Crimping cables isn’t rocket science—but doing it well? That takes a bit of know-how. If you’ve ever ended up with a wonky connection, intermittent signal, or a plug that pulls right off, you’re not alone. The good news is: those problems are totally avoidable. Whether you’re working on Ethernet, coaxial, or telephone lines, mastering the cable crimping tool can save you hours of frustration and boost your professional cred.
Let’s break this down so you can crimp like a pro.
What Is a Cable Crimping Tool?
A cable crimping tool is a handheld device used to join a connector to the end of a cable by compressing (or “crimping”) it into place. The end result should be a solid, secure, and electrically-sound connection that won’t come loose under pressure.
There are different types for different jobs:
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RJ45 crimpers for Ethernet (Cat5e, Cat6, Cat6A, etc.)
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RG6/RG59 crimpers for coaxial cables
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RJ11 crimpers for phone lines
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Insulated/uninsulated terminal crimpers for general electrical work
For this guide, we’ll focus mainly on RJ45 (Ethernet) cable crimping since that’s where most people run into issues.
Tools and Materials You’ll Need
Here’s what should be on your workbench:
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Crimping tool with cutting and stripping blades
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Bulk Ethernet cable (Cat5e, Cat6, etc.)
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RJ45 connectors (8P8C)
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Cable stripper
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Wire cutters
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Cable tester (optional, but recommended)
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Boot covers (optional, for extra protection)
Know Your Cable: Solid vs. Stranded
Before you cut a single wire, figure out what kind of cable you’re working with.
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Solid core: Better for long, in-wall runs. More stable signal but less flexible.
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Stranded core: Better for short patch cables. More flexible, but slightly weaker signal strength.
RJ45 connectors are usually specific to either solid or stranded. Using the wrong type? That’s a recipe for loose connections and future headaches.
Step-by-Step: Crimping RJ45 Ethernet Cables
Let’s walk through the full process, step by step:
1. Measure and Cut the Cable
Cut your Ethernet cable cleanly using wire cutters. Make sure the cut is straight. Frayed or uneven cuts can make the next steps messy.
2. Strip the Outer Jacket
Use the stripper section of your crimping tool or a dedicated stripper. You want to remove about 1 inch (2.5 cm) of the outer sheath.
Pro tip: Don’t nick the inner wires. It’s easy to cut too deep and damage the copper inside.
3. Untwist and Arrange the Wires
You’ll see 4 twisted pairs (8 wires total). Untwist them gently and straighten them out.
Then, arrange them in one of two wiring standards:
T568B (most common for home networks)
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Orange/White
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Orange
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Green/White
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Blue
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Blue/White
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Green
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Brown/White
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Brown
T568A (less common, used in some commercial settings)
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Green/White
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Green
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Orange/White
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Blue
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Blue/White
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Orange
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Brown/White
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Brown
4. Trim the Wires Evenly
Line them up flat and trim the tips so they’re all the same length—about half an inch (12–13 mm) from the jacket. You want them to slide into the connector cleanly and evenly.
5. Insert the Wires into the RJ45 Connector
Hold the plug with the clip side facing down. Carefully insert the wires into the connector, making sure they stay in order and go all the way to the end. The copper ends should be visible through the front of the plug.
Double-check:
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All 8 wires are in the correct order
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They reach the front of the connector
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The outer jacket is inside the plug (so the strain latch can grip it)
6. Crimp It
Place the connector into the crimping slot. Squeeze the handles firmly—don’t be gentle. You should feel a solid “snap” as the pins pierce the wires and the strain latch bites down on the jacket.
Don’t double-crimp. Once is enough. Re-crimping weakens the connection.
Optional: Use Cable Boots
If you’re making patch cables that’ll get plugged and unplugged often, slide on a rubber boot before crimping. It helps reduce wear and tear on the plug and gives the cable a more polished look.
Test the Cable
You don’t want to find out the cable doesn’t work after everything’s installed.
Use a cable tester to verify:
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Each wire is properly connected
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There are no shorts, opens, or crossed wires
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The connector is secure
Common Mistakes and How to Avoid Them
❌ Mismatched wiring standards
Pick one (usually T568B) and stick with it on both ends. Mixing them creates a crossover cable, which might not work in your setup.
❌ Wires out of order
It’s easy to get a pair wrong. Always double-check the sequence before crimping.
❌ Wires too short or not fully inserted
You want full contact between wire and metal prongs. If they don’t reach, you’ll get intermittent signal loss.
❌ Not using a proper crimping tool
Pliers won’t cut it—literally. A real crimper makes precise, reliable connections.
❌ Weak crimps
If you’re too gentle, the pins won’t fully pierce the insulation. Squeeze hard. This isn’t the time to be dainty.
Pro Tips for Better Crimping
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Practice on spare cable before doing your actual run.
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Label your cables on both ends—it saves you from guessing later.
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Use high-quality connectors; cheap ones often lead to failed crimps.
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Invest in a good tool—the difference between a $10 and $30 crimper is night and day.
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Keep your blades sharp to avoid crushing or nicking wires.
When to Replace Your Crimping Tool
Even good tools wear out. Here’s how to know when it’s time to replace yours:
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Blades no longer strip cleanly
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Crimps feel weak or inconsistent
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Handles feel loose or unresponsive
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It physically hurts to use it (bad ergonomics = long-term hand pain)
If any of those ring true, retire the tool before it ruins a critical connection.
Final Thoughts
Crimping isn’t glamorous, but it’s the backbone of every wired network. A bad crimp can mean the difference between blazing-fast speeds and unexplained dropouts. Once you’ve got the hang of it, you’ll move faster, make fewer mistakes, and deliver cables that actually last.
So grab your tool, trust your hands, and get crimping.
Because once you know how to do it right, there’s no reason to ever settle for “good enough.”
