This article is intended to demonstrate methods of classifying rings by their primary attributes (metal type, ring inner diameter, wire size and resulting aspect ratio, and weight), which make them ideal for chainmail use, and the collection and recording of this information. Also, this article will consider variables which will affect ring sizes, which include springback. Regarding aspect ratios, specifically it will discuss how they affect chainmaillers, and their role in weave studies. Detail is gone into on the proper use of a vernier caliper to measure the inner diameter and wire size of a ring. I highly recommend reading the articles listed in the bibliography (located at the end of the article) to supplement the information provided herein.
Strictly speaking, there are five pieces of information to store about each ring type. These include its metal, the thickness of the wire used, the listed ring size (mandrel size used to make the rings), the measured (actual) ring size, and the weight of the rings. Type of metal includes the metal itself (such as stainless steel, bronze, aluminum, etc.) as well as the alloy and temper, if that information is available. Wire size is usually known when you buy wire. For our purposes, it must be specified using actual units instead of one of the (despicable!) wire gauge systems. This information is usually available through the wire supplier, however, due to wire size tolerances, it's important to measure the wire instead of using the measurement the supplier provides. Listed ring size is specified by the size of the mandrel on which the coil was wound. A ring that is cut off a coil wound on a 5/16" mandrel is classified as a 5/16" ID (inner diameter) ring. Of course, the ring itself will not have an exact inner diameter of 5/16" due to variables that come into play during the ring manufacturing processes. (These variables are explained in the next section.) The ring will have an actual inner diameter which will be slightly greater than the listed value. The actual ring size (inner diameter) will be listed using the same unit as the wire size. The weight of a ring type can be stored as either number of rings per pound, or kilogram, or any other weight or mass unit, for that matter.
A ring will always be slightly larger than its listed ring size. This is due mainly to a thing called springback.
As defined on zlosk.com, springback is defined as follows:
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According to www.dictionary.com, springback refers to: "a flying back; the resilience of a body recovering its former state by elasticity; as, the spring of a bow", or, in our case, a coil of wire. When winding wire on a mandrel into a coil, the coil unwinds a little bit when tension on the wire is released. This results in the rings having a slightly larger ring I.D. than originally anticipated. The type of material used, tension on the wire while coiling and speed of coiling are some of the factors involved in springback, making it difficult to come up with a common number that everyone can use. Material seems to have the greatest impact on springback. |
On top of this, the ring cutting method will also have an effect on the actual ring size of the resulting rings. Thus, it is important to control as many ring manufacturing processes as possible for any batch of a specific ring type to ensure consistency. What this boils down to is the fact that one chainmailler's rings of a certain metal type and size will NOT be the same as those of another mailler.
A sixth piece of information about a ring of a certain type is its aspect ratio. A ring's aspect ratio is a calculated number based on the ring inner diameter divided by the wire size. To calculate this, you must use measurements of the same unit. Usually this unit is inches or millimeters. Before you can determine the aspect ratio of a ring, you must find its actual wire diameter, and actual inner diameter. These are found by measuring the ring using a caliper.
Measuring rings is an activity that will require a special tool called a caliper. Calipers vary in quality. Better quality calipers will yield more accurate measurements. In the field of chainmail study, the desired precision should be that of one thousandth of an inch (0.001") or roughly 0.025mm for those who use the metric system. The caliper in the picture (model # DCH-S-6 from Victor Machinery Exchange) measures to this precision. It has a dial readout, and thus is a dial caliper. Some calipers contain an LCD matrix display, and are called digital calipers. If you are planning on getting a caliper for chainmail study, make sure it is one that has the capability of measuring inside diameter as well as the outside measurement of an object. Luckily, most models do.
Hold the ring such that one edge is exposed and put that between the outside caliper jaws. Bring the outside jaws together so that they push against the wire, but don't force it or you could damage the caliper. Now observe the readout section for your measurement and record. In this situation the ring is made out of .063" stainless steel wire, and the readout displays this. The dial points to 63, and the number that precedes that is the 0 right next to my thumb.
The mandrel on which this ring was wound measures 5/16", or .3125". To measure the actual inner diameter of a ring, you place it over the inside caliper jaws then pull the caliper out until each jaw touches opposite sides of the inside part of the ring. The dial readout displays 46, and the main scale reads 3, thus the actual inner diameter of this ring is .346"
Data was collected and recorded for two ring types for this tutorial to be used as examples. The first ring type (as used in the caliper use demonstration) is 1/4 hard temper, 304 stainless steel, 5/16" ID, .063". The second ring type is full hard temper, 5356 aluminum (bright), 3/16", .062". The inner diameter of 25 rings of each type were measured and recorded, then their average found. Measuring just one ring won't give you accurate data. Even though you are controlling the ring manufacturing processes as well as possible, there are still tolerances experienced. Why do we measure 25 different rings? Because 25 is the magic number of trials that will give you statistically accurate information. This is by no means a set standard, it is simply the standard to which I, personally adhere.
A good tool for recording this type of information is the use of a spreadsheet. That way you can plug in the formulas for finding the average measured inner diameter (actual ID), ideal aspect ratio, and actual aspect ratio.
| Stainless Steel: 304, 1/4 hard | Aluminum: 5356 (bright), full hard | ||
|---|---|---|---|
| 5/16" | .3125 | 3/16" | .1875 |
| .063" | .063 | .062" | .062 |
| Trial# | Result | Trial# | Result |
| 1 | .343 | 1 | .205 |
| 2 | .343 | 2 | .205 |
| 3 | .349 | 3 | .202 |
| 4 | .351 | 4 | .205 |
| 5 | .345 | 5 | .206 |
| 6 | .350 | 6 | .204 |
| 7 | .343 | 7 | .207 |
| 8 | .344 | 8 | .206 |
| 9 | .344 | 9 | .207 |
| 10 | .344 | 10 | .206 |
| 11 | .347 | 11 | .203 |
| 12 | .350 | 12 | .206 |
| 13 | .348 | 13 | .204 |
| 14 | .345 | 14 | .209 |
| 15 | .343 | 15 | .205 |
| 16 | .345 | 16 | .201 |
| 17 | .343 | 17 | .204 |
| 18 | .349 | 18 | .203 |
| 19 | .345 | 19 | .202 |
| 20 | .347 | 20 | .205 |
| 21 | .351 | 21 | .205 |
| 22 | .349 | 22 | .206 |
| 23 | .348 | 23 | .209 |
| 24 | .344 | 24 | .202 |
| 25 | .343 | 25 | .205 |
| Actual ID | .346 | Actual ID | .205 |
| Ideal AR | 5.0 | Ideal AR | 3.0 |
| Actual AR | 5.5 | Actual AR | 3.3 |
Due to the fact that we're dealing with approximate numbers (measurements), we must round the results to the proper number of significant digits. This means using the same number of significant digits as the figure in the equasion with the lowest number of significant digits. To calculate the actual aspect ratio in the two cases above, using the equasions (.346/.063), and (.205/.062), the wire size only has two significant digits in each case. Thus we round the answer in each case to two significant digits (5.5, and 3.3, respectively).
One of the main areas where properly measured rings and calculated aspect
ratios are very important is in study of chainmail weaves. For every weave, there will be a range of aspect ratios that will work, and at least one range of aspect ratios that won't work. Rings with an aspect ratio that is too small for a weave to be constructed are those which fall below the minimum AR for that weave. In very rare cases with certain weaves, if your rings have an aspect ratio that is too high, the weave will not work. These rings are said to fall above the maximum AR for that particluar weave. In most cases, there is no maximum AR for a weave; the larger the AR you use, the looser the weave becomes. Rings that cause a certain weave to either have a desired look, flexibility, or function are said to have an "ideal" AR for that particular weave. For every weave, there is an ideal AR range. This will differ significantly from weave to weave.
How do you find the ideal AR for a weave, and/or its practical or absolute minimum AR? One method is to look the information up on the Internet. Just remember to check whether or not the source of the information was derived from actual ring inner diameters, or listed ring inner diameters. One such resource is the last listing in the bibliography (bottom of page). Another, and much better method of finding the ideal, practical minimum, and/or absolute minimum AR is through experimentation. This means trying out the weave using various ring types that you've already measured, and recording the information (whether or not the weave works, and how well) for further use.
Once you have a known aspect ratio information for a particular weave, you can determine what ring size to use if you want to try the weave using a different wire size. As an example, lets say you have found the Full Persian weave made with 5/16", .063" stainless steel rings to be ideal for your use. These rings have an actual aspect ratio of 5.5. If you want to try the weave using .048" wire, then the equasion (5.5*.048) will tell you that you need to use rings with an actual inner diameter of about .26". How do you know what ideal inner diameter will yield rings with an actual ID of .26"? By trying to make rings on a mandrel that is slightly smaller than .26". The size of mandrel to use will vary somewhat depending on the metal type you plan on using, due to variance in springback. Let's say for example you plan on using stainless steel. From my personal records, my 1/4", .048" stainless steel rings have an ID of about .278", and my 7/32", .048" stainless steel rings have an ID of roughly .243". Thus I can calculate that if I were to make stainless steel rings using a 15/64" rod out of .048" (I haven't yet, as of this writing), they will have an actual ID of approximately .26", and bear the same approximate AAR as the 5/16", .063" stainless steel rings. If your mandrels are in larger increments, you can round up or down as you see fit, bearing in mind that the resulting tightness of the weave will vary accordingly.
For most people, storing the ring information should be done on some kind of table, or using a spreadsheet. If a spreadsheet is used, a chart such as this one should be considered:
| Metal type: | Ring size: | Ideal Ring ID | Actual Ring ID | Wire size: | Ideal AR | Actual AR |
|---|---|---|---|---|---|---|
| Stainless steel, 304, 1/4 hard | 5/16" | .3125 | .346 | .063 | 5.0 | 5.5 |
| Aluminum, bright, 5356, full hard | 3/16" | .1875 | .205 | .062 | 3.0 | 3.3 |
A better way of storing and managing this information is the use of a relational database. This is currently what I am undergoing the implementation of. I have found that the following table structure provides an adequate means of storing all ring information. The tbl_ prefix signifies a table, and the fld_ prefix signifies a field.
+------------------------------------------------------------------------------- | tbl_ring | fld_ID (INT, auto increment) (primary key) | fld_metal_type_ID (INT) (foreign key, points to tbl_metal_type) | fld_wire_size_ID (INT) (foreign key, points to tbl_wire_size) | fld_inner_diameter_listed_ID (INT) (foreign key, points to tbl_inner_diameter) | fld_inner_diameter_actual (decimal, 0,3) | fld_rings_pound (INT) | | tbl_metal_type | fld_ID (INT, auto increment) (primary key) | fld_name (varchar) | fld_description (varchar) | fld_alloy (varchar) | | tbl_wire_size | fld_ID (INT) (primary key) | fld_size (decimal, 0,3) | | tbl_inner_diameter | fld_ID (INT) (primary key) | fld_inner_diameter (varchar) | fld_inner_diameter_size (decimal, 0,4) +-------------------------------------------------------------------------------
The sample data from above is presented:
| tbl_ring | |||||
|---|---|---|---|---|---|
| fld_ID | fld_metal_type_ID | fld_wire_size_ID | fld_inner_diameter_listed_ID | fld_inner_diameter_actual | fld_rings_pound |
| 1 | 1 | 63 | 20 | .346 | 907 |
| 2 | 2 | 62 | 12 | .205 | 4280 |
| tbl_metal_type | |||
|---|---|---|---|
| fld_ID | fld_name | fld_description | fld_alloy |
| 1 | stainless steel | Stainless steel is an alloy of... | 304, 1/4 Hard |
| 2 | aluminum, bright | Bright aluminum is an alloy of... | 5356, Full Hard |
| tbl_wire_size | |
|---|---|
| fld_ID | fld_size |
| 63 | .063 |
| 62 | .062 |
| tbl_inner_diameter | ||
|---|---|---|
| fld_ID | fld_inner_diameter | fld_inner_diameter_size |
| 20 | 5/16" | .3125 |
| 12 | 3/16" | .1875 |
This article covered ring classification by their inherent attributes, as well as the storage of this information. Also presented were discussions on aspect ratios and how they are calculated, as well as the use of a vernier caliper to measure ring sizes.
| zlosk.com: Everything You Ever Wanted To Know About Aspect Ratios But Were Afraid To Ask | Exactly what the title says. This well written article describes in detail aspect ratios, as well as springback. |
| M.A.I.L.: Aspect Ratio Studies | A look at how to collect and calculate exact ring size data. Also contains information on determining the practical minimum and absolute minimum AR's for a weave via trial and error. |
| zlosk.com: Aspect Ratio Chart | A table of weaves and which AAR's will and won't work. A lot of the more common weaves are listed. Some values are calculated, while others were collected from actual trial. |