probably have more trouble than normal.

Rom, when you talk about the rim cylinder, do you mean something that looks like this? http://img.photobucket.com/albums/v201/ ... /mica1.gif

[Romstar]

You got it Vector, that is indeed a Rim or night latch.

There is a varient on it, in that you can get the sort that does not automatically lock, and requires you to turn the key in order to throw a dead bolt as opposed to a spring loaded latch.

Romstar

[vector40]

Neat... you mean you need to turn a key on the inside to lock it, as well as outside?

By the way, are locks that secure the "head and foot" mechanisms (where you've got a vertical configuration through the door -- when you push the latch, bolts withdraw from the top and bottom of the door) considered mortises?

[dry132]

So basically a Mortise deadlock differs only in the way it is mounted from a traditional residential "US-style" deadbolt. But a Mortise deadlatch has both a knob and a keyhole, and also mounts differently. I can infer that a "Mortise Lock" makes no reference to the locking mechanism, be it tumblers, levers, laser-cut, dimple-key, or any other mechanism so long as it fits within the Mortise style door cut.

Another question now: Why are mortise locks considered higher security than a knob/deadbolt pair? It seems all the banks, hospitals, and fancier office buildings around here use them.

[Romstar]

No, it isn't always necessary to turn a key on the inside to lock the bolt. In some places now, locks of that nature are actually against fire codes and life safety codes and can result in the owner facing fines for having them.

However, in any case where a deadbolt is used, it almost always must be manually thrown. Either by a thumb turn from inside, or via the key from the outside.

As for your other question, if the bolt mechanism is in a pocket or mortise in the door, it too can be considered a mortised type lock. Bear in mind that the definition is related to the type of hole. The term actually comes from construction/woodworking where a mortise and tenon joint is used. The mortise is the blind hole made to accept the tenon in another piece.

Typically though, when refering to a mortise lock, we are discussing the more common type and we can say that a lock similar to what you have described has been mortised in.

Its a fine distinction, but for the sake of clarity, we tend to apply the terminology in a more general manner.

I hope that made sense.
Romstar

[Romstar]

So basically a Mortise deadlock differs only in the way it is mounted from a traditional residential "US-style" deadbolt. But a Mortise deadlatch has both a knob and a keyhole, and also mounts differently. I can infer that a "Mortise Lock" makes no reference to the locking mechanism, be it tumblers, levers, laser-cut, dimple-key, or any other mechanism so long as it fits within the Mortise style door cut.

Another question now: Why are mortise locks considered higher security than a knob/deadbolt pair? It seems all the banks, hospitals, and fancier office buildings around here use them.

I get done one answer, and I have another one to do.

You are basically correct in that the term mortise does not refer to the mechanism, but rather to the method of installation.

It is considered more secure because it is installed directly into the door, and when properly installed can actually be stronger than mounting the hardware on the backside of the door. The door material, be it wood, steel or aluminum is actually reinforced by the lock being installed into the door.

In a kick-in attack, the lock is far less likely to be broken away from the door, and the door itself is far less likely to splinter or break. Assuming the installation was done properly.

I hope that helps.
Romstar

[vector40]

Thanks for your time, Rom; you're our locksmithing hero

[dry132]

Yeah, Rom, that helped a lot. I wanted to make sure I had the terminology right so I can understand some of the posts better, and you pretty much cleared it up.

[vector40]

Resurrecting this thread to avoid starting a new one... sorry for the Frankenstein, lads.

Can anyone tell me what you'd call the sort of latch system, pretty common on older residential front doors around here, where the lock is mounted above a vertical handle which uses a thumb button to open? Sort of the equivalent of a key-in-knob... except it's not a knob... and the cylinder's above it, not in it. It is, however, all one mechanism; the lock does keep the thumblever from depressing, it doesn't throw a bolt or anything.

[digital_blue]

If I am thinking about the same devices you are I believe handleset is the correct term for those. I have also heard them referred to has gripsets.

Check these out to confirm we are talking about the same thing:
http://www.weiserlock.ca/wei-eng/handlesets.htm

db

[vector40]

That is actually it. Thanks, db.