I have a Schlage smart lock with a key pad and a keyed lock on the outside so the lock can be opened using the keypad or the key. I would like to disable the key function so it can only be opened with the key pad. I would’ve thought there was some kind of blank replacement for the key slot but I haven’t found anything. Any ideas?
If you really want to do this, a locksmith may be able to rekey the cylinder to an "impossible" key, or (probably better) disconnect the tailpiece that lets the cylinder operate the latch mechanism.
Doing that may or may not interfere with maintaining the lock in the future, and the details will depend on the cylinder and lockset, so I personally don't want to get into discussion of it as a DIY project.
An alternative can sometimes be to swap out the cylinder for a higher security one, or to install modifications to make it more secure. On the other hand, a high security cylinder in a Grade 3 lockset is a bit of a joke unless you are more concerned about tamper detection than prevention. You may be looking at the wrong part of the system.
As others have said, you probably want to consider how you will enter the building if the lock loses power or otherwise malfunctions.
Make it blank.
Buy a replacement cylinder for your lock.
Replacement so you can go back to keyed version.
Open it up and take a picture or more.
Take the first and last springs and the bolts out (and save for later)
Now it will maintain the appearance of a key and any key will go in but it will not unlock anything.
Certainly there are other probably better ways to do this, but this is one I know.
This is not your cylinder, it is just a example