Ferrule

The place you're most likely to find a ferrule these days is at the top of a pencil - that little crimped metal bit that keeps the eraser on.

As in, "our famous green and yellow ferrule is your guarantee of quality." So says www.prang.com.

Now you know.

The second place that you are most likely to find a ferrule is on a fishing rod of at least two pieces. The ferrule in this case is the tip of one segment of the rod and the bottom of the other. The bottom end is hollowed out and has a bit of a flair to it. The tip end is designed to fit snuggly into the other end. Not surprisingly, the hollowed out part is called the female side, and the other part is called the male part.

In a fishing rod, the ferrules turns out to be the place where the flex of the rod is "disturbed". A single piece rod flexes continually from top to bottom, depending on the taper of the rod, etc. Where there is a ferrule, the flex of the rod breaks down a bit because it is not one piece.

Most rods are two piece varieties, and have one ferrule. However, there are rods designed to be carried in backpacks and other smaller spaces. These rods will have three, four , or even five segments, and an accompanying number of ferrules.

Yet another meaning for ferrule is the sharp point at the base of a ski pole.

They come in various shapes and sizes, depending on the condition of the snow they're designed for. Powder ferrules are quite broad and blunt, whereas ferrules designed for icy and packed powder conditions are usually quite narrow and sharp.

The point of the ferrule is usually made of some kind of metal, varying from stainless steel to carbide, depending on how much you want to spend.

I'm surprised this hasn't already been mentioned, but a ferrule is the metal bit that holds on to the bristles of a paintbrush. It's the reason why you want to properly clean your brushes since the paint will dry in the ferrule and not clean out too easily or cause the bristles to come out, change shape or lose their spring.

A ferrule is an essential part of a junction of pipes or tubing which carry liquids or gases under pressure. The pipe or tube on one end of the connection is molded or machined to have a concave threaded opening. A compression screw is slipped over the end of the other tube. This is essentially a hollowed out screw that is flat on the end. The hole through the screw has a diameter that matches the outer diameter of the tube passing through it. The ferrule is then slipped over the tube between the compression screw and the end of the second tube. A ferrule resembles a hollowed out cone. The flat base of the cone sits against the compression screw, and the convex side fits into the concavity in the first tube. In some cases the ferrule and compression screw are manufactured as a single integrated part. The screw is threaded into the first tube and tightened, compressing the ferrule and resulting in a connection between the tubes which can withstand high internal pressures without leaking.

                                                         ___
             ___________                     ___________|   |
            | | | | | |             | | | | |               |
           /  | | | | |         _   | | | | |               |
          /                    / |  |_|_|_|_|               |
_________/                  __/  |__|_______|_______________|___
______|                    |__|  |______________________________
                ^             |  |
                |             |  |
tube          threads         |  |     tube interior
                |             |  |
_______         v           __|  |______________________________
______|__                  |__|  |______________________________
         \                    \  |  |_______|               |
          \                    \_|  | | | | |               |
           \                        | | | | |               |
            |  | | | | |        ^   | | | | |___________    |
            |__|_|_|_|_|        |                       |___|
                              ferrule        ^
                                             |
                                          cross section
                                          of compression screw
                                          fitted over end of
                                          tube behind ferrule

Ferrules are commonly seen on pressure regulators where they connect to the valve on a cylinder of compressed gas. Fittings for this type of connection are typically made of brass. The threading of the connection is reversed (turned counterclockwise to tighten) for some gases including acetylene and oxygen.

Ferrules are an essential part of tubing connections for high-performance liquid chromatography. Standard HPLC tubing is made of stainless steel or polyetherletherketone (PEEK) and has an external diameter of 1/16 inch. This tubing is designed to withstand pressures of up to 10,000 PSI, but in the absence of fatigue or chemical degradation of the tubing material, the fitting will always succumb to pressure and leak before the tubing bursts. Like the tubing, ferrules and screws for HPLC applications are also made of stainless steel or PEEK. It is typical to use fittings of the same material as the tubing, but is not necessary. PEEK ferrules and screws (especially one-piece combinations) are often used with steel tubing, but the reverse is not very common. Steel ferrules permanently bind to steel and PEEK tubing when the compression screw is tightened. If it is not seated correctly or the end of the tube becomes damaged, the tube must be cut behind the ferrule and a new fitting made. PEEK ferrules do not bind to either steel or PEEK, so they are easily interchanged. One-piece PEEK ferrule/screw combinations offer the further convenience of providing a finger-tight connection, so no tools are necessary to change a connection. This convenience comes at the price of reduced durability and lower pressure limits before a leak occurs.

Other applications for this type of ferrule probably exist, but are beyond the scope of my knowledge.

The ferrule is the piece of metal that holds the bristles to the handle of a paintbrush. The size, material, and design of the ferrule matter more than you might think!

Stainless steel or nickle plated ferrules are better than ones made from other materials, because they do not rust as much. This is most important with watercolor brushes, as rust on the inside will eventually stain your images. It matters for other brushes as well, because a good brush, treated properly, will last 10, 20, or more years.

The ratio of the length of the bristle inside the ferrule to the amount of bristle outside the ferrule is also important - it affects how firm the bristles are. Brushes with most of the bristle outside the ferrule with be floppier, whereas brushes with more bristle inside the ferrule are more firm. The brushes with the least exposed bristle, brights, are very firm.

It is important to be sure, when painting, to never never never let the paint get down to the ferrules. This is not so important on the outside of the bristles, but moreso on the interior bristles, because it is just about impossible to get the paint out of there. Once the paint dries in there, that effectively becomes the anchoring point of the bristles, and the advantage of having a long ferrule is lost.

In archery, the ferrule is the connecting tube between the shaft and the tip on the arrow. Generally, it is made of alluminum or plastic, and in reusable arrows it is commonly threaded since the tip or shaft often needs to be replaced.

                              ::                                  
                        :==-*@:                                   
                  -++++=  :-                                      
            =++++=      --                                        
      =----:         *+:..:---------------------------------------
    *                         |   Ferrule  |
      =----=.         .*#.::--------------------------------------
            .=+++++.     ::                                       
                   .++++=- .-                                     
                          .=-*@#                                  

The ferrule is one of the most overlooked parts of a pool cue. However, a cue without a ferrule will soon be destroyed since the force of cueing a shot will eventually split the shaft closest to the tip. To forestall this, the end of the shaft is machined (while on a lathe) to reduce its diameter, and a hollow plastic (or plastic-impregnated fiberglass) ferrule is slipped on and secured with glue. Then, both the shaft and the newly-installed ferrule are returned to the lathe and sanded to bring them to the same diameter.

Different cue-makers prefer different styles of ferrule. Some, like Meucci, prefer a long, thin-walled ferrule. Others, like Joss, install shorter, thicker ferrules. In general, a thinner ferrule is preferable, since the glues typically used to install cue tips don't adhere as well to the non-porous ferrule as they do to the wood of the shaft.

Fer"rule [Formerly verrel, F. virole, fr. L. viriola little bracelet, dim. of viriae, pl., bracelets; prob. akin to viere to twist, weave, and E. withe. The spelling with f is due to confusion with L. ferrum iron.]

1.

A ring or cap of metal put round a cane, tool, handle, or other similar object, to strengthen it, or prevent splitting and wearing.

2. Steam Boilers

A bushing for expanding the end of a flue to fasten it tightly in the tube plate, or for partly filling up its mouth.

 

© Webster 1913.