Crimp With Confidence


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Photo: Steve Dougherty

Round Sleeves

Material: Brass
Required Crimping Tool: Point-to-Cup
Reliability: Fair

Notes: Achieves relatively decent connection in light tackle applications, but not intended for big game applications. Most often used when crimping titanium leader.

Oval Sleeves

Material: Aluminum, brass or copper
Required Crimping Tool: Cup-to-Cup
Reliability: Excellent

Notes: Common on commercial fishing vessels and an excellent choice for serious recreational anglers. When appropriately sized and compressed with the correct tool, oval sleeves create reliable connections offshore fishermen can count on.

Double Barrel Sleeves

Material: Aluminum, brass or copper
Required Crimping Tool: Cup-to-Cup
Reliability: Excellent

Notes: Double barrel sleeves, especially the heavy wall variety, create a neat joint with absolutely no danger of the leader crossing over itself. While more costly than oval sleeves, double barrel sleeves are less prone to over crimping and thus user-friendly for novices.

Swivel Sleeves

A variation of round sleeves, swivel sleeves come in various sizes and are primarily used to attach branch lines to the main trunk line on multiple hook deep drop rigs. Swivel sleeves should be crimped with a small cup-to-cup tool.


The most commonly used crimping tool, cup-to-cup crimpers have opposing jaws with matching semi circular cutouts. There are usually multiple sized cups depending on the tool, and jaws include markings to indicate the appropriate cutout to use with each size sleeve.

Standard duty cup-to-cup crimping tools typically accommodate oval sleeves up to 2.2 mm diameter, enough for 300 lb. test monofilament leader. For recreational anglers this should be all you ever need. If you need to crimp anything larger, heavy-duty big game cup-to-cup crimping tools are the way to go. While more costly, big game crimping tools are manufactured to greater standards and are capable of compressing heavy-duty sleeves as large as any offshore angler will ever need.

Bench crimpers are desired because of their ease of operation, but not suitable for rigging in the field. These tools often feature the same jaws as big game cup-to-cup crimping tools but can also feature interchangeable die sets for specific crimping applications. In either case, bench crimpers have large handles and are mounted in place to facilitate crimping mass quantities of sleeves.


Resembling a large pair of pliers, point-to-cup crimping tools are relatively inexpensive and feature semi circular cutouts on one jaw, with a series of pointed teeth on the opposing jaw. Used only with round crimp sleeves, point-to-cup crimping tools make an inadequate connection and are not recommended for big game applications.

Crimping Monofilament

Select the appropriate sleeve for your monofilament leader. Sleeve packages indicate proper sizing information relative to line diameter measured in millimeters. For monofilament applications, sleeves can be aluminum, copper, brass, oval or double barrel. Choose whatever you prefer, just make sure the crimp has a snug fit over the monofilament leader while still capable of sliding freely.

Pass the tag end of the leader through the sleeve and through a piece of chaffing tube. Insert the tag end into your terminal tackle, if applicable, and form a loop by passing the tag back through the sleeve in the opposite direction. Snipping the end of the leader on an angle helps with inserting the tag back into the sleeve.

With crimping tool in hand, select the appropriate cut out to accommodate the selected sleeve. Position the sleeve between the jaws of the tool so that the round cups fit around the curved edges of the sleeve. Squeeze tightly, essentially compressing the metal around the leader. Longer sleeves may require that you slide the tool along the sleeve and compress once or twice more along its length. I start at the top, move to the bottom and finish in the center. Do not crimp to the very end of the sleeve as this may cause the edge of the compressed metal to cut into the softer leader. Ideally, the ends of the sleeve should be flared with a minimal buffer at each end. It is almost impossible to use too small of a crimp, in which case it simply won’t fit over the mono, but you can choose too large of a crimp for the desired application.

Crimping Cable

The process involved with crimping cable is much the same as crimping monofilament, with a couple of important reminders. Do not use aluminum sleeves. Only choose brass or copper sleeves, whether oval or double barrel. Also, do not leave an excessive tag end of wire or it will come back to bite you.

Common Mistakes to Avoid

Do not crimp all the way to the end of the sleeve. Instead, leave a 1/16 inch buffer at each end.
Do not use aluminum sleeves on wire or cable leader. This corrodes the alloy and quickly weakens the connection.
Do not use the wrong size sleeve. The purpose of crimping is to compress the metal sleeve around the line, so be sure to select an appropriate sleeve that fits snuggly around your chosen leader material.
Do not use the incorrect crimping tool for the selected sleeve.
Do not use the correct tool incorrectly. With cup-to-cup crimping tools, pressure is applied by the curved surfaces of the cups against the curved surfaces of the sleeve.
Do not leave a long tag end protruding from the sleeve. With mono this looks messy and snags weed. With cable or wire, a tag end can cut you when handling lines.