Print PDF
Favorite
Email
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.
Remove these ads by
Signing UpStep 1Meet 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.
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.
| « Previous Step | Download PDFView All Steps | Next Step » |
Thanks
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.
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.
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.
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.
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
Sounds like dll932 has your back though. good luck!
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.
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.
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.
It is labeled as D.M. & Co. from New Haven.
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!
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.
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.
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.
I want a simple lock to go with my electric strike, plus the actual door complete lock..