We're in the process of remodeling our 1940s house. All the existing doors have mortise-style locks, antiques knobs and back plates that are original to the house. However, all of the keys are missing. I would like to replace the locking mechanism but keep the antique back plates and knobs – they look great. Is there a way to keep using these old knobs and back plates but add new locks? Thanks for your help!
Many companies and websites, like House of Antique Hardware, have been created to address this very issue - though most use reproductions of antiques, rather than original locks, due to the challenges of merging new mechanisms with older hardware.
To that end, it might serve you better to replace the lock in its entirety by purchasing one antique in design from a site like this one. Adding new parts to an old lock might not work, or might not work well. An experienced locksmith can assess the parts you want to keep and provide expert advice on whether this project is feasible. Good luck!