Planning to build a gate for a fence with horizontal 45x45 slats. Posts are pressure-treated 70x70. I have read some posts and it seems common to use an "N" frame. Should I use 45X70 for the frame in that case? As in the picture below. Or make a box frame, like in the second picture? I want to attach the hinges on the other side of the fence compared to the first picture.
Your first picture is correct, it must look like that and the naren should be as coarse as possible and firmly attached to both the top and bottom as well as all the ribs, but you should know that it is wood so it will probably sag on the lock side eventually anyway. Very long and sturdy hinges that attach to the rails at the top and bottom; a tip is to screw the gate with a little bit of lift on the lock side before you attach the hinges. There is always a risk that the bolts (carriage bolts) will give in the wood, and then the gate will sag and not close properly.
Question. The hinges should be on the opposite side compared to the picture. How do you attach them? The diagonal brace is in the way. Want to avoid building a heavy frame.
In order to prevent the gate from sagging, you need to have a beam at the top and bottom where the stile can rest between, and then you can attach the hinges to them. If you want a slightly sleeker gate, a metal frame is probably necessary to prevent sagging. Here you can see different ways that gates are constructed; some have descriptions at www.google.com/search?q=bygga+grind&tbm=isch&tbo=u&source=univ&sa=X&ved=2ahUKEwj76sWUldzfAhVowYsKHZoaCRMQsAR6BAgDEAE&biw=1536&bih=754#imgrc=-Yo8KpEGAWpUzM:
Ok thanks. I have to build a frame with diagonal braces then. Must have vertical studs to attach the slats to.
Make sure it is strong in the corners, that's where something will happen. There are so-called hörnjärn in various sizes and it's recommended to use carriage bolts and very small drill holes for these, so you have to thread them in. If the holes are too large, they might shift a bit in the hole, resulting in misalignment. Good luck 