Crimps are especially useful, even necessary, with heavy monofilament leaders and cable where knots are not practical. Moreover, knots are subject to human error and with few exceptions seldom retain 100 percent of the actual breaking strength of a given material. Not so with crimps. Once crimp connections are made correctly, they retain 100 percent of the strength of the original material in all but very few applications.
Because crimping lends itself to loops and unions in a range of applications, careful selection of materials, tools and methods is important.
Long Sleeves, Short Sleeves
When crimping wire, stranded cable and coated cable , I prefer figure-eight and round, heavy-walled copper crimping sleeves. These sleeves are available in many finishes - plain, black oxide, and black or silver nickel - but all share the same short-length-to-diameter ratio, about 4-to-1.
With monofilament lines, use figure-eight or oval sleeves. Generally, I prefer aluminum, though thin-walled copper sleeves will also work. Sleeves for mono should have a length-to-diameter ratio of about 6-to-1.
Good, Bad and Ugly: A, coated wire with Flemish loop and well-formed crimp compared to B, a poorly formed crimp. Perfect crimping in heavy mono, C, next to D, E and F, showing uneven compression and lack of flare on sleeve ends. Even compression on cable crimp G is more reliable than crimps H and I, which show careless jaw placement.
The inside diameter of sleeves for mono crimps should closely match the diameter of the monofilament. In fact, the best fit requires a clean cut on the end of the mono. Some nippers and pliers can mash and deform the mono beyond its diameter. Cutters designed for the job create a clean cut that allows the mono to slide into a sleeve that fits snugly.
With multistrand or single-strand wire, a precise fit is less important. In fact, with good tools, technique and setup, one size of sleeve will provide strong crimps for a couple of different sizes of wire.
When crimping monofilament, medium-hard material is the best choice. Very hard mono is difficult to crimp because it will not compress enough for a sound connection. Soft mono can also be a problem because it elongates and shrinks under pressure, and it is more easily damaged by the crimping sleeves.
Special care must be taken when crimping any mono, as it can be damaged with too much pressure. Over-crimping is worse than under-crimping. Wire and cable, on the other hand, are nearly impossible to over-crimp.
Pliers and Presses
The tools used for crimping are as varied as the components. The basic types are simple pliers, compound pliers and compound presses, both hand and bench models. Presses are available with either wide or narrow jaws. Wide jaws perform best with the longer sleeves used with mono, and narrow jaws are better suited for the shorter sleeves used on wire and cable.
Mono from 40- to 150-pound-test will crimp well with simple pliers, but heavier mono requires compound tools. In addition to extra leverage, compound tools also allow jaw and stop adjustments. Bench-type crimpers with either multiple jaw sizes or interchangeable jaws provide the best results, but these are not portable.
With crimping pliers you have to establish a feel for the amount of force needed to do the job. Most compound tools are adjustable and "cam over," or stop, at the end of their stroke to provide consistent crimps.
Crimping tools must be maintained like anything else in a marine environment. Rinsing with fresh water, then thorough drying and lubrication, are essential. A good tip: If you have a rusty "stuck" tool, soaking it overnight in cola will frequently loosen joints and restore the tools to their former function.
Setup for Success
For initial setup with heavy mono, once the appropriate components are selected, set the crimper so that it pinches off the mono in the crimp. Then back off the pressure adjustment a half turn to a full turn, crimp another sample and test it carefully. This should be a good starting point with most combinations of tools and components. From there you may need to make small eighth-turn adjustments to reach that magic 100 percent strength. A properly swaged crimp on mono should have a small bell on either end of the sleeve, which helps prevent chafing.
Wire and cable crimps require high compression, and these materials are far more forgiving of extreme pressure than monofilament. Therefore, compound tools are best for wire. Of special note: Coated cable will seldom retain 100 percent breaking strength unless crimps are made in conjunction with a Flemish eye or figure-eight knot.
Test Your Crimps - Carefully
You may do your own testing with a come-along or other method with the required strength, but be careful, especially with monofilament. Testing to failure can be very dangerous (*see below). Once you have a sample that fails outside the crimp, make 10 more sets and retest to be certain. You should also retest at least once a season or when any component is changed.
Today, many tackle shops have testing equipment that can help confirm your results. It is best to consult with someone in the know. Most dealers are more than willing to help you get set up to build reliable crimp connections. And most will already have a base line of components and combinations available. A lot of time, money and effort can be saved at your local full-service tackle dealer.
About the Author: Frank W. Johnson III, vice president of Mold Craft Fishing Products in Fort Lauderdale, Florida, began rigging artificial squid when he was 14 years old. Throughout the past 25 years, he has overseen the production and rigging of millions of trolling lures and teasers for Mold Craft's worldwide market.
If you choose to test your crimps to failure, be aware of the forces you'll be unleashing. Most mono will stretch 40 percent before breaking, and any material will rebound violently when it parts. A piece of 400-pound-test mono, stressed to failure at 400 pounds, when stretched one foot releases 400 foot-pounds of energy. This is similar to a hot .357 Magnum round. If you are intent on this type of testing, keep well clear of your samples as you test them.