What is a stub spindle?
Stub spindles are used in upvc door handles to restrict the movement of the lever and convert the handle to a pull handle. Not all door handles can use this spindle but if you check the details of the upvc door handles it will tell you either way.
I have a 7mm door handle spindle lock but the door handles need 8mm spindles?
In that case keep the 7mm spindle and push the 8mm sleeves into the handle levers.
Do all door handles have 8mm spindles?
Not all doors have 8mm but it tends to be the modern day size. You will get 7mm on some upvc doors and interior doors.
I have two half spindles in my door handles?
This is known as a split inline spindle and is found in some upvc door handles. If you are replacing your door handles then you will need to re-install these into the new handles to ensure the lock still works correctly. Split spindles mean the handles each side of the door work independently of each other so the door can remain locked from the outside.
My door handle spindle has a groove in it?
These are found on some interior door handle and knob sets and basically allows a grub screw to tighten down and into the spindle to stop any lateral movement. This provides more strength to the handle remaining on the door over time and takes the emphasis away from the short self-tapping screws just holding the handle to the interior door.