Summary

Prevents your child from turning on your oven and/or changing the temperature. Snaps right on to the oven handle if your oven looks like mine. Tested successfully on a 12 months old baby.

Instructions

First find out if this will fit your oven. It should look like the photos attached to this Thing. Also ensure that it never gets hot enough on the outside to melt the plastic you print with. PLA should probably not be used.

Open the .scad file in OpenSCAD.
Measure your oven and tweak the parameters at the top of the file.
From the Design menu, select "Compile and Render (CGAL)" and then "Export as STL".
Slice and print the STL with support material enabled.
Cut away the support material, which will be under the arch.
Open the oven a bit and insert the Thing under the center of the handle. It should snap into place without too much force -- don't use tools.
Slide it along the handle to cover the desired dial.

Oven shield for child safety