What are Crimping Tools?
Crimping tools (crimpers) mechanically compress a terminal, splice, or connector onto a stripped conductor to create an electrical or mechanical connection. A correct crimp forms a cold weld between conductor strands and the barrel of the terminal, providing low resistance, pull strength, and vibration resistance without solder.
How do crimping tools work?
Crimpers use matched dies to form a controlled profile around the terminal barrel. When the handles close, the dies deform the metal to specific dimensions that meet the connector’s specification. Ratcheting models lock until the full cycle is reached, ensuring consistent compression; manual/compound models rely on the user to reach full force.
Which types of crimping tools are there?
- Ratcheting crimpers – Full-cycle mechanism for consistent results and repeatability. Often feature interchangeable dies for insulated/non-insulated terminals, ferrules, and coax.
- Manual/lever crimpers – Lightweight, simple tools for general terminals and on-site work; good for occasional crimps or tight spaces.
- Heavy-duty crimping tools – Long handles or compound action for large cable lugs where higher force is required.
- Dedicated die crimpers – Fixed die sets for a single connector family; fastest when you use one style all day.
What wire gauges and terminals can I crimp?
Most general crimpers cover common ranges such as 22–10 AWG insulated terminals; heavy-duty tools handle larger conductors for lugs and splices. Always match three things: conductor gauge, terminal type/barrel size, and the die profile recommended by the terminal manufacturer.
How do I choose the right crimping tool?
- Identify terminal style (insulated, heat-shrink, non-insulated, ferrule, butt splice, ring, spade, coax, etc.).
- Match the wire gauge range printed on the tool or die to your conductor size.
- Select mechanism – ratcheting for repeatability; manual for portability; heavy-duty for large lugs.
- Confirm die compatibility – interchangeable die sets expand coverage for future projects.
How do I use a crimping tool correctly?
- Strip insulation to the length specified by the terminal (no nicked strands).
- Insert the wire fully into the barrel until strands are visible at the inspection window (if present).
- Place the barrel in the correct die color/size and orient the seam per the tool’s marking.
- Close the handles through the full cycle; ratcheting tools will release at the correct force.
- Inspect the crimp: tug test, verify symmetrical compression, and apply heat-shrink if used.
What are common crimping mistakes to avoid?
- Using the wrong die size for the barrel or wire gauge.
- Not completing the full ratchet cycle (under-crimp) or using pliers instead of a crimper.
- Over-stripping or nicking strands, reducing pull strength.
- Crimping on insulation when the terminal is designed for conductor-only compression.
How should I maintain crimping tools?
- Keep dies clean; remove adhesive residue from heat-shrink terminals.
- Lightly oil pivot points; store tools closed to protect dies.
- Periodically verify with pull tests for critical assemblies.
Crimping Tools — Frequently Asked Questions
What’s the difference between ratcheting and non-ratcheting crimpers?
Ratcheting crimpers lock until the dies reach the calibrated compression, improving consistency and reducing user variation. Non-ratcheting models rely on operator feel and are lighter and simpler.
Can one crimper handle insulated and non-insulated terminals?
Yes—if the tool supports interchangeable dies or has multiple labeled die nests. Use the die profile specified for your terminal style to achieve the correct compression geometry.
Do I need separate tools for ferrules?
Ferrules require square, hex, or quad-crimp dies designed for ferrule barrels. Some ratcheting frames accept ferrule dies; check the die set specification.
How do I know the crimp is good?
Perform a firm pull test, verify full die impression, and check that strands are fully captured with no exposed copper beyond the bell mouth. For critical work, compare to the terminal maker’s crimp height or go/no-go gauge.
When should I choose a heavy-duty crimper?
Use heavy-duty or compound-action tools for larger lugs and cable sizes where higher compression force and longer handles are necessary to meet pull-out and resistance requirements.