This is part of another project I'm working on, but could be modified for other uses. I'd been tossing an idea around for a few years that required a flat belt buckle, but every buckle blank I found was curved. I finally ran across a buckle back hook and loop from Tandy Leather (http://www.tandyleatherfactory.com/en-usd/product/buckle-back-ring-hook-1-1-2-38-cm-to-1-3-4-44-cm-1803-00.aspx), but it wasn't quite what I was looking for either. Flipping through the 'DIY Gifts' group on here, I found the 'I Heart Bacon Buckle' by Mrballeng (https://www.instructables.com/id/I-Heart-Bacon-Buckle-From-Scratch/) which made me think about using a material that I had never contemplated before - copper pipe.
This one is pretty rough looking, because it will eventually be attached to something else, but the design could be changed to make a full copper buckle. which could easily be engraved, etched, polished, etc.
Step 1: Design
My design is similar to the buckle back sold by Tandy. Since mine will only be used as the working part of the buckle it's a simple design. I started by drawing a template. I just drew it out on a piece of paper. Modify as needed.
Step 2: Gather Materials
flat head screwdriver (or some other prying tool)
a saw to cut copper pipe (I used a metal cutting bandsaw, but a hacksaw, sawzall, or dremel could also be used)
copper pipe (see below for sizes)
wire coat hanger
The idea is to split the copper pipe and flatten it out to make a copper plate. I used 1/2" copper plumbing pipe. I determined that 1/2" would be large enough by wrapping my template around the pipe. The template didn't overlap itself, so as long as I can utilize the entire circumference of the pipe, I'll be OK.
My design is 1" wide, so I could also have calculated the circumference of the pipe using the following equation:
Diameter * pi = circumference
0.5" x 3.14 = 1.57"
Knowing that if I cut a slit in the pipe and flatten it out, it will be 1.57" wide, this size pipe will work for my application. If I only had a way to cut the pipe completely in half (i.e. - with a scroll saw), I would need a larger diameter pipe, as a 1/2" pipe halved would yield a piece that was only approx. 3/4" wide when flattened out.
A 1" diameter pipe would yield a wider piece.
1" x 3.14 = 3.14" circumference. Halve that 1" pipe and flatten it and you get a 1.57" wide plate.
Step 3: Cut and Flatten
If needed, mark the cut line. Lay a marker on the table and while holding the pipe flat on the surface, drag the tip of the marker the entire length of the pipe. This will give you a nice straight line down the pipe. Time to start cutting. I used a metal cutting bandsaw so I was able to slit one side of the pipe. You could also achieve this by clamping the pipe in a vise and using a hacksaw or dremel to cut just one side. If you're really good with a sawzall, you could also use that, but I don't think it would turn out all that good.
Once the pipe is split, use something to pry it open. Here's where the gloves come in to play. The edges of this pipe can be very sharp. Mix those sharp edges with the force needed to pry this open and you're bound to slice up your hands. BE SAFE!! I was surprised at how stout this copper pipe is, especially when working with such a short length.
Keep prying to get it open enough to hammer it flat. I used a variety of methods for this. The handle on my vise has a round nub on each end that was the perfect diameter to help spread this out. I just drove the pipe onto the handle which spread the opening wider. Once it was wide enough to fit over one of the jaws of the vise, I hammered it a little bit and then turned it a little. Hammered more and turned. Repeat until you end up with a flat plate.
Once it was flat, I cleaned it up a bit with a flap wheel in my drill.
Step 4: Cut to Shape
I cut my paper template and held it on the copper plate. I marked around it. For small intricate work, you could use some spray adhesive and attach the template to the plate and just cut through the template.
Step 5: Make a Belt Ring
I used a wire coat hanger for the belt ring. Just cut the straight section from the bottom of a hanger. I used some sandpaper to remove the yellow-ish coating from the hangar.
Belts come in all sizes. You can make this a one size ring, or you can make it to fit multiple width belts. I think the most common is about 1-1/2" wide. ***Keep in mind, if the ring is wider than your belt, the buckle will be able to move up and down a bit.
Mark out the width of your belt. This will be the section that attaches to the buckle end of your belt. I marked mine for 1-1/2", the sides for 3/8", and the each end for 1/2 the width (3/4"). Use the vise to hold the wire to achieve crisp bends. I found that using an adjustable (crescent) wrench works well as a "hand held" vise of sorts. My crescent wrench also has jaws that are ~ 3/8" wide, so it worked perfect to form the sides of the ring. Bend the last two legs into meet in the middle. A good way to make sure there is a minimal gap where the two ends meet is to make both bends so the ends overlap. Then cut through both ends at the same time. This will ensure that they are the perfect length to meet each other.
***You may have noticed that the ring I'm holding is rectangular, while the ring shown on the first page is trapezoidal. I'll talk about that in the next step.
Step 6: Finishing Up
Here's where pics get scarce. I got in a groove and forgot to snap pics as I went. I started with the flat plate cut to shape and bent it to what you see in the 2nd photo.
I started by clamping it in the vise with just the ring straps extending out the top. I bent them 90°. I put the belt ring in place. At this point, I still had the rectangular ring, but realized that since the ring was 1-1/2" wide, the buckle piece (1" wide) would slide on the ring. To prevent this, I bent the sides of the ring so they angled towards the buckle piece. I then bent the ends so they overlapped and cut them so they met in the middle. This gives a trapezoid shape that will keep the buckle centered.
Once the ring had been modified, I put it back in place on the buckle and bent the straps all the way over the ring. The copper tends to "fold" rather than "arc" around the ring, so I clamped the buckle in the vise, trapping the ring. I kept a bit of room between the ring and the top of the vise jaws and tightened it down. A few hits with a hammer helps bend the strap AROUND the ring, making a hinge of sorts. When you unclamp the buckle, the straps will likely spring back a little and won't be touching the buckle. We'll fix that in a bit.
Now for the hook. I left this part extra long so I could fold it back on itself to give a little extra strength. You'll have to judge how long you want the hook piece and fold as necessary. Hammer it flat.
Before you start bending the hook shape, you'll need to keep these two layers of copper together. I used regular Rosin core electrical solder because it's much thinner and takes less heat to melt, but plumbing solder would work too. While you've got the torch fired up, grab some pliers and squeeze the ring straps down and solder them as well. Once things cool off, you can start to form the hook.
I started by hammering the square corners of the hook so they were slightly rounded. I then used some pliers to bend the "hook". Once it was formed, I used a flat file to smooth things out a bit and then sanded the whole thing down.
At this point, you're basically finished. Install it on a belt and wear it.
Step 7: Options
As I mentioned at the beginning, this is part of another project I'm working on. I made a leather holster for my phone that I will be attaching to this buckle. I'll hopefully have an 'able on that in the next few weeks.
Something else that I may try is cutting another piece to use as a face for the buckle, solder them together and polish it to a mirror shine. Another thought is to use a PCB etching solution (for making printed circuit boards) to etch a design on the face of the buckle. Not sure how well that will work since it's typically only used on copper clad circuit boards...