I designed this Gate Latch for strength and to be easily to printable, to be used for large and/or heavy gates with a D or Latch locking system.

Gate Hook:
I printed the hook with 5 perimeters with a 0.4mm nozzle to make the walls 2mm, and with 4 top and bottom layers at 0.22mm to make the top and bottom 1mm thick, with 15% infill.

Gate Bracket:
I printed the hook with 7 perimeters with a 0.4mm nozzle to make the walls 2.8mm, and with 6 top and bottom layers at 0.22mm to make the top and bottom 1.44mm thick, with an infill of 20 - This was to give the bracket strength to take the impacts of the gate being closes onto the bracket.

Gate Pin:
I printed the gate pin with the maximum number of wall making it solid, instead of doing a 100% infill, I heard it makes it stronger.

All parts were printed with a high temperature to increase layer adhesion.

Assembling:
The best way to assemble it is by assembling it on a flat surface and putting the head of the pin (large end) onto the work surface and then using a square of baking paper / grease proof paper to cover the other end of the pin which is protruding out, then with an iron gently press down onto the top of the pin to soften and melt the pin to create a "rivet" of sorts. - Or a bolt could be used.

Happy Printing :]