Picture of How to Make A Quality Crimped Joint
Whilst understood well within professional harness makers, the correct application of crimps is something that doesn’t seem to be as widely understood in DIY circles with much information available ranging from not very thorough to out-rightly wrong; One of my friends was once given the advice by an employee in a car hi-fi shop to hold the crimp onto the cable with insulating tape and nothing else....... Crimping is a technique that can produce reliable, long lasting joint, efficiently and easily with very little training.

There are a vast range of crimps out there in the market- industrial users of crimps have good access to information from the crimp and tooling manufacturers so I won’t go into depth on these applications. Instead, in this Instructable I hope to give some advice on using crimps that you are likely to encounter in installing accessories or making repairs to your car, boat or caravan or in projects at home.

Much of this Instructable will focus on materials and tools, so I will split this down into detail in three main areas and will keep the introduction materials simple:


Good quality crimp terminals to suit the application

Stranded wire of a known specification (not solid core)



Good quality wire strippers

Crimp tool to suit the terminals

AlanS141 month ago

Good for one particular audience - beginners . Too lightweight by far-for almost everyone else, it's a very basic primer at best.

superpants (author)  AlanS141 month ago

Perhaps you'd like to write a detailed Instructable?

It's a subject that can easily fill a book, and has. The best book imho is the out of print one you mention. Why don't you write one?

argos0903 years ago
Can I ask why not just solder wire with a $10(or less) butane torch?

Crimps are superior in several ways for many applications not least of which is lower resistance than soldered joints.

superpants (author)  argos0903 years ago
There are many reasons why a crimped joint may be used, and indeed may be preferable to a soldered (or indeed screwed joint). The common advantages are:

Higher reliability of joint in many cases, especially in vibration or high temperature applications.
No heat involved so safer to use in many cases- especially in confined spaces, or near flammable materials
Equipment highly portable- especially compared to soldering equipment for larger cables
No heat damage of insulation possible, or solder wicking up conductor
A mating half to an existing connector may only be available in crimp style
Lower level of skills training required for a user to achieve consistent results
For production users, ease of automation & integration of process controls for quality
It is easy to correct wiring errors by removal and re-insertion of contacts in a housing

There will of course be many applications where a soldered joint is preferable, but I hope that this Instructable helps people make an appropriate choice.
superpants (author) 9 months ago

Muzk- thanks for the kind comment!

superpants (author) 9 months ago

Jim- You are right, thanks for noticing! I have updated the page.

MuzK9 months ago

Dear thanks for providing such a nice guide on wires crimping, it helps me lot.

jim.lastella11 months ago

For 10-12 AWG terminals I think you meant the insulation will be yellow, not red.

mucool1 year ago

Hi! Thank you so much for the detailed guide on crimp terminals. No where else I could find so much info. I recently built a circuit and now I want to upgrade a few capacitors. I am not able to pull the crimp terminals from the connectors (these are soldered on to the PCB http://www.digikey.com/product-detail/en/1285/1285...)

If i try too hard, the crimp insulation cover comes out (pink plastic). Is there a trick you have up your sleeve or any tools you'd recommend. The wires coming out of the transformer are short, and cutting them every time is not an option. Thanks!

6 - tranny connects.jpg
RangerJ2 years ago
Very good Instructable. I appreciate that you provided sufficient detail to make it understandable.
superpants (author)  RangerJ2 years ago
Thanks! Always good to get feedback.
Technosteve3 years ago
twisting the wire will cause crimp faliure and can do so by nearly 60% in some tests during calibration testing using hellerman crimps and tools.

The correct colour crimp tool is thefore paramount to a good crimped connection.
The manual crimp tool that indents the crimp and is usually found as a kit in car parts places those without a ratchet will quicly fail as the insulation will return to its former shape and can slide off the crimp, they can also deform the crimp badly leading to cable faliure usually as a result of over crimping.

I would recommend always using the ratchet type as shown in the pictures.

When looking at the closed crimpers you will see one side is slightly larger then the other this is the insulation side of the cimper and the smaller deforms the metal part of the crimp with this type the insulation does not relax as much over time.

a good instructable none the less.
dchall83 years ago
It seems I could follow your Instructable and still do it wrong. You go into mind numbing detail all the way up until you finally stick the crimp fitting into the tool. It seems to me that the only thing that matters, assuming you are somewhat close in mating the wire to the fitting, is the part you were vague about. Which way do you put it in? Is there a right way and a wrong way? Does it matter if the fitting is sideways or upside down?

It looks like there are many ways to make a crimp, at least by looking at the last picture. Is the same tool used for all of them?
superpants (author)  dchall83 years ago
Thanks for taking the time to comment. One of my aims in writing this Instructable was to make it clear that there is far more to making a reliable crimp than often thought- I’m therefore disappointed that this is seen as ‘mind numbing detail’. On re-reading that section, I can see that I do need to expand it a little to ensure orientation & cavity size is properly covered and will do so.

I have earlier in the Instructable indicated that the correct tool for the crimp needs to be selected to suit the crimp- so no, the same tool cannot be used for all of them.
pcooper23 years ago
A properly executed crimp joint will be mechanically and electrically more reliable than a soldered joint. The key to an acceptable crimp joint is that it must be "gas tight" -- the metal of the wire and the crimp lug are pressed so intimately together that if it were the lid of food can, it would be an hermetic seal. To get the best joint, the crimp lug should be matched closely to the wire gauge: The stripped wire should just slip into the lug with minimal side-to-side play. The crimping tool is important as well, as the most inexpensive tools found in automotive supply stores tend to crush the crimp lug and not properly compress it around the wire. Unfortunately, industrial crimping tools can be quite expensive, costing hundreds of dollars apiece, and one may need several different tools for different sizes and styles of lugs and terminals.

Avoid cheap knock-off crimp lugs from China and other moderately disreputable places, especially if they are to be used in automotive or aviation applications. The brand-name lugs and terminals from western European and North American suppliers will cost more, but are worth it in the long run by avoiding joint failures later.
pecker3 years ago
Excellent instructable.
I'd agree! Buy a ratchet crimper.The cheap "squeeze and pray" type of crimper will either chew your terminal, leave bare wire exposed or not grip properly.
superpants (author)  pecker3 years ago
Thanks a lot for the kind comment facklere, senorbutt & pecker!
magickaldan3 years ago
Your suppose to put the dimple of your crimp tool on the opposite side of the seam on a crimp connector. Unless the seam is brazed then it doesn't matter what orientation you put the crimp tool on.
superpants (author)  magickaldan3 years ago
Absolutely right- In the example in the photo this is a brazed seam crimp, wher I wanted to show the indent.
facklere3 years ago
Excellently written and illustrated. This topic was always a bit foggy to me, but now I feel like I have a good beginner's knowledge. Thanks!
senorbutt3 years ago
Very well written and informative, thanks!