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Cleaning and Repairing an Antique Mortise Door Lock

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If you have an older house with knobs that slip, latches that are stuck inside the door, or other minor problems, then you should follow these instructions to remove the lock, dis-assemble it, clean and perform minor repairs.
 
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Step 1: Meet the mortise lock and door knobs.

This mortise lock set is installed in a 1930 colonial in the Boston area.

Notice the set screw on the base of the knob on the right. This screw should hold the knob securely to the spindle when you turn the knob.

Step 2: What's a spindle?

Picture of What's a spindle?
The spindle is threaded to hold the knobs on, but has flats to operate the lock mechanism and to allow the set screws in the knob to hold the knob securely to the spindle.

If the set screws become lose they will allow the knob to turn without actuating the lock mechanism. If your knob is "slipping" try tightening this screw.

Prolonged use with a lose set screw can damage the spindle. If tightening the set screw does not help, you should be able to buy a new spindle at your local hardware store (not the chain with the 16 year old clerk, find the one with the proprietor who is approximately as old as your home).

Step 3: Loosen the set screw.

Picture of Loosen the set screw.
To remove a knob, find the set screw on the base and loosen it just enough that the handle turns freely on the spindle.

Step 4: Remove a knob from the spindle.

Picture of Remove a knob from the spindle.
Unscrew that knob from the spindle. Make sure not to drop it!

Step 5: Remove the spindle from the door.

Picture of Remove the spindle from the door.
To remove the spindle, pull on the other knob with the spindle attached.

If you need to replace the spindle loosen the set screw on this knob, and unscrew the spindle from the knob to remove it.

Reverse your steps from this point to install the new spindle.

Step 6: Free the lock face from any paint.

Picture of Free the lock face from any paint.
Before you remove the lock mechanism from the door, you may want to score the gap around the lock front with a razor to free any paint that may be attached to the metal.

If there is paint on the lock face, then when you remove the mechanism the paint may stick to the lock face and peal off the wood of the door.
AndrewCampbell12 months ago
Antiques are fragile and need special care and storage methods in order to ensure they are in perfect working condition and can continue to be used for a very long time ahead. It is better to seek professional advise when it comes to cleaning or repairing them. Else, you might just sacrifice your priceless gems to become useless junk.
KI0DN1 year ago
Excellent presentation. Thank you for showing me something else I may tinker with.
This is really neat. I love this kind of stuff, thank you for sharing!
parkwood601 year ago
It appears the code for the recaptcha is broke, as it is not appearing in the reply box, only in the write new comment box...

You can use WD-40, or 3 in 1 oil, or anything you'd like in a mortise lock. The tolerances inside are so huge dust and dirt won't affect it the way they would a modern pin tumbler cylinder. Lots of them have gobs of grease in them from the factory.
parkwood601 year ago
I am having a hard time replying to the comments, but I have fixed just about every kind of these locks and I'm willing to help you do the same.
browne2 years ago
I have a sargent mortis lock 5131 and the leaf spring broke that holds the latch out. Is there somewhere I can find another leaf spring?
Thanks
jmichaelkel2 years ago
I have this same lockset in a door to a rental unti I am re-habbing. Where can I find a replacement threaded spindle (split halves), interior knob, and escutheon for the knob?
in nova scotia, as recently as a decade ago, rods, crystal and plain brass knobs, even replacement locksets, were available in the nearby hardware store(national chain). there's a kind of lockset that has a push spring, a decent effort can be made by putting the spring from a click pen into them.
chriswren (author)  jmichaelkel2 years ago
Fortunately I haven't had to replace a knob, but I have seen them in nearby antique stores. If you're in Boston there's one on Charles Street, downtown: http://goo.gl/WeqKs

The threaded spindles I've picked up at my local hardware store. If yours doesn't have them try to find one in a neighborhood where there are a lot of houses of the correct age.
Thank you for the response. Unfortunately, I live in northern California and there do not seem to be mnay sources for this old hardware. The old knob looked as if it had been cross threaded on the old spindle over the years and there is a lot of slop in the operation. The cam inside the lockset looks good. The spindle is split in two halves and is threaded There is a small downturn on one end of one half which looks to be some sort of catch at the cam side. The spindle is pretty badly bent which is why I am trying to find a new one. The replacement spindle and knobs which you can get commercially at places like Home Depot will not work. Also, the deadbolt I got to be functional but the small knob which operates it is also badly bent and affects its operation as theknob is turned. It looks like pot metal and I am afraid if I try to straighten it, it will snap. I plan to check a few places out today that I heard of - an antique store and a locksmith who has been around for awhile. If I luck out, it seems I have no recourse but to pull it out and plug or fill the door, then pep it for a current lockset and deadbolt. This would be unfortunate as the door I preserved and the lockset is pretty cool with the ornamentation of the handle and deadbolt.
Yokena2 years ago
I'm so glad I found this site as I just might be able to solve my door lock problem.

I have locks on front & back door marked as "E-Z Mortise", made in Taiwan. They seem to be old and are made of mostly cast iron and brass. It may be that they are a copy of the old Sargent lock as they look very similar.

What I need is the brass cam, as shown in the third picture. The cam tabs are not the same, one being wider. The wider one is worn down to the point it no longer functions.

It I can't find the cam, I suppose I could have a machine shop build up the cam but it would probably cost more than a whole new lock!

Any advice would be appreciated.
DoorLock-1.jpgDoorLock-2.jpgDoorLock-3.jpg
vcortlandt3 years ago
Where can I buy one of those springs?

i also need springs--did you find them?--scott
Believe it or not, those metal reinforcing strips that are in most wiper blades will work well sometimes. BTW, it helps to lay the lock chassis down cover-side-up on a table before you take it apart. Take pix of it once you open it so you remember which way everything goes together.

If it's a Sargent Easy-Spring, the hairpin spring attached to the chassis bottom up near the cylinder opening usually goes. You can usually make a spring for it "in place" by using the chassis as a bending jig, but it needs very narrow stock. You can narrow the stock by grinding carefully...just don't overheat it and ruin the temper.

Another thing that goes (in an outside door lock) is the spring in the cam disc that fits in the inside cylinder opening. Not all locks have these, but the ones that do rely on the spring to keep the cam in a neutral position. Otherwise, it can flip down and jam the bolt...usually in the locked position. it's difficult to replace that hairpin spring, so I usually replace the whole disc (found at your local 'smith).

If the lock has a key cylinder, there will be either one or two setscrews holding it in place (sometimes hidden under the edgeplate, or scalp as it's called). If there is only one, it has a LEFT HAND THREAD.

WARNING: Some newer mortise locks (like General and Schlage) have VERY strong springs in them and should only be taken apart with a special fixture that controls the release of the spring tension...or you may end up in the emergency room.
chriswren (author)  vcortlandt3 years ago
I bought mine from mcmaster:
http://www.mcmaster.com/#9654k116/=cipe6t

I measured the dimensions of the old springs and tested some under load to calculate the bias and spring constant. Then I used their website to search for close matches.

Thank you............
n_b_c2 years ago
this looks like a good site, so now that i have the answer to my mortise lock question, i,ll add my own tip:have any of you tried this?
we had a pair of big old double doors, with very worn/dropped non ball-bearing hinges. as they were 5 inches by 5 inches, replacements were not easily obtainable without waiting. we swapped the higes from top right to bottom left, and vice-versa. this not only brings the less used inactive door hinges over to the active [more wearing side], but the wear takes place on different surfaces, depending wheather the hinge is installed as left-hand or right-hand. if you draw it out you can see how the wearing points change left to right. it got us out of a sticky situation!--nbc
joldfield2 years ago
I am repairing an older (1905 ish) mortise door lock. I cannot find a way to remove the knobs, there is no set screw, but what appears to be a metal dowel through the knob. Is there any way to remove the knobs without removing the metal dowel as I am not sure about the durability of the lock in general and don't want to damage it?
any experience with a mortise lock that has a set of buttons at the top that allow you to 'lock' the latch portion? that's what i have on my front entry door & now that i have it cleaned up i believe it's missing a part to help keep the spindle housing pieces in place (i have 1 piece with this task at the moment). the coil spring for the latch is actually on a post inside the latch itself, so my guess is i'm either missing a solid metal piece or possibly a leaf spring. my theory that someone LONG ago opened the lock box is somewhat confirmed by the fact that i believe the piece that holds the buttons in place was upside down when i took the lock apart. all the rest of the mortise locks in my house for the inside & side entry doors don't have this feature so i can't easily compare :-( she's a PENN Pat. Nov. 5 1912
lock_front door_clean2.JPG
chriswren (author)  n_toxic_ated2 years ago
Sorry , I don't have any locks like that, but thanks for posting the photo. It's a cool looking lock.

Sounds like dll932 has your back though. good luck!
I saw your note on finding a second lock. Did it have a different latch? The buttons on my lock are just as yours are, but the latch is solid with no spring. The pin that slides in the open space in the right end of your latch is instead linked to the latch.

There is a small leaf spring at the top of the enclosure that pivots the cast half circle and the latch to which it is linked back into the closed position. I can see hardware stores stocking replacement latches and springs when the correctly-sized little leaf springs were no longer available.

I'm not by the computer with the pictures right now, I'll try to post a clear picture later.
here's the 2nd lock i picked up (not yet cleaned). upon closer inspection i see 2 long, flat pieces of metal in the top right corner area, likely a broken leaf spring from somewhere, so who knows if anything else is broken or missing.

i'm also attaching a pic of one of my interior locks (not cleaned either, but clearly didn't get exposed to the weather!) with no coil spring either.
another button mortise lock.JPGinterior door mortise lock.JPG

Glad I live in a dry climate! just spider webs and accumulated dust to clean.

You can see the leaf spring across the top of the enclosure.  It goes under the two-button locking mechanism, which is not sprung (back to original question).

Except for the solid vs slotted latch shaft your front lock and mine look very similar.
P1010800.JPGP1010803.JPG
dll932 Utemike2 years ago
Looks like your leaf spring is upside down-it should be that lever against the case.
i'm not at home right now so i don't have the lock with me & i don't have pics on my laptop since i haven't cleaned it (yet?) so i'll take a look in a day or so.
You are missing a leaf spring that helps return the latch to the closed position; it runs parallel to the case bottom and pushes the "question mark" shaped piece toward the lock face. It looks like you are missing a hairpin-shaped leaf spring the helps retain the button position. If you want, you can disable the latch portion of the lock by removing the buttons and links. Penn is a very old name in locks, by the way.
chriswren (author)  n_toxic_ated3 years ago
we have that same kind of latch on our front door, but I haven't tried to open it up yet. Sorry.
all's good! i found another mortise lock with buttons at a nearby antique store & after comparing them i realize i'm not missing anything, except perhaps the skeleton key that fits into my front entry door lock (the key i do have fits/works better in the mortise locks inside my house). good luck when you finally take yours apart! (i took one of my inside mortise locks apart afterwards - a mere 7 or 8 removable parts vs almost 20 in my front entry lock!!)
drobinson152 years ago
Any idea where one be able to find a mortise with a 3" setback?

It is labeled as D.M. & Co. from New Haven.
chriswren (author)  drobinson152 years ago
No idea, sorry. I actually misplaced one of mine (packed it up in a bag with some of my tools and set it aside when I couldn't finish the project one day). I was terrified I was going to have to try to replace it. Luckily I found it one day (months later) hanging on a hook in the closet. Whew!
aeray4 years ago
Excellent 'ible! I've restored quite a few of these locksets myself (and even mortised replacement doors to accept original hardware. A good tip that you might add: to remove paint from old hardware easily, put the hardware in a crockpot, cover with water, add a dollop of dish soap ("washing-up liquid" in the U.K. I believe) set the crockpot to low and leave it overnight. Thumbs up!
chriswren (author)  aeray4 years ago
That's an awesome tip! I do a similar thing for tough pans (boil dish soap solution in them to loosen stuff up) but it hadn't occurred to me to try it for paint). The lock on the bathroom door is particularly bad, I'll post back and let you know how it goes.
Paint stripper will work if nothing else will. Make sure there is no paint in the openings where the bolt and latch come out and on those parts themselves. If there is rust, at least take a wire brush to it and blow the dust out.
dll9323 years ago
WARNING! If it's a lock for an OUTER door, the spindle will be in 2 pieces. When you push the button on the lock face the OUTER knob is supposed to lock. If you screw the spindle halves together tightly (rather than leaving 1/2 turn of slop or more) BOTH sides of the door will be locked! Also, the split in the spindle is supposed to be in the vertical center of the lock-pay attention when installing and TRY THE LOCK WITH THE DOOR OPEN.

The usual reason mortise locks stop working is broken springs-one would do well to replace them all, if possible. A good way to clean out the lock body is with brake cleaner spray, followed by wiping with a paper towel. One of the FEW things graphite is good for is lubing the inside of a mortise lock body-if it has a cylinder for a key, lube with WD40 (or similar light spray oil) ONLY-no 3-in-1, no grease, no silicone spray.

Frequently the bolt will be bent from attempts to close the door with it extended. Being brass, they can be CAREFULLY straightened.

Painted hardware can be cleaned with paint remover and/or with a Dremel and rotating brush. The brass can polish up like new, but will have to be varnished or waxed after. NOTE: Some finished were purposely antiqued and won't like that way after polishing!
rgrimm1 dll9322 years ago
Sorry, but NEVER use WD-40 in a lock. It is a penetrant, but will dry out and gum up rather quickly, attracting abrasive dust.
Use dry graphite only, use a Q-tip or puff applicator to apply.

NEVER use varnish if you can avoid it. It does not hold up as well as CLEAR LACQUER IMNSHO.

Large towns' locksmiths will (or should) have the correct key blanks to make up a proper set for the door(s). They will need to be cut to fit correctly! Many skeleton keys will NOT work, especially for entrance doors. Even the sellers of mortise locksets say that skeleton keys will fit MAYBE 30% of doors...and that does not mean they will work, just that they will fit.

One more thing: interior lock springs were of three types; flat springs, compression springs (often used on the strikes), and tension springs (used on the bolts, etc.). You CAN find close approximations at some GOOD hardware stores, auto supply stores, and GOOD locksmiths.
You will likely NOT find flat springs at most places. Locksmiths are your best bet, especially the older shops.

And why do springs fail? Because the lock dried out the lube or wore it away, and folks force the lock to work when it should be EASY...this is why other lock parts get broken as well.

Hope this helps.
dll932 rgrimm12 years ago
Sorry to contradict. I have been a locksmith for more than 30 years. Much of that experience was rebuilding/repairing older residential mortise lock, some older than 100 years.

I have used WD40 for all of that time with great success in commercial, residential and auto locks, Example: I owned a car for 17 years. In that time I lubed the locks every 3 months with WD40 and they never froze or failed. Yes, it's a penetrant-with lubricating qualities. PBlaster, on the other hand has no lubing effect, and will cause locks to work HARDER immediately.

Graphite use hails from the time when locks only had large sliding parts with lots of tolerance. It still works fine with mortise lock bodies, but not in pin tumbler cylinders. I have seen cylinders so full of graphite they didn't move. WD40, on the other hand, will dissolve old oil and I have seen it immediately loosen up recalcitrant locks. I recommend it because it's easy to find and hard to overuse (it should not be used with most plastics-they may melt).

Varnish is OK as long as it's polyurethane-some lock makers use it as a finish.

"Skeleton keys" come in three patterns, one of which will open nearly all INTERIOR locks. EXTERIOR locks work on BIT keys, which must be cut by a locksmith (they have more complicated combinations since they contain more lever tumblers).

The majority of spring breakage I have seen was the result of rust or loss of temper of the steel.
rgrimm12 years ago
Caveat #1)
Use extreme care when removing the lockset from the door! It is likely cast iron or stamped steel. If cast iron, it will be brittle and can break easily if stressed. Often, the front brass face of the lockset is dependent on the case to hold it in place, and if the case is broken, you need to repair it.
A GOOD welder can BRAZE the thin cast iron section together again....do NOT use solder, it won't hold. And forget epoxy, it's a joke in this situation.

2) To remove the lockset, ALWAYS cut the paint away from the lockset using a sharp snap-blade knife or similar with a thin blade. This will cut the paint 'glue' holding the lock immobile...keep cutting until the paint is gone/cut free.
I then stick a hard dowel or similar in the knob hole, and use that to gradually work the lockset out.

3) Take a picture of the lockset with it out of the door.
THEN take a picture of it with the case open, but without removing any internal parts. This will give you a reference when re-assembling it later.

4) And this is important: Sometimes, the ORIGINAL installer of the lock will place a coin behind the lockset, with the date of the coin being the same year as the lock was installed. I find these every now and then....some dating back to the mid-1800's.
Save the coin. Re-install it behind the lockset when doing the install, and ADD a penny from that year you are working on the lock.
I sometimes add a short note on when I repaired the lock, what I did, and the name of the homeowner. And every now and then the household's kids get involved, and I have them sign the lock as a time-vault....they think it's cool, and it is.
Use acid-free paper.
Exiumind3 years ago
Hi, do you think its possible to make a little enclosure just for that thing you are pulling on the photo and the spring?

I want a simple lock to go with my electric strike, plus the actual door complete lock..