Following on from my recent review of the Preciva PR-3254 crimp tool, I hit up eBay and Amazon to see if any other such tools may have surfaced lately. I found one:
We have a new tool (Amazon UK link), which is also apparently specifically designed for these contacts.
At the time I wrote this article, the SN-025 is not (yet) listed on IWISS’s website? IWISS now have a product page for this tool.
A little bit of context
SN-025 is a particularly unusual crimp tool because it has ‘O’ shaped insulation crimpers. Some contacts (for example “DuPont” type) require a tool like this for correct crimping however historically almost no generic hand tools with this type of die had been available.
In the decades since imitation DuPont Mini-PV connectors first surfaced, hobbyists instead had to resort to mutilating contacts in unsuitable tools like the one above on the left. Only those in possession of either the DuPont-designed hand tool (extremely expensive) or the appropriate automated applicator had been able to crimp them correctly.
The above graphic is provided by the Amazon seller, specifically pointing out that it wraps the insulation around the wire. It’s almost as-if they’ve been reading my crimp connectors page…
While this is being sold as a “DuPont” crimp tool, it appears it is predominantly designed for Superseal contacts. Not something I’ve ever used myself, but no doubt commonly used in the automotive space.
- AWG 28 for “DuPont” contacts
- AWG 20 for Superseal contacts
- AWG 18 for Superseal contacts
The AWG 28 die
Let’s put some “DuPont” contacts in there and see what we end up with:
Of course SN-025 wasn’t going anywhere near the HT-95’s crown as ultimate “DuPont” crimp tool. (Since writing this article I have come across a slightly better tool for these contacts). It did do marginally better than the Preciva PR-3254 I reviewed previously.
The SN-025 not having an AWG 24 die, it over-crimped the insulation as we would expect, and the wire part isn’t crimped anywhere near as tight as it is supposed to be – typical for Chinese tools.
The other two dies?
The marketing image typically attached to this tool features a mystery contact crimped onto AWG 22 wire. Whatever it is, I don’t have one, but it doesn’t matter because I’m only looking at the crimps. Let’s put some AWG 22 wire and a similar sized contact in the AWG 20 die and see if we can re-create it:
Nope. The insulation crimp is far too loose, not gripping at all, so that picture is hogwash. Let’s see what else we could potentially use those dies for…
I went through my crimp tool cupboard to see if I had any others like this. Of the, err, considerable number (I’ve lost count) of manufacturer original tools in my collection, just seven have an ‘O’ type insulation crimp. Only two of those were in this wire size range:
An interesting type to compare against because Multimate contacts look quite similar to the one pictured in the image the tool is sold with. Given how esoteric these are, no point in going any further into that.
A common type stretching to AWG 20 wire size, which has an ‘O’ crimp. More about these here.
KK .396 (?)
In addition to the “DuPont” types, Molex KK .396 (.156″) is offered as a supported contact type. Not something the average hobbyist is going to be reaching for. I’ve got the manufacturer original tool for these, it’s not quite an ‘O’ type crimp, but let’s give it a shot anyway:
Mini-Fit Jr (?)
The die in the manufacturer original tool is quite similar to the KK .396 tool, so we’ll look at these too.
- Top: AMP E.I. contact crimped in SN-025 AWG 20 die
- Middle: Molex KK .396 contact crimped in SN-025 AWG 18 die
- Bottom: Molex Mini-Fit Jr contact crimped in SN-025 AWG 18 die
Certainly not one for E.I. It was OK on the wire part but it didn’t touch the insulation crimp.
For KK .396. Pretty good! the insulation part is a smidgen too loose on AWG18 wire, even when crimped in the AWG 20 die (forget it for AWG 20 wire). The results do not match the marketing image, I can only assume that was done by a different tool. Or, perhaps, the marketing image is depicting a smaller KK .254 contact?
Last but not least, the results for Molex Mini-Fit Jr looked quite good, so I’ve taken a closer look:
AWG 18 wire crimped by 3 tools. On the left a typical result of a budget tool, with the insulation deeply pierced due to the very long tabs on these contacts.
For the SN-025 crimp on the right: It takes a bit of practice, and the lack of a bell mouth has cut the wire a little, but otherwise the SN-025 has yielded a result very similar result to the Molex 63819-0900, correctly and cleanly wrapping the insulation support. The SN-025 doesn’t have the needed asymmetry in the insulation crimper to allow the tabs to easily fold over each other, but it they seem to most of the time when I tried it.
While I have shown it used for E.I, KK.396 and Mini-Fit Jr, this is purely experimentation, and I would emphasise that the manufacturer does not recommend this tool for these connector types.
For “DuPont” contacts, which are officially recommended, it does significantly better than other tools generally used by hobbyists, however as always my recommendation is that this tool (and any other tool in this price bracket) should only be used for applications in the “fun” category, specifically the kind of fun that doesn’t involve someone losing an eye when it goes wrong.
I have detailed a number of other tools to consider on this page.