Hi all - Apologies for asking such a dense question. But I’m completely self-taught and have a lot of dumb questions while sitting here in my cave. 
I want to try making some curb chain. And while I see a number of great postings in this forum about the technique, I’ve not yet found much guidance on good dimensions for the actual links. On a side note, I have a great book on loop-in-loop chain by Jean Reist Stark. I’ve made just about every chain style in her book. And she provides an excellent chart that lists minimum/maximum link diameter by wire gauge for each chain type. So that got me to wondering if there might be some similar guidance out there for making a curb chain? For example, if I were working with 12-gauge wire then there’s probably a practical minimal/maximum link diameter required to allow for the links to be twisted while the resulting chain is still supple but not too loose. Does anyone know if this data is published anywhere? If not, I’d sure appreciate some initial suggestions before I start the long process of trial and error until I figure out what works and what doesn’t!
This is something I also wondered when I started making chains. I’m sure there’s an exact formula but here’s how I do it and it’s worked so far. This process is for making a nice tight link with little inter link space.
The main factor that decides everything else is the width you are looking for. Let’s say you want to make a 12mm curb chain. Take an oval link and lay it down flat looking at it vertically, now in your mind divide it into 3 columns, metal, space, metal. Now Ideally if you want a really tight chain, the space should be the same width as the metal on either side. So for a 12mm wide chain you need a 4mm piece of wire(just under 6 gauge) and a 4mm wide space in your link. As far as the length in your link, the link needs to be long enough so the space in the link can have enough room for 2 pieces of your wire plus I generally add 0.5mm extra to account for shrinkage when twisting and still maintain enough room for smooth movement. To find the length your links need to be just take the mm width of your wire and multiply it by 4 then add 0.5mm which would be 16.5mm. That means the space in each link would be 8. 5mm which is just big enough for 2 links to be linked through with space to move.
The next part is finding the correct mandrel which depends on whether you are using an oval mandrel (something I don’t have) in which case you just need a mandrel with the dimensions that your space will be (make sure to account for spring back) or if you’re using a round mandrel and then squishing each link into an oval which is how I do it.
To use a round mandrel, I generally select one that’s 1.5 mm smaller than the length I want my links. So if I want a 16.5mm long link for my 12mm wide chain, I’d use a 15mm mandrel. Once I make all the links and solder em together, I use vise grips which allows me to adjust the amount I squish the links and maintain consistency. All I do is squish all the links so the space is just as wide as the link going through it. Then it’s ready for twisting!
Apologies for the novel but I remember how frustrating it was to try and figure this stuff out not being able to find any information on it. I hope this helps!
What you are talking about when you mention Stark’s chart of Inner Diameter and Wire Gauge is called, in chain maille parlance, the Aspect Ratio. The following link explains what that term means, and gives this formula: Aspect Ratio = Inner Diameter / Wire Diameter
Chainmail 101 | How to Make Chainmail
Knowing this, you can take information in the tutorials for the size (Inner Diameter/ID) of rings recommended and divide it by the gauge of the wire (Wire Diameter/WD). This gives you the Aspect Ratio(AR) used in your Curb Chain tutorial.
Knowing the Aspect Ratio, you can look up whatever other sizes of rings (meaning Inner Diameter and Wire Diameter) also create that particular AR. This link takes you to a chart of each gauge of wire, on the left of the spreadsheet, with the Inner Diameter of various sizes of rings, from 1.6mm to 12.7mm, and the resulting ARs for each combination. So once you know the AR from your curb chain tutorial, you can look for that AR in other gauges and sizes of rings.
Wire and Ring Size Help
There are many chain maille sites that list chain styles by their AR. One very comprehensive site with many different weaves, categorized by where they originated (European, Japanese, etc.), by their AR, with many tutorials is:
https://www.mailleartisans.org
It appears to me that this extraordinary chain maille resource, which is intact and useable, hasn’t had a site manager for 3 years or so, so you can’t register, and some of the search functions don’t work. However, if you go to Home, then Library, you can still access most of their resources. Go next to Weaves, and you’ll get access to the weave types, details, and tutorials as well as a page called “AR Search” which lets you take your selected AR and see the types of chain you can make.
From my research, “curb chain” is a pretty generic term, with lots of variations. I don’t find it named as such on any chain maille site, so it must have originally had a more precise name. However, you can have lots of fun making all sorts of chain maille once you open your vista to all the patterns and variations that are possible. Here are a few other useful resources:
http://www.chainmailbasket.com/
oshuadiliberto.com
Hope this helps!
Marcie Rae
Thank you both for that very useful info! Now I just need to master the flattening of the chain. I’ve tried twisting and using the rolling mill - both with limited success. The twisting technique seems more consistent to me. Although my several attempts have resulted in links breaking at the solder joint, which I’m going to chalk up to my poor soldering skills more than anything else.
I have only made one sample, but after twisting, your links should lay flat in one plane. Stick it down on a board edge so you can file. You can use dop wax or hot melt glue. File with an aggressive file to achieve the curb facet look. If you want a softer edge, round the edges. Allan Revere has instruction in his “Professional Jewelry Making” book. Melissa Muir has a YouTube video demonstrating the steps.