I needed to reinforce 1.5 in (38mm) lumber under the dinette seats in my travel trailer after the staples securing the cross members that supported the plywood started to come loose. The 5mm counter sunk holes should accommodate most appropriately sized wood screws.
I printed it in ASA with a 50% infill. Time will tell how well it holds up.
I am no pro and I realized after designing it, that if I had oriented the item differently in fusion, it probably would have defaulted to the correct orientation for support free printing. The one of the photos (largest surface down) is how I recommend printing it.
The author marked this model as their own original creation.