Well this has sent me down quite a rabbit hole!
After reading this data sheet https://docs.rs-online.com/e1e0/A700000007538105.pdf I sourced these 22-26 AWG ultra-high spring force female crimp contacts:
300 47649-000LF Mini-PV female tin at £0.092 each, reel strips of 100;
200 48236-000LF Mini-PV female 30u gold at £0.268 each, loose in bags of 100.
Both were ordered from RS.
How have you fared with the reeled contacts? People generally recommend avoiding reeled Mini-PV because they’re reeled end-to-end (not side-by-side like most contact types), meaning you have to make two accurate cuts per contact to dereel them.
Firstly, apologies for the delay in responding.
Yes, reeled contacts are a PITA to split out, but they were (relatively) cheap and locally available in the tinned version ultra high spring force. The gold plated versions were available loose, I'm saving those up for a rainy day.
Meanwhile, regarding the crimping tool, I came across these two blog posts:
https://www.mattmillman.com/a-new-budget-dupont-crimp-tool-is-bought-to-my-attention/
https://www.mattmillman.com/iwiss-sn-025-another-head-scratching-dupont-crimp-tool-lands/
I've never had a particularly satisfying relationship with crimping tools, part of it is no doubt the quality of the cheap tools that you find paired with bulk assortments of connectors, and it now seems that the crimping tools I have were never going to work well with Dupont crimp connectors anyway due to the "B" style crimp around the strain relief as well as the wire crimp itself. It seems obvious now, but the strain relief part of the crimp really needs to be a round "O" crimp.
Yep, that’s one key element of a proper DuPont crimp: the o-shaped insulation crimp. A B-shape crimp there runs the risk of damaging the insulation (creating a weak spot where the insulation will break) and often a crimp too wide to fit into the housing properly.
That website is a great resource I have linked to in the past in other DuPont crimping threads. I am so envious of his collection of crimp tools!!
I've found myself accumulating quite a few myself now! An Engineer PA-24 came my way a few days ago, it's quite small and lightweight as crimping tools go, but needs two actions for each crimp, one for the strain relief and the other for the connection itself. It does have both B and O crimps. I haven't tried it other than a couple of test crimps yet, so the jury's out. Although it needs two actions, it may be less fiddly than trying to align a connector in a dual-action crimp tool.
The PA-24 is explicitly designed for: JST PH, NH, XH; Molex 43030, 1560; TE EI; and Amphenol QI/Dupont.
The PA-24 O crimpers are 1.4 and 1.8mm. The B crimpers are 1.3, 1.6, 1.9 and 2.2mm.
Both TE EI and Dupont use O crimps on the strain relief.
Regarding the looseness and durability of the contacts, it's early days, but so far after multiple insertion cycles it is very clear the tin Mini-PVs are going to last longer.
One thing to note is that the tin Mini-PV contacts I have don't fully cover the length of the header contacts they're mating with, leaving a couple of millimeters uncovered. I'm not sure that this is a problem as the fit is so much firmer than the generic Dupont clone contacts I have been using.
I never realised there is so much folklore around crimping, and I am sure I have plenty more to learn.
Yeah, you’ll find that the Mini-PV doesn’t get loose in any noticeable way, after the first insertion.
Since this thread, I’ve had a chance to try Harwin M20, and despite those contacts looking identical to generic Chinese DuPont contacts, having the exact same one-piece folded construction, they perform far better than the generic ones.
As for the insertion length:
1. headers come in various lengths. You may want longer ones.
2. Make sure you’re stripping to the correct length. If you strip too much, the overhang sticking out of the conductor crimp can interfere with the pin. The overhang should be around 0.3-1mm. I aim for 0.5mm.
And I wouldn’t refer to it as “folklore” — most people don’t realize that crimping is a precision metalworking process. The “rules” are the result of 70-odd years of industry experience and metallurgy research.
I might get some M20 too. I already got hold of some Molex C-Grid III to try, but they don't seem to have different spring force versions.
I tried using a dynamometer to measure any force degradation over repeated cycles, but it'll need an automated jig: doing it by hand is a waste of time, it's not possible to get repeatable results.
Regarding my "folklore" comment, that's been my perception, purely down to the apparent lack of canonical information available.
I did replace all the single flying lead terminations of one AD2 cable assembly, reusing the existing 1x1 housings, which have thus far shown themselves to be good enough for the job.
Regarding getting just the right strip length, I use a Jokari PWS-PLUS 002.
PWS-PLUS 001, Mfr# 40024, 26-36 AWG, white thumb push
PWS-PLUS 002, Mfr# 40025, 20-30 AWG, red thumb push
PWS-PLUS 003, Mfr# 40026, 18-28 AWG, blue thumb push
Be aware that Knipex also sell a seemingly identical PWS-PLUS 001 and PWS-PLUS 003. These are not the same! Most importantly, unlike the cheaper Jokari versions, the Knipex versions don't have a guide that goes down to the very short strip length required for these crimp connections. You can still strip with the Knipex versions, but you'll usually find that you have an extra step of trimming after stripping.