Hi Lenny Try here http://www.whitechapel-ltd.com/hist/locks.shtml ----- Original Message ----- From: "Lenny McHugh" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Friday, December 28, 2007 6:49 AM Subject: Re: [BlindHandyMan] Historical Guide to Cabinet Locks
> Ray, what is the source of this information? > > ----- Original Message ----- > From: "Ray Boyce" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Thursday, December 27, 2007 3:22 AM > Subject: [BlindHandyMan] Historical Guide to Cabinet Locks > > > The need to secure precious objects is so innate to humans and many other > animals that it is not surprising the earliest locks appear as long ago as > 4000 > years. The oldest known locks employed a pin tumbler mechanism much > like > that of our modern "Yale" lock but on a far larger scale. They have been > found > in cultures as diverse as those of Egypt, Japan and Norway. The Romans can > be credited with the invention of the metal lock and in fact developed the > "warded > lock" which uses the familiar skeleton key still common enough today. > Warded > locks rely on sections of concentric ridges around which the key must fit > in order for it to act on the locks sliding bolt (see diagram below). Time > passed and the increasing complexity of these locks became a source of > much > pride to the locksmithing profession and some misplaced assurance to the > person with much to protect. Of course the lock picker was never far > behind > these > advances and being engaged in a prideful profession demanded job > satisfaction only more advanced locks could provide. The late 18th century > gave him a > more challenging device, the double action lever lock (see diagram below). > This mechanism is found in most furniture grade cabinet locks today. As > the > key slides the bolt into or out of the lock it also moves one or more > spring > loaded levers away from the bolt's path. The more levers, the harder the > lock > is to pick. > > Warded lock > > Lever lock > > Today > > Today the use of locks on furniture has become somewhat redundant. In > earlier times locks in the domestic realm were intended to frustrate not > outsiders > but children or those in the employ of the household. These days a locked > drawer might deter a passing child but the real predators are more likely > to > come from outside and rarely have the time or interest to develop skill in > the craft of lock-picking. Their modus operandi more likely involves the > use > of wrecking bars etc and in any case they might realize the contents of a > nice piece of furniture is in all likelihood of less value than the > furniture > itself and simply abscond with the whole thing, locks and all. Whether > they > serve any practical function or not, we have become so used to seeing > locks > on fine antiques that a drawer without one seems as blank as a face > without > a nose. > > In many situations the key of a lock served as the handle for a door or > drawer while the lock itself took the place of the catches we are so > familiar with > today. Aside from the finger turn type of catch the 18th century was > remarkably short on door catch technology so the lock would find > application > wherever > a door needed positive closure. Today we like the convenience of our > magnetic and ball type catches and often wish to use then on reproduction > style cabinetry. > Attempting to find an appropriate knob or handle to take the place of an > escutcheon and key is no easy matter and leads many otherwise respectable > cabinetmaking > efforts to fail needlessly. It will always be worth the extra effort to do > the job right and fit a lock. > > Choices > > Traditional cabinet locks are available in an array of mounting, material > and size choices to suit most preferences. Three alternative mounting > configurations > are the " > Half Mortise", " > Full Mortise" > and "Surface Mount" style lock cases. The "Half Mortise" lock is the one > found on almost all fine English and American antiques prior to the middle > of the > 19th century. This type of lock is mortised into the back side and edge of > the work and lays flush. The "Full Mortise" lock is mortised into the edge > of > the work. The "Surface Mount" lock is simply screwed to the inside face of > the work. Each of these types has its advantages. > Terms > > The various names for the parts of a lock and the definition of a left or > right hand lock are a source of endless confusion!. Here is our glossary. > (Beware: > our definition of left and right hand are the opposite of some others, > including even our own lock manufacturers!) > > Bolt - When you turn the key the bolt is the part that projects out of the > lock. > > Selvedge - The face of the lock through which the bolt projects. > > Plate - The face of the lock onto which the mechanism is attached. > > Distance to pin - The measurement from the selvedge to the center of the > keyhole. > > Backset - The same as distance to pin. > > Full Mortise - A lock whose body is entirely mortised into the wood. > > Half Mortise - A lock mounted into a shallow mortise in the back of the > work. > > Surface mounted - A lock that is screwed to the back of the work with no > mortising required. > > Left Hand - A lock mounted to a door hinged on its left hand edge (or the > reverse, depending on where you get the lock). > > Right Hand - A lock mounted to a door hinged on its right hand edge (or > the > reverse, etc as above). > > Levers - Spring loaded obstructions that the key moves out of the path of > the bolt. The more levers the more difficult it will be to pick the lock. > > Half Mortise Locks > > Half mortise lock The half mortise lock strikes a good balance between > ease > of installation and unobtrusive utility. The work necessary to fit these > locks > makes greater demand on finesse than muscle, all the cuts are of the wide, > shallow nature rather than the more problematic narrow, deep variety > demanded > by the full mortise lock. This attribute suited the pre-power tool > cabinetmaker. Because the half mortise lock is always registered against > the > inside > surface of the work the bolt is biased to the rear. Traditional > cabinetmaking accommodated this rearward bias with casework drawer > dividers > constructed > of sufficient width material. In modern face frame construction this > characteristic can lead to problems and either the full mortise or surface > mounted > lock could be a better choice. > > Half mortise locks were rarely paired with a strike plate. The bolt of the > lock would engage into a simple mortise cut directly in the adjacent > woodwork. > Aside from the remote possibility of catastrophic wear taking place there > is > no downside to this method. Strike plates serve no useful purpose and cost > the cabinetmaker time and money. > > Due to the internal mechanical layout of the half mortise lock the key is > invariably off center in relation to the lock body. Before laying out the > cuts > for these locks take note of this fact! > > Full Mortise Locks > > These locks were virtually unknown before the days of mechanized > woodworking. Because a full mortise lock is fitted into a deep mortise > Full mortise lock cut into the edge of the work it is troublesome to > install > without a mortising machine, with one it could hardly be easier. The > reverse > is true of the half mortise lock. > > Though conceived with rapid and mechanized installation in mind they are > not > without some drawbacks. The bolt will generally be centered in the work > rather > then biased to the rear as in the case of the half mortise lock. This may > result in certain benefits related to constructional simplicity but also > brings > the bolt nearer the front of the casework making it more likely for that > area to break out under force (a strike plate can compensate by > reinforcing > this > area). > > A full mortise lock can also be a problem installed in thinner material. > For > any given lock thickness a full mortise lock will leave two walls half the > thickness of the one wall left by a half mortise lock. An additional minor > consequence of this forward positioning is the attachment of the keyhole > escutcheon. > Keyhole escutcheons are normally attached with brass escutcheon pins. If > the > wall thickness left after the lock mortise is cut is limited then these > pins > will have little to secure themselves to. > > As with a half mortise lock, the keyhole is off center in the lock. > > Surface Mount Locks > > Surface mount locks are simply screwed to the back of the door or drawer > front, no cutting required. Most surface > Surface mount lockmounted locks have a dual keyhole allowing them to > function as both hands of door lock as well as a drawer lock. The keyhole > is > usually > centered in the upright width of the lock and the bolt can exit from > either > side depending on which way the key is turned. > > The bolt of a surface mount lock will engage behind the adjacent face > frame > or door to prevent opening. > > These attributes make surface mounted locks versatile and popular, but > like > many things easy and convenient they are not going to impress anyone with > their > refinement. Surface mount lock appears to have historical credibility on > country styles of furniture particularly as door locks but should probably > be > avoided on more formal work. > > > > To listen to the show archives go to link > http://acbradio.org/handyman.html > or > ftp://ftp.acbradio.org/acbradio-archives/handyman/ > > The Pod Cast address for the Blind Handy Man Show is. > http://www.acbradio.org/news/xml/podcast.php?pgm=saturday > > Visit The Blind Handy Man Files Page To Review Contributions From Various > List Members At The Following address: > http://www.jaws-users.com/handyman/ > > Visit the archives page at the following address > http://www.mail-archive.com/[email protected]/ > > If you would like to join the Blind Computing list, then visit the > following > address for more information: > http://jaws-users.com/mailman/listinfo/blind-computing_jaws-users.com > > For a complete list of email commands pertaining to the Blind Handy Man > list > just send a blank message to: > [EMAIL PROTECTED] > Yahoo! Groups Links > > > > > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.17.9/1197 - Release Date: 12/25/2007 8:04 PM
