All About Ferrules
Ferrules are the metal parts that are used to join rod sections. Without ferrules we'd be forced to make either single piece rods(which are huge pain in the butt to transport) or cut splices into the sections and then find a way to secure the splices in order assemble the rod. For brevity's sake, I won't go through the history of ferrule development and will only focus on the two major styles that rodmakers are likely to encounter and use today.
Ferrules are most often made from a copper alloy commonly known as nickel silver. In the old days this material was frequently referred to as 'German Silver'. This alloy is composed of 65% copper, 18% nickel and 17% zinc. Adding nickel to make the alloy changes the copper color to silver and adds strength, and zinc gives the metal some 'slip'. Nickel silver is a fantastic choice as a material for ferrules. It is strong, resists corrosion, can be cold formed(precision drawn) into tubes of various sizes, machines fairly easily, can be oxidized(blued), does not gall(gum up) when mating parts slide over each other, and is easily soldered.
In the past, ferrules were sometimes also made from other materials like brass, and chrome and nickel plated brass. Aluminum was also used to a small extent. Today, the vast majority are made from nickel silver, although a smattering are made from silicone aluminum bronze or titanium. One thing that you won't find today are cheap ferrules, which is just as well. We frequently get calls from people looking to repair a broken or worn ferrule on an old low-grade production rod, and they are astounded to learn the cost of a new set of ferrules can easily surpass the value of their 'treasure'. We explain that cheap ferrules are pretty much worthless, which is why they are calling us in the first place!
So, why does a set of quality ferrules seem to cost so much? As I'll later explain in detail, ferrules are made from precision drawn nickel silver tubing. The material isn't cheap to begin with, and a wide range of tubing sizes are needed. The specialized companies that draw the tubing will not draw small quantities, so setting up for making ferrules from tubing requires a major investment in making huge quantities of tubing in all the sizes needed.
Also, drawing of the tubing involves a lot of material science. When nickel silver is worked it is subject to work hardening. If you are not familiar with work hardening, I'll provide an example. Take a piece of wire like a coat hanger. Cut a section and then begin bending it back and forth. As you do this, the metal will first be easy to bend until it begins to work harden. Eventually the wire gets brittle and snaps. The same phenomena occurs when nickel silver is worked. You can start out with very soft nickel silver(annealed) and through working it make it so hard it becomes brittle. This is why you frequently see old cheap drawn ferrules that develop cracks...the metal was either of the wrong temper for the application or became so through overworking in the drawing process and not properly re-annealed. Outfits that draw nickel silver tubing are experts at producing the right sizes and desired tempers. So in just a couple paragraphs I've explained why the raw material costs can be so high, and I haven't even touched on the labor, equipment and machining for making the ferrules from the tubing!
Ferrule Types and Sizes
There are two major types of ferrules available and used today: the 'step down' and 'Super Z-type'. Regardless of type, ferrule sizes are designated by the inside diameter(ID) of the tubing used to make them, expressed in 1/64th on an inch increments. Common sizes for trout rods, for instance, might be 11/64th, 12/64th, 13/64th, etc. Note that in rodmaking lingo, a 12/64th ferrule is referred to as a 64th increment, while a machinist would designate the same size as 3/16ths. As far as ferrules go, the designation is always expressed in 64ths.
Why are the tubing dimensions in even 64th's of an inch? Well, ferrules and the tubing to make them have to be standardized for the parts to be made efficiently, for parts to be interchangeable, and in sizes easily made by available tooling. In addition, 64th increments are suitable enough to make rods of varying line weights and actions with enough variety to fit just about any taste. Smaller increments(say 1/128th on an inch) are simply unnecessary, and larger increments(say 1/32 of an inch) wouldn't be sufficient.
For those new to rodmaking, these decimal and fractional numbers can seem overwhelming but it's easy to find a chart, print it out and post it over your bench. After a short while, you'll be able to rattle off these dimensions and know immediately that .1875 = 12/64ths, for example.
Step Down Ferrules
These are used to a much lesser extent by rodbuilders today, but virtually ALL classic rods used this style. These ferrules fell out of favor(amongst hobbyists, mainly) with the introduction of the Super-Z type, which are easier to mount(slightly) and the perceived design advantages of the type. In truth, there is nothing inherently 'wrong' with the design, and Super-Z ferrules were not invented to fix a design fault in their use on cane rods. (More on that later.)
Here's a set of CSE step down ferrules. As with all ferrules, a set comprises a female and one or more males. The female ferrule is just a straight single piece of tubing. Like all ferrules, the female end has a welt soldered on the end. The welt gives the tubing hoop strength so that the tubing doesn't deform easily under stress. Inside the female and at the ends of the males is a small disc of nickel silver called a moisture plug, which serves to keep water from contacting the ends of the cane sections. Good quality ferrules will also have serration tabs cut into the ends, which allows some flex at the end of the ferrule.
For step down ferrules, the male ferrules are made from two pieces of tubing soldered together. The OD of the smaller piece of the tubing on the males(the slide) that seats in the female therefore must be the same as the ID of the female. This is important for two reasons:
#1) If you need to replace a male ferrule on a rod mounted with step downs, to get the right size all you have to do is mic the male slide and convert it to 64th's on an inch.
#2) If you are taking the taper from a classic rod that is mounted with step downs, it is vitally important to mic the slide of the male ferrule(or ferrules, on 3 piece rods) to find the appropriate ferrule size. It is a huge annoyance that people will take rod tapers without taking this vital information, and can result in having to guess what size ferrule was used.
Here is an example from a classic rod of why this is so important. On this rod, the cane measures .218 just below the female ferrule. Below the male, the cane measures .198. If the taper chart of this rod didn't specify the ferrule size, what ferrule size would you use? Even allowing for varnish, on the female side the cane is closer to a size 14 ferrule(.219), but on the male side the cane is closest to a size 13(.203).
Classic rods often exhibit such a jump across ferrules, and it leads to confusion about the design of step down ferrules. Consider the CSE ferrules again: The ID of the tubing of the female is exactly the same as the ID of the tubing entering the males.
In the case above, micing the male slide determines that the original ferrule is a size 13. So, to mount the female the builder turned down the cane past the point of just becoming round to fit the ID of .203. On the male side, for the larger portion of the male ferrule, the corners were just rounded a bit to .203, and the portion for the male slide was turned down 1/32" further to 11/64ths, or .172. It is very common on old rods for the cane to be turned down severely (by today's standards) in order to fit the ID of the female ferrule. Makers of the time were apparently not very concerned about weakening the cane substantially to do so, and I doubt that it did.
To mount a female step down ferrule, the cane is turned to the ID of the ferrule from the moisture plug to where the serration tabs begin, and then sloped upwards. The male is turned to two diameters: for the portion of the ferrule of the male slide, the cane is turned to its ID, which is 1/32 smaller than the ID of the female ferrule. The next portion is turned to the same ID as the female, and the area of the serration tabs slopes upward as with any ferrule.
It's a shame that people don't use step downs more. From an aesthetic viewpoint, they provide a very low, slim profile and the classic, traditional look of old cane rods. They take a little longer to mount, and are less efficient to produce because a full set requires 5 pieces of tubing and two solder joints(one for each male), while a set of Super-Z styles requires only 4 pieces of tubing and one solder joint.
It's important to understand that the Super-Z style wasn't invented due to some perceived design fault of step down ferrules. Years ago, I interviewed Louis Feierabend, the inventor of the Super Z. Louis told me the reason he invented the Super Z was to solve a problem joining sections of the newfangled fiberglass rods of the time. Think about it: fiberglass rods are hollow tubes, and there's simply no material present in the middle of the tube to turn down to properly mount a male step down ferrule.
Super Z's are sort of the reverse of step down ferrules. The males are straight pieces of tubing like the females of the step down ferrule. The female, however, is essentially just a male with a larger diameter sleeve soldered into place to accommodate the male. The larger sleeve is nicely tapered to make a pleasing profile.
To mount a Super-Z, both the rod sections are turned to the same ID and there is no 'step' to turn for the male. This makes things go a little faster from a production standpoint. Less cane needs to be removed to mount the males, so that area of the rod should be theoretically stronger. However, it's important to remember that although the step area of the male slide on step downs is turned down 1/32" smaller, the cane is surrounded by the nickel silver jacket of the male slide. As noted above, the Super-Z style is also more efficient to produce, requiring only 4 pieces of tubing and one solder joint.
From an aesthetic standpoint, the Super Z present a more bulbous look- the female ferrule swelling out and away from the rod shaft. Still, we use them on the majority of our rods because customers believe them to be far superior and expect to see them present.
One Little Complication!
If you aren't confused enough already, both step down and Super-Z style ferrules are available in truncated versions. These are exactly the same ferrules but made proportionally shorter. These are typically used on 3 piece rods, or on rods for light line weights. The theory is that less weight will impact the rod's action to a lesser extent. The picture below shows the differences in length between a standard and truncated ferrules of both styles, all the same size.(13/64)
Know Your Lingo!
No one wants to look silly by calling ferrules 'ferrets'. Likewise, when you order ferrules you'll want to know the lingo. The size you need is usually specified on the taper chart. If not, find the nearest decimal equivalent. For example: you are making a 7'6" 5 wt ., two piece rod, and at the 45" mark on the taper chart the dimension is .203. Consulting your decimal chart you'll find this corresponds to 13/64ths.
You'll need to decide what type of ferrule you'll want to use, a step down or a Super Z, standard length or truncated, and specify how many males you need. The first number is the size in 64ths, the letter designates the ferrule type, and the next number is how many males you need. Here's some examples of the code:
12S2 = size 12/64ths, Standard Super Z, 2 males
13SDT2= size 13/64ths, Step Down Style, Truncated, 2 males
Copyright 2011, J.D. Wagner, Inc.