Catproofing

Ever since we started letting the cats out, they have become real pests about going out and have figure out how to brute force the screen door. By putting their weight on the frame and clawing to the right, it is fairly easy to bypass the simple Andersen locking mechanism.
There has to be a better way.
Earlier, they broke the knob that latches to the screen and I found a replacement 3D model on Thingiverse. It has worked well, but proved to not be sufficiently cat-proof.

The problem is that the standard latch only prevents lateral movement. As soon as the cats put weight on the door and push it out, the latch disengages and slides open easily.
So my thought was what if the latch grabbed the screen door? I found this on Thingiverse, but it would require too many new holes in my door and frame.

So off to Tinkercad…with a slight detour to SketchUp. It took some searching, but I was able to find a 3D model of the handle in their 3Dwarehouse. Unfortunately, the model was in Sketchup format and I don’t own Sketchup. Luckily, their free web version will let you save in STL format, so I could subsequently tweak it in Tinkercad.

My plan was to add a plate to the handle so my latch had something to grab onto. That was pretty simple. When I printed the piece, the only surprise was that the back of the finger cutout was only hanging on by a hair and popped out. I may fix this at some point, but for now it is fine.
Next I needed to tweak the latch. Again, this was pretty simple in Tinkercad.

This worked pretty well once installed. The door was now rock solid when locked, but it was a little too tight and hard to open.

Another tweak shortened the latch portion and extended the grip.

I tried to extend the base (the round part) so that the latch better lined up with the door handle, but it wasn’t enough. But instead of remodelling and reprinting, I simply resorted to some old fashioned washers to offset the mechanism sufficiently.
Now the door is cat-proof and wife friendly…at least until the cats simply break through the screen.