IWISS SN-025 Ratchet Crimper AWG28-18 for Dupont,Molex CP,C-Grid 0.1-1.0mm2

I want to preface this review by saying that I'm just a hobbyist and I'm using this for non-professional applications (RC planes). Prior to this, I had no experience with crimping cables. I finally got fed up with using pre-crimped jumper cables and never having the exact length that I needed, so I tried my hand a crimping the cables myself (Dupont 2.54 mm pitch / 28 AWG wire). So many of the online tutorials made this seem surprisingly difficult, but I'm really happy with the results from this tool and how quickly I was able to get it dialed in. It took me about 6 or 7 unsuccessful attempts to figure out the pressure, but I was eventually able to get consistent crimps.The tension for the final ratchet 'click' is adjustable. After the last click, the tool will release. I think this was very useful for a novice like myself to figure out how much pressure is needed. My advice is to squeeze down juuust enough to get the tool to release (you'll see the release lever go down), and then check to see how the crimp came out. Do the pull test. If the connector easily slides off, increase the tension. If the insulation is visibly over tightened (it looks like it's oozing through the gaps of the connector) -- or worse, it completely splices the cable -- then decrease the tension. The actual tension needed might be somewhere between two of the settings. For me, I need to squeeze just a small bit more after the release lever goes down.My last bit of advice to other novices is to make sure that you strip the proper amount of insulation off of the wire. Keeping the insulation out of the conductor-crimp zone is key to getting a successful crimp, and you don't want the stripped wire in the insulation-crimp zone. It's not a huge deal if some of the stripped wire extends beyond the conductor-crimp zone and towards the mating pin zone, but obviously don't leave an excessive amount. After you strip the wire, just take one of the connectors and check to see if you wire lines up properly (stripped piece of wire extends from the top to the bottom of the conductor crimp zone). Place the connector in the tool, ratchet down until the connector is being held, and then lay your wire down. Check that you can see your wire reaching the top of the conductor crimp zone, and then complete the crimp.

The SN-025 is great for the price for crimping Amphenol mini-pv ("Dupont") connectors, which require an M shaped crimp instead of a round one. The real Amphenol tools are much, much more expensive, like over $1000. Even if the SN-025 crimps aren't as perfect as with a genuine tool, at least these work infinitely better than any of the more commonly found budget tools that only have a round crimp.The other comparable tool to consider would be the Engineer PA-24. (Note that the much more popular Engineer PA-09 is terrible for Dupont connectors--despite the advice you will find online, you should only use the PA-09 for things that require a round crimp, like JST connectors.) The PA-24 is harder to find and more expensive than the SN-025. The main difference between the two is that the SN-025 crimps both the wire and insulation at the same time, while the PA-24 requires you to crimp one after the other. Since I own both, I find that I end up using them both quite often. For instance, I'll use the tip of the PA-24 to pinch the wings of a mini-pv connector so that it fits better into the SN-025, and if something goes wrong with my SN-025 crimp, often I can sort of fix it up using the PA-24. Nonetheless, if I had to have only one, I'd probably go with the SN-025.

I do a lot of automation work using Arduino and Raspberry Pi for things like sensors, fans, etc. I'm OCD about having perfect cables/connections. I have tried five crimp tools and even after dialing in the right crimp pressure and inspecting every crimp and making sure the insulation crimp was flat but often have the last insertion in the housing blow out the sidewall of the housing or ruining the crimp trying to force the pin into the housing.I read an article the other day on hackaday.io about using the proper tool for the job and the author recommended the $425 manufacturer's tool for the perfect crimp. Way too expensive for my needs. Realizing that, he recommended this crimp tool as second best.It turns out, most low cost crimp tools form an elliptical crimp making it hard to insert the pin into the housing. It also seems to spread the sidewall of each position out so the last position would blow out the side wall. The uneven force of an elliptical shaped crimp can also increase the resistance of the connection.This crimp tool is different in that the shape of the jaws makes for a more circular (cylindrical) crimp even on the insulation part of the crimp.I received this tool yesterday and this morning started to make some test crimps on 26 and 28 awg wires. When I pushed the pins into the housing, they just slipped in so easily I couldn't believe it! All of the latches were evenly closed which I sometimes had to live with questionable latching if I knew the connector wouldn't be disturbed and not have anyone pulling on the cable. When I flipped open the latch, the pin slid out as easily as it had slid in!Although it might not be the "perfect" tool for dupont connectors but I didn't have one bad crimp in all of my test crimps.