I chose a stainless steel door hit, so I changed the anchor to stainless steel. Particularly for doorsteps it is assumed that it will be used for a long time, so the metals are unified with stainless steel as much as possible. The thing is firm and satisfactory.
I thought to put a seat on the veranda for strong wind protection + rain exclusion. When needed, I was hooked for a moment, I could drive six centimeters into concrete with my eyes looking to withstand the wind and rain, and I kept the unbroken strength once driven. Electric (not charging) drill and a bit for concrete were necessary, separately devised the hook metal fittings, and stopped it with bolts from the monotaro.