This square buckle is sized to match the onscreen proportional similarity to the speartip buckle. If you resize one to scale up or down by a specific percentage, you can duplicate that for this square buckle and they will continue to look appropriate regardless of 1.5inch, 1.75 inch or 2 inch belt strap width. This stl is sized to match the image of Adam at a 1.5 inch belt width. This square buckle has room above and below the 1.5 strap Adam is wearing so this buckle will have the same gaps if printed at 100 percent and used on a 1.5 inch standard belt.
I created this as a center swing pin rather than a side pin. Because of this I have left the pin out of the print. Brass craft rod in 3 to 4mm (approximately 1/8 inch) would be correct for a stronger belt but the 3mm would be far easier to shape. Most pins are slightly flattened at one tip and folded around a second length of brass to get the approximate round shape to slip over the center bar. Keep the bend open enough to do this. I fold mine over the other wire (extra length of the same wire you made the pin from) until the fold is parallel to the longer section (of itself). Slip this onto the center bar fully and check the length of the pin (must land on the flat face of the buckle correctly). When this length is correct, you can close the fold a little further and it will stay on the buckle. Because this is a metal pin on a plastic buckle, attempt to bend only the very end of the folded section to avoid clamping it down tight on the center bar. I will add pictures of all of the above as I finish my buckle.
Here is the rendered image file:
and the print file is attached here at the bottom of this post.
One last caution on this print: let it cool completely before removing it from the print bed. Flat objects warp easily while cooling so it is best to allow it to cool while on the bed. Which of course reminds me that I print this face
DOWN with no brim and no first layer expansion and no skirt. I did use tree supports, on print bed only, to support the bar. Printing face down ensures an entirely planar flat face that can be polished beautifully. Do not use raft either. My settings were .12 layer height, .2 line width on first layer, gyroid internal fill at 50% for strength.