sliding door lock

This appears to be a very old style patio door handle set. We unfortunately don't sell anything like it, so you may want to consider a surface-mount set like our 82-005 to use as a substitute. These are nice because they have their own self-contained mortise, allowing them to install on a ton of different style patio doors. The catch is that you will very likely have to drill new holes in the door to install it. Look it over and see if you think this would be a reasonable solution.