I am building some wiring for an Arduino UNO, probably the same for all of the Arduino products. The two pictures show the box of connectors I purchased and the crimper ordered at the same time.
The problem is certainly in part me and the tremors in my hands, but, I might have the wrong parts.
When bringing the wire, connector, and crimper all together I have to use small needle nose pliers to pre-crimp the little fingers on to the insulator before I can get the wire and socket/pin into the crimper. The smallest crimp option is used. Then after crimping, I had wires slip out. That means I must use the pliers again to post crimp and be sure the connector will not fall off. And then, one of the connectors did not seat in the connector, meaning it can easily be pulled out. It does not get to the point where that little plastic finger clicks down and makes it stay in.
A long time ago, while on active duty, I attended a technician’s school run by NASA people. We called it Arts and Crafts. It covered soldering, crimping, wire-wrapping and other such skills. The crimpers we used there were such that it was held flat, the pin/socket dropped into a round hole in the center, the wire inserted, and when squeezed, the crimper came in from four sides and crimped both the insulation and the conductor. We had to use a specific wire striper to get the striped length exactly right. That was much easier, but probably more expensive than what I have now.
The question is: Do I have the right connectors and crimper? Is there a tip that someone might provide to help me do this better?
Before posting a similar topics panel was displayed showing this tool:
Preciva Dupont Crimping Tool AWG26-18
It looks very much like the one I have but it is different. Then again, a very tiny difference may do the trick. Any recent advice on that one.
I actually intentionally remove the carrier strip prior to crimping (because the edge of the connector will be more smooth if I remove it prior to crimping and sand it down a little bit). It's just that after you remove it it become a bit more difficult to get the header into the crimper
and Usually I will crimp it twice -- I will first crimp a little bit too backward (crimping the front half of the "conductor crimp") and then very tightly against the "rubber crimp" a second time to tighten the "conductor crimp".
There might also be a adjusting nut/plate on your crimper that decides how much force it applies before it "spring back". You might need to fiddle with that a bit.
Crimping is a far more specialized and precise operation than it appears at first glance.
First, the problem could be that your crimpers aren't very good. Crimp dies have to be made specifically for the terminal to work ideally and wire length and wire insulation thickness are critical. That said, I have had fairly good luck with some cheap crimpers, but it's hit and miss.
If you find that you're having to "pre-crimp" anything before you can get the terminal into the die, then that's a problem. It tells me that the die you have is not made for that terminal. Likewise, if the wires are slipping out. A good crimp cold welds the wire to the terminal and should require pounds of force (at least a firm pull) before the wire pulls out.
My basic technique is to put the terminal into the die and squeeze the crimper just enough to hold it in place. Next, put the stripped wire into the terminal, making sure it's at the right depth and that the insulation ends at the right spot.
Then squeeze until the crimper completely closes and the ratchet releases so you can open it again. Inspect the crimp (the book I link below shows what various crimps should look like), and pull gently on the wire, holding the terminal in your other hand. A crimp for wire around 26-22gage should withstand at least a 5-lb pull, ideally a lot more, before it separates.
This book has everything you need to know about crimping and more.
Molex/TE Connectivity actually has a shorter book with good tips about crimping, but I can't find it online at the moment.
Good tips here. You encouraged me to google for this and found much more than expected. Discovered my wire is much too big. Wire on order. Learned to adjust the crimping pressure, and to not put the wire too deep into the connector.
I think the next round will be much better.
Thank you for your time.
I like silicone cables because they are very flexible and very resistive to heat, but they crack very easily (because they are soft).
whereas "hard shell" ones have much more tougher insulation, to which the crimpers are able to grip much better (without tearing it apart), but are not very flexible and cannot take high heat without melting (e.g. accidentally touched on by soldering iron)
That link point to what seems like the silicone cables I was talking about.
FURTHERMORE, there are different ways a crimper can bend the headers to crimp the wires:
I would assume all three crimps are same headers made with different crimpers.
With the extreme majority being the leftmost and only the most extreme exotic ones are the right/middle ones.
Which means that while your headers might be designed with the intent of being used with the middle or the right crimper (and are not used in one) they don't provide optimal results. Even they work with all three.
I have a cheap crimper that does the leftmost crimp and so far I am pretty happy about the quality. However obviously there are better choices and I would hoped I had learned them earlier.
However obviously nobody would want to spend $400 on a old, used Molex "official" DuPont crimper. So ... yeah. At least get the ones without the central "notch", I guess.
You can do whatever you want, but if you want to do things right then abandon ye "dupont" and get with Molex (C-Grid) or resign yourself to the Wonders of GIGO.
After carefully observing the official Molex DuPont (yes, it's by molex) crimper I think you are able to get away by simply grinding away the "notch" on a regular crimper so when closed the cross section is circular, or not as "tooothed". Depend on whether your headers allow a full circular or not.
this only need to be done for the insulation part. the conductor part is okay.
You have the regular "circular crimpers" but we aren't looking for those. We are looking for DuPont crimpers that leave a circular crimp for the insulation of the wires rather than "biting in" and put the majority of stresses on one point.
The tolerances on a properly made crimp die are on the order of single-digit thousandths of an inch. Unless you've had a lot of practice, you're not likely to do a good job by hand.
I think any improvement over the current "bending over and sinking the teeth into the insulation" crimp they provide will be welcomed.
Especially since my headers actually support a circular wrap, and thus when crimped like this provide a lot less mechanical strength. Some of the square sided ones would end up "just fine".
Crimper discussion aside, @bkelly have you found a proper section of wire?
I recommend 24-22 AWG for best results.
Yes, I went to Amazon and searched for wire collections. They have sets of 6 colors / rolls of wires in a collection with varying guages. I ordered several sets of differing size and used some smaller stuff, 26 and 28 gauge. Those work better. We are not far from the Los Angeles area and received some the next day and the others within 3 days.
The proper wire size does indeed matter.
Thank you for your time and your tips.
(looks around the desk for a random DuPont cable)
Well this one I have has .... hm. yes. 28 AWG.
I know the ones on the fan is a bit thicker ... yes. the ones on the case fan are 26 awg.
The proper insulation thickness also makes a huge difference. I used to make wire harnesses for a product I sold. I had the right gauge wire, a quality Molex crimper, exactly the right terminals for my crimper dies, etc. Each box required 52 crimped terminals.
But at least one out of every 20 crimps was failing the "pull test" and I couldn't figure it out. Finally I realized that although the wire gage was correct, the insulation was a few ten-thousandths of an inch too thick for the terminal (the terminal has a max insulation thickness spec) and so it was preventing the die from closing all the way.
Got lucky and found a wire processor that could do the whole job. They could cut and strip wire to length and crimp on my specified terminals all at a lower price than I could buy the bare wire! So I ended up saving money by having someone else do it.
Economies of scale and automatic machinery make a difference.
This generic crimper works great for crimping the bare wire after which you
can hold the wire to insert it into a crimper better suited for the insulation tynes.
You can see the difference. The header is literally the same.
Now, for higher-gauge crimping (e.g. >18 AWG), the difference between a cheap crimp and a expensive (proprietary) crimp is less. Still noticeable, but less significant as long as the wire is good
of times easier as you are in total control over the connector placement.
