Disclaimer: There's no one way to do leather. Example, I fold my leather over a key ring...I see lots of people who tie it in a knot at the end.
I put a key chain ring tied to a post on my deck. A piece of cord off the back of a table chair that’s steady.
For diamond braid I take 2 strands of leather. I figure how long I want the choker & times it by 4. As I lose about 1.5 to 2 times the length to braiding & the ending knots. The rest of the extra leather is so the choker will size up big enough to slide over the head, fist, foot, whatever. Example: I want 14″ of braid as the piece is for a 7″ wrist. Therefore, I will get 28″ to account for the braiding loss & terminal knots. Then times that by 2 again as I will fold over the strands to go from 2 strands to 4 on my key ring. That means, total length of the two strands is 56″.
When that’s ready, I get a bit of saddle soap, conditioner or whatever to make the strands stick a bit better & smear it over the backs of the leather. Then rub the excess off. This part really helps with the braiding, but if you’re using really wide pieces or suede surfaces, etc it’s not necessary.
The diamond braid of 4 strands
I start with folding my two strands in half over the key ring. This stems from when I used to do a lot of key rings for holding my braids to my carabiner. Later we are going to cut the strands off this key ring, some people find it easier to start the diamond braid by cutting their two strands in half right away & securing all 4 strands together with a terminal knot. Skip the next step (#2) if you have feel like it or have too issues learning that method.
I cross the middle two strands, one over the other to start. When examining the pair in the middle, you will notice one crosses the other on top. I take the strand next to this and cross the top strand going back the other direction, but under the other strand of the middle pair. Now I take the only strand I haven’t worked with and cross that over the 3rd strand, but under the strand next to it. That’s one pass.
An alternative method for starting your braid. Here’s a video for doing the diamond braid from a knot instead of over the key ring: [Link]. I still recommend sticking the knot on a key ring for easy of use but it’s not critical.
At this point, we have completed a single pass on the braid. We are going to tighten the braid now. Grab two strands in each hand and pull them outward, then downward again firmly. This makes for a nice braid. If you pull with the same force each time, the diamond braid will be evenly shaped and the pattern will line up in a very pretty manner. A note: Some people only pull outwards or downwards to even the braid. I do both, it’s based on what you are looking to get from your leather. One extra consideration, is that only pulling outward uses more leather. While pulling each pass of the braid downward uses the least leather. With both methods out & downward using somewhere in between the two.
From here, we repeat the process. To start the next pass, you take the strand that looks to be the closest to the key ring and do an over 1, under 1 pattern for each. Tightening every fourth strand at least. When I started I tightened every strand. These days I tighten every other strand.
Note: There's nothing to say that you couldn't do an eight strand or more here. I've pulled off a few 8's with pre-cut 3mm wide superior calf lace from tandy's leather without a core. The softer or wider the leather, the more of a need for a core.
The turkshead terminal knots
Tie a turkshead terminal knot on the end. I learned the turkshead terminal knot to finish the diamond braid from this [link]. I actually recommend learning it from the paracord guild page, as they have a great video too! [Link]
Then tie a loop around the top of the braid below the key ring or the knot you put at the top. To hold the top together when we cut it off the braid from the ring or temporary knot.
Tie a second turkshead terminal knot at the top end. The braiding is now complete & will not fall apart on you. I use a fid to tighten both of my terminal knots at this point and smear a bit of saddle soap on them, as I traditionally don’t use the saddle soap on knots till they are done.
The Spanish Ring knots to hold the choker
I form a loop with the braided length and place the terminal knots near each other. In between them, I start my spanish ring knot to hold the necklace/bracelet/anklet together.
I learned my spanish ring knots here: [Link] & via a youtube video. One tip on the Spanish ring knot, at the beginning it’s often hard to tell what’s happening on the back, via the diagrams. You are moving the two strands you laid already over each other & then threading the “working” end through them to secure the initial pass.
Bonus; you can add colors to the Spanish ring knots with other cords if you do a 3rd pass very easily. [Link]
I tie two Spanish ring knots as it’s most effective for me. I have seen a single Spanish ring knot of 3 passes holding the choker & little end keepers holding the ends flush to the braid as the size of the choker is adjusted. I have also seen 3 ring knots with the middle keeping the front of the braid on the neck neat & a little pendant hanging off it.