Do not let it slam.

Sometimes a service call is simply just straightening out a bent bolt in  the mortise lock.  99% of apartment doors in NYC are equipped with a mortise lock as the main lock on the door.  This lock is two locks in one.  It serves as a latch lock and also as a deadbolt.  On the lock body there is a button that you can either flip or push in to activate the latch lock, and you always have to use the key to lock the bolt lock. The thing is that when the mortise lock is activated with the latch lock, it automatically locks the door when you close the door behind you.  So some people like to through the bolt out in order to keep the door open if they are stepping out for a moment.  What they don't realize is when the door closes with the bolt sticking out and it hits the frame it gets bent a small amount and over a period of time it could bend enough where it will stop flowing in and out and then your mortise lock is deemed useless.  So I went on a service call to one of our previous customers. Her apartment door mortise lock would not lock with either the key or the thumb turn from the inside.  I automatically knew that the bolt was bent.  So I informed the client and told her that I will try to fix the bolt because replacing the entire mortise lock would be in the hundreds.  When I took the lock apart right away it was apparent that the bolt was bent.  I took out the bolt, straightened it out and installed it back into the mortise lock. I went back to the apartment and reinstalled the lock.  So the next time you want to step out of the apartment and you want to keep the lock open just flip the button to the open position and that would be enough. In Forest Hills Queens there are many buildings that are over sixty years old, these buildings have the old Lockwood mortise locks.  The Lockwood mortise lock is one of the best.  It is very durable and very well made.  Sometimes I end up replacing them with the more modern type of lock by Marks.