Mortise Lock Straight Talk!

With Xavier Blaine

Oh, the front door…  It is the most evocative feature of every home, a thing of both beauty and security, a silent sentinel of architectural devotion.  Its intricate carvings or stark panels, the comfortably oversized knob and backplate, the swing of the hinges, even the species of wood, all were carefully considered to create that most engaging of thresholds.  In truth, what good would a home even be without a good front door?  And yet the most important feature of every door, its entire raison d’etre, is not even visible, for what good would a front door be without a good lock?

Designed as a complex of springs and levers, hubs and stops, the exterior mortise lock is one of the most intricate, perplexing and critical pieces of hardware an old home owner will ever come up against.  If any part of the lock fails, one can quickly find themselves in urgent need of its repair or replacement.  But the array of arrangements, the numbing amount of possible configurations of stops and springs and bolts and latch placements, is truly, utterly, both wondrous and stupefying.  If that’s not daunting enough, keep in mind that your front door, your uniquely beautiful symbol of domestic security, has been custom cut to fit just one of the seemingly infinite possibilities of exterior mortise locks and if you fail to get your old lock working or can’t find its exact replacement, you risk needing to rearrange or replace the knobs and doorplates.

But fret not curious reader.  The century old lock that has been your unacknowledged source of safety and sanctuary can be fixed, it can be replaced and it can be made to work again for another century or more.  In the interest of educating the public on the oft overlooked niche field of mortise lock preservation, we at Historic Houseparts thought we’d dig through our comically oversized canvas mailbag and publish mortise lock related correspondence for your troubleshooting pleasure.

Dear Xavier:  Help!  I was headed to the farmer’s market and brushed against the edge of my front door with a reusable grocery bag.  I realized I forgot my grocery list and turned to head back inside, but all of a sudden my outside doorknob won’t turn!  Did I break my lock somehow?   Cordially, Locked out in Lockport.

Dear Locked Out:  You did not!  Put your key in the cylinder, turn, and push.  Your door will open!  The bonus prize is that your lock is working exactly as it should, though it may not seem that way at the moment.  You’ve encountered a quirky, albeit frustratingly superfluous, feature found on a lot of older residential locks.  If you look at the faceplate of your lock, you’ll notice two buttons, or sometimes a sliding brass tab.  These are classified as “stops” in the terminology of locksmiths and are essentially a toggle switch.  Depressing one of the buttons moves a bar that blocks the movement of the exterior knob or thumb latch.  Depressing the other button reverses the effect.  If you’ve disabled the exterior knob with this switch, either by accident or design, you will absolutely need the key in order to move back the latch bolt and regain entry to your home.  So, why does this feature exist?  Honestly, I’m not entirely sure.  One would imagine it’s an evolution in lock security to overcome some shortcoming in design, or to thwart the throngs of Victorian era street urchin lock picks.  But it also might have a more mundane explanation.  Those stop mechanisms allowed lock manufacturers to sell a single lock that could have multiple applications with the simple push of a button.  If one button is pushed, you have a quality lock for residential buildings.  Push the other button, and you have a quality lock for commercial or apartment buildings where limited access is more desirable.  On a related note…

Dear Xavier:  We recently acquired a historic farmhouse in Port Gibson that was built in 1895 by… the previous owners had remodeled in the 1980’s… as I am an amateur carpenter and handyman… after rebuilding the entryway… after reassembling the lock… now the inside doorknob spins without seeming to activate the latch and the outside knob won’t turn at all… thank you in advance for your assistance…   -Perplexed in Port Gibson.

Dear Perplexed:  Thank you for the three pages of colorful and insightful documentation (complete with photographs!) on your restoration efforts.  You’re walking a noble, if sometimes convoluted, path.  But I believe the solution to your problem is rather simple.  The spindle your doorknobs mount onto is not aligned correctly in the lock.  You will notice (Ed. See above) that your lock has two little buttons protruding from the faceplate.  One of these buttons prevents the exterior knob from turning, but in order for this to occur the way it was designed to, the knob spindle, specifically termed a swivel spindle, must also be in two pieces and aligned in the center of the knob hub inside the lock, which is also in two pieces.  So here is your easy fix:  Push in whichever button is out to free up the exterior knob.  Remove the knobs and position the swivel spindle so the two halves are centered exactly in the middle of the mortise lock (on most spindles you will find a stop that puts you in the correct spot).  Finally, reattach your doorknobs without moving the spindle out of place.  You’re welcome in advance.

Dear Xavier:  We are having a lakeside cottage built as a summer get away, and I found a beautiful antique lockset online that I just have to use for the front door.  My contractor says the “hand” of my door is wrong, whatever that means.  Can’t anything be done?  I simply must have my way!  -Pouting in Pittsford

Dear Pouting:  The answer is yes… or no… maybe.  It’s complicated.  First, you should respect the advice of your contractor and understand that he wants to do a good job for you.  His concerns about the lockset working correctly with the door you want him to install are valid.  The “hand” of your door refers to the way it swings into or away from your house.  The hand of a door is taken from the outside.  If the door opens into your home and swings to the left, it is called a regular bevel left hand door.   If the door swings in to the right, it is called a regular bevel right hand door.  For doors that open out and away from the house, the same rules apply, only they are called reverse bevel right or left hand doors.  Because your lock is like a passenger riding inside your door, it is also subject to these rules and can be said to have a hand.  The hand of a lock is determined by the bevel of the latch bolt.  The beveled side of the latch bolt needs to close into the strike plate mounted on the jamb in order for the lock to latch and shut properly.  Now, most interior door locks have a reversible latch bolt which means they can be used on any hand of door.  With exterior door locks, reversible latch bolts are not as common.  Have your contractor sit down with the lock and remove the screws that hold the case plate on.  It should be immediately apparent if the latch bolt is reversible or not.  If it is, he simply needs to remove it from the lock, flip it over, and reinstall it.  Problem solved.  And if it can’t be reversed after all, well, then you’ve just collected a great piece of architectural history!  Win, win!

Post all of your antique mortise lock comments, queries and conundrums to Xavier Blaine, Hardware Detective! c/o Historic Houseparts.  He will endeavor to elaborate on an explanation in a manner befitting a man who sets his watch by geologic time.

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