Tuesday, 18 August 2015

Types of Door Handles - Part 3

Mortice Knobs - The use of mortice knobs is becoming more popular with the more traditional type of doors. It is important that if mortice knobs are selected that the choice of locks and latches works with these. The following points are important.
The locks/latches are deep enough to avoid hitting your knuckles, At least 100m locks with 75mm back set. This is the distance between the door edge and the position of the knob.
The locks are sprung lightly enough that they are not too difficult to turn. These often need to be ordered as specials as most modern locks off the shelf are heavily sprung to work with lever handles.

Types of Mortice knob locks
I would often recommend the use of horizontal locks which put the turn or escutcheon at the side of the knob and not below it. In addition these types of locks can operate the latch when you turn the knob either clock wise or anti clockwise. This would never be required with any lever handle as it is obvious  the handle is always pressed down. With a knob however it is 50/50 on whether the person turns it clock wise or anti clockwise.
If you want to use horizontal locks designed to work with knobs then you have to consider the design of the door. If you have a flush door there is nothing about the design that will prevent you from positioning the handle where you want.

Mortice latch with 100mm back set

The image above shows  a mortice knob using a 100mm lock with a backset of 80mm. As this door is a modern flush style door the handle position is further in and looks aesthetically pleasing
    


The video shows a horizontal lock in use with a back set of 127mm. This puts the knob in line with the panels and shows the dual action function of this type of latch. This will operate the latch in the lock when the knob is turned either clockwise or anti clockwise. This dual function however will only work on an inspiring mortice knob



If however the door is a panelled design then some designs will not enable the knob to be set in 125 mm or even 75 mm which is the minimum distance as this looks aesthetically wrong. 

Mortice handle with 60mm back set
The image beside uses a standard latch with a 60mm back set. The knob is too close to the edge of the door and increases the chance of banging your knuckles when shutting the door
Ideally you need a door with a mid rail that is between 900mmm and 1M to its centre point.

This particular example in the images below show the centre point of the lock is 1M up and the backset of the knob at 127mm lines up with the edge of the panel and the turn and release is 57mm in from the edge.
Centre point of lock 1m upCentre point of internal door lock 1m up

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