This round finger flush knob is for cabinet and doors that can be opened/closed with your finger.
You can install it in panels greater than 13mm by drilling out a 1-½" diameter hole 12 mm deep. I was able to do that in a scrap 2 x 4. By drilling until the drill just starts to poke through the wood, it will locate the center. You can then use the drawing as a template to locate the hole center on the back of the frame and mark the 3 mm clearance holes for the 3 mm screws.
For any thickness wood frame you can force the 35 mm press fit cylinder onto the knob and press-fit the assembly into the 1-½" hole. Guaranteed with my reputation, it will not come out, if you use the 38.1 mm outside diameter ring. Other rings are also available that are a bit looser in the hole.
There is a small circular indentation on the front that shows where to push and where the center of gravity that closes the flap is located. Play with the axis to see how you want it to open and close.
The author marked this model as their own original creation.