Review on Premium Replacement Keyed Patio Sliding Door Handle With Mortise Lock And Key Cylinder, Fits Doors 1.5 To 1.75 Inches Thick, Reversible Non-Handed Design, 3.94-Inch Screw Hole Spacing by Jay Hill

The mortise lock on our patio door (which we use a lot) broke, so we decided to replace the whole mechanism since the outer handle disintegrated when we took it off. Our old set had a key lock (which we never used) so we decided this was the closest thing. There were no instructions whatsoever, so you'll need to go on YouTube to find out how to take out the old lock and install a new one. This set came with 2 very short screws to hold the lock in place and we could not get them to grab and ended up losing the lock down inside the door. (Be sure to insert something through the lower screw hole to keep that from happening and to hold the stiffener in place). We got a new mortise lock from Home Depot which had sufficiently long screws. We ended up using our old interior handle since it was of much better quality, and the rod that trips the lock was already the correct length. The rod on the interior handle with this set was much too long and would have to have been carefully cut off to use with the key lock, and also the screw holes in the door were too small. The rod on the outer handle with the key had to be shortened, and that had to be done carefully to make sure it is the right length. After many hours and choice words, I finally got it to work. So out of this set, the only part we ended up using was the exterior handle with the key lock. We really didn't ever use our old key lock since that would only have been used as a last resort if we had locked ourselves out. Before you buy this, think carefully about it and be prepared for a rough time.