Can I use a thumbturn cylinder lock to replace my existing double ended key cylinder?

Yes that can be done, just measure the sizes correctly from the screw hole to the end each way as shown in the details of each thumbturn. We would always suggest keeping these thumbturn locks away from an exterior door where there may be access from a letterbox (special tools are used by burglars to reach inside) or where glass is present in the door (glass can be broken).

Can I still operate with a key from the outside when the thumbturn has been used on the inside?

Yes that is the case and is useful particularly when you need access to the house, such as a carer, as there is no danger of the keys being left in the lock from the inside.

Is the Yale Superior thumbturn a secure lock?

No one can say their lock is secure but you need to look out for the features and tests and make sure you are happy with the design of the lock and what it offers. The Yale Superior meets a lot of standards and comes with the special anti-snap resistance bar as well as having the 1 star TS007 standard for anti-bump. It is also Kitemarked.

How do I get my old thumbturn euro cylinder off the door?

You release the screw from the side of the door and then turn the thumbturn end, pulling at the same time, until the barrel slides out of the door. We have a simple removal guide here which shows a cylinder with a key but the same is correct for a thumbturn ended cylinder only you pull the cylinder out from the inside.