Hacks: Stop Using Incorrect Mortise Lock Spindles Please!

Two days and two people locked inside because somebody halfassed the replacement of the knob spindle on a mortise lock.

Yesterday I had a customer who wanted to show a condo but people kept getting stuck inside the unit after they shut the door. This wasn’t a strong selling point. To get out somebody had to crawl out the window and unlock the door from the outside with a key. Fortunately they were on the ground floor! It was all due to somebody replacing the original spindle with a straight spindle instead of a swivel spindle.

This is a straight shaft spindle with a wad of tape around it to make it work in a lock with a larger diameter for the hub. It was responsible for locking a poor lady and her dog inside for a long time.

Today I encountered the exact same scenario on Capitol Hill! A lady got locked inside her unit. When I pulled the lock apart I discovered somebody used a straight spindle wrapped with about half a roll of electrical tape to make up for the spindle being the wrong diameter. It works for awhile but a few years down the road there’s a real headscratcher to contend with that could be avoided with an inexpensive part.

Entry function mortise locks typically have buttons on the side to facilitate locking the knob on the outside. Due to fire codes (and plain common sense) the inside knob should always be unlocked, and to make this work you have to allow the inside knob to rotate independently of the outside knob, meaning there must be a swivel in the middle of the knob spindle.

If somebody replaces that spindle or if they adjust the placement of the spindle so the swivel is no longer in the middle of the lock, the knobs can no longer rotate independently. They are connected on a straight shaft. If somebody then pushes the lock button on the side of the door and shuts it they will be locked inside.

Here are some Ilco spindles. 760-07 and 12 are swivel spindles. 760-11 are split spindles.

Ilco manufactures a number of different replacement spindles for mortise locks including swivel spindles that come with little expansion things that slide on over the spindle which negates the need for toothpicks or electrical tape or dental floss or whatever else is revealed to the handyman’s mind in his “a-ha moment” of realization that he needs a larger diameter spindle and maybe wrapping random household objects around it will fix it.

When replacing parts on locks it is important that the function of the lock is considered and possible failures anticipated. A lock malfunction during a fire or gas leak for example could result in unnecessary injury or death. Electrical tape and wood glue aren’t durable enough for use in can’t-fail applications like the only door to a rental unit.

Other problems encountered with the lady’s door: an auxiliary deadbolt was installed upside down with the boltlatch surface mounted instead of mortised in. There was no strike plate installed, just a hole in the wall.

When you don’t mortise the boltlatch in it will scrape on the doorframe and when the screws on the strike loosen it might prevent the door from opening at all. The silly thing is that this deadbolt came with a drive-in part that is used when mortising is not desired. There’s no excuse!
Strike plates distribute the force of somebody kicking the door over a wider amount of wood, thus making it harder to kick the door in. This deadbolt came with a very good strike plate, the maintenance guy just didn’t bother with installing it.

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Bjørn Madsen

I am the Seattle locksmith you've been looking for. High Quality work at a reasonable price delivered in a timely fashion.