Mini-Type Self-Adjustable Six Mandrel Ratchet HSC8 6-6 Crimper Plier For Wire Terminal Connector 0.25-6mm2 Multi Hand Tools (WHL #40)
Software stuff aside, back to hardware. And by hardware, I actually mean hardware. Tools. Let’s check out some crimping pliers for wire ferrules. Automatik-Aderendhülsenpresszangen, as we Germans like to say. 
The unit in review was bought late February on AliExpress for 14.94€ including shipping (which took only around two weeks). When I showed it at work, I needed to order another one with the same specifications (14.89€ in early April, delivery took 3 weeks) and one with four mandrels, but 10mm² capability (HSC8 family as well, 12.13€ mid-March, two weeks). I’m sorry if that already takes away the excitement for my conclusion, but that’s how popular these pliers are.
To make things a bit more interesting, I decided to run this pair of pliers against the type that we typically use at work, which is model 6101863 (“610 186 3”) from Rennsteig, a German quality tool brand. Apparently, these also go by the name of PEW 8.186 . These puppies start at around 130€. Other major players like Cimco, Knipex and so on charge you around 100€ to 250€ for similar tools. So how good can a Wan Hung Lo cheapy be?
Turns out, a few cents extra would make a better product. It’s not terribly disappointing and it’s easily fixed by a dab of hot snot, but the handles wobble around a bit. So I removed them, pre-heated the pliers with a hot air gun, put in a bit of hot glue into each handle and put it back together. Feels rock solid now.
For comparison, this is the Rennsteig tool:
While coloring is quite similar (usually the Rennsteig tools are pale greenish with blue accents – not sure if that is an old design?), it’s not a total ripoff in terms of construction. The china part may be based on a different brand product, but it’s too dissimilar with this one.
Mandrel construction – Wan Hung Lo:
Mandrel construction – Rennsteig:
Looking much fancier, but it’s just the result of having a shiny finish instead of the blueing of the entire tool.
I have to add that the China cheapy still has a bit of play, which is due to the length of the studs not perfectly matching the total thickness of the handle parts. Have a look at the lower right locking ring – you can see a few tenths of a millimeter that allows the tool to move a bit. The Rennsteig for comparison is built like a brick dunny.
Now, let’s crimp some ferrules…I went with quite a variety of types:
From left to right:
* 6.0mm² aluminium (yellow DIN sleeve color)
* 6.0mm² copper
* 4.0mm² copper (grey)
* 2.5mm² copper (blue)
* 1.5mm² copper (black)
* 0.5mm² copper (white)
* 0.22mm² aluminium
* 0.14mm² copper
The last two carry the wrong ferrules, these are 0.34mm² types and they should be 0.25mm² (yellow) and 0.14mm² (grey) instead – but I don’t have these at home, and neither do we have those in stock at work. So I usually don’t crimp these, but instead I solder them on. For these small wire diameters it’s more important (for me…) to have a bit more material to work with, as these strands are tiny by definition. Having a tight, full-area grip with a connector isn’t such big of a deal, as you would not use 0.14mm² wire for any sort of power transfer application anyway. It’s just to keep the leads in place. Aiming for the same thing, my colleague actually bought these weird 0.22m² wires to replace 0.14mm² – little did he know that these are aluminium instead of copper. So if you run the numbers, it turns out that wire resistance is actually pretty identical – but with the benefit of more volume, hence easier handling.
That’s the first round of crimping. All ferrules WITH the protective sleeve have been crimped using the Rennsteig tool. All ferrules WITHOUT are Wan Hung Lo. These are the same ferrules, I just used some snips to remove the sleeve before crimping. So any difference in the crimps is not due to different ferrule properties, but it’s from the pliers working differently.
Also, important to note: After some preliminary tests, I set the adjustment wheel to position 5 of 6, I think it is shipped on position 1, which is clearly too weak. The crimping action gets noticeably heavier, but that’s what it needs to be if you deform metal. The Rennsteig tool is fully automatic and cannot be adjusted as far as I know. Which turned out to be detrimental, but first things first.
The 0.14mm² doesn’t get crimped properly at all. Yes, the ferrule might be at fault here, but the tool is rated from 0.08mm² to 10mm². It doesn’t crimp enough to keep the ferrule attached. And I tried hard to pull them off, as seen by the piece of 0.5mm² wire that lost the entire insulation in the process. Doesn’t work with straight strands, doesn’t work with twisted ones.
The 6mm² aluminium is also a bit short under the ferrule, but I redid that after the following incident. While I was trying to figure out how to get a microsection (is that the correct term for wires as well?), I had some fun with the Dremel. I used the saw to remove half of the ferrule and tried to whet it down to a nice even surface. Well – the vibrations by the Dremel caused the ferrule to slip off 
Broken strands from between the crimping points can be seen above. In the second trey, there’s crimping marks visible on the corner strands…but not enough pressure applied to keep the ferrule in place.
Redid that a third time – holding “well” this time. One more wire without insulation. Still, frightening to have a crimping tool that does not work properly in some cases!
Second round – now the China tool:
0.14mm² did work and I was not able to remove it by hand. And that’s even with the tool stating 0.25mm² to 10mm², so it’s technically not even suitable for that task!
Preparing the microsections is a bit tricky for 0.14mm² and 0.22mm². One slight stroke over the file with a misaligned ferrule and it snaps right off. That’s surprising given I couldn’t tear it apart, but i guess the crimp reduces the tiny sectional area too much for that task – see the images below. So it might just snap off above the first crimping point, and that’s it. I guess I’ll stick with soldering, even tinning the leads does help tremendously in enlarging the wire diameter.
Just FYI – that’s the mess I created while filing down each end of the wires, which turned out to be the easiest and most reliable way to get a clean, polished end:
So, now the hard part: Wiggling at each wire, trying to bend the leads and get the ferrules off once again. No tools used, just wild hand movements. You shouldn’t do this to your wires, but any good crimp should withstand this torture. Let’s see the contestants:
6.0mm² aluminium (yes that looks like copper, but that’s residue from the copper ferrules that is smeared over the surface when whetting. Clearly looking aluminium-ish when cut):
I’d say we have a clear winner – the Wan Hung Lo product. Both ends have some warping, but the WHL crimp looks elastic to me, they all move in a group. The Rennsteig crimp however has strands that move vastly different to their neighbours. The Rennsteig web page linked above actually has some microsectional images as well, and this result is pretty much what they advertise. But – shouldn’t it be squeezed together so that you get hexagonal strands that go into close packing configuration?
6.0mm² copper: (sorry, now two images for every wire, it’s too hard to get both ends in focus at the same time)
Even worse! The entire wire slips out of the ferrule once again. I tried hard, but I couldn’t do anything to the WHL crimp, even though it has some air pockets on the sides, meaning there already is less than 100% contact to the ferrule walls. Still, the Rennsteig crimp loses…
4.0mm² copper: Same thing with the Rennsteig. WHL does now move a bit, but it’s not drawn out significantly.
2.5mm² copper: I’d say we’re about equal now. Both crimps could be better, but no wire got loose.
1.5mm² copper: Rennsteig loses once more, a few strands were pulled out. The WHL crimp barely moved at all.
0.5mm² copper: These are equally perfect. No movement in both cases. I’m so lucky using 0.5mm² at home all the time 
0.22mm² aluminium: Rennsteig ferrule removed entirely…
0.14mm² copper: Same. As I said, I wouldn’t trust these crimps due to the reduced wire area which makes them quite brittle, but if there’s one pair of plies that can do 0.14mm², it’s the China one.
Wan Hung Lo wins 8:2 – at a price of 1/9th of the “Made in Germany” tool.
That’s
a) super awesome for the China tool
b) hugely worrying for every crimp that is done at work with a “professional” tool like the Rennsteig pair of pliers.
I already reported these results back and we’ll run a few comparisons with the different tools that are in use. Again, you usually wouldn’t wiggle around the wires after a crimp, but having ferrules fall off under vibration within seconds or being able to remove half of the ferrule by hand isn’t intended behaviour of a wire ferrule. Glad I’m the idiot that tests working place equipment at home at his leisure…well, I had a recent score in the dumpster, so that’s fine by me
