Add to this size a sufficient length for spindle to attach your knob or lever.
Front door split spindle.
In photo 24 the door is 1 3 4 plus about of trim.
Era upvc split spindle pack door handle and door lock for key only entry by era 54 72mm era 4 2 out of 5 stars 3.
Split spindle relates the actual spindle inside the handles having a split in the middle.
Split spindles if your multi point locking door has a split spindle it means that when you go outside and close the door you will need a key to get back in.
Changing from single to split spindle operation.
Try to measure the overall thickness of the door and trim together at the point the spindle passes through the lock.
The overall dimension is 2 1 2.
It is in fact the key that turns the latch bolt.
Door spindles connect the doorknobs on each side of a door.
Dual spindle refers to there being two separate spindles usually used in lever pad door handles which are offset different heights.
The spindle passes through a square port inside the lock mechanism and operates the strike when a knob is turned.
This is because if you push down the outside handle it will not operate the latch bolt in the door.