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[on:]

I've created a board that has 2-pin, 3-pin and 4-pin 0.1" male headers that are all meant to connect to off-board components like other boards, LEDs and potentiometers. I ordered some housings from Digikey that fit my headers just fine, but I'm having a really hard time getting the crimp contacts to fit!

Here is an example of the 4-pin housing that I got: http://www.digikey.com/product-detail/en/0022013047/WM2002-ND/26435
And here are the crimp contacts, which are listed as an Associated Product for the housing above: http://www.digikey.com/product-detail/en/1375819-1/A100453CT-ND/2233146

I am using solid core wire from an ethernet cord (24AWG I believe).

I can get the contact crimped to the wire just fine, but when I try to insert it into the housing there is significant resistance. Even when I take pliers and push hard, all that happens is the crimp contact snaps in half!

Is there another tool I need to make this work? Maybe the crimp contacts are not good for my housings (even though they are an Associated Product on Digikey)? Does anyone have some info about how to assemble my own cables like this?

Or is there maybe a better interconnect solution that I don't know about to get off-board components wired up?

[Reply #1 on:]

I may be missing it in the associated product list. The first thing that caught my eye is that the housing and pins you linked are from different manufacturers, which doesn't mean they don't work together, but...

FWIW, I find connectors a huge pain. Very difficult to find just what I want, mating parts, etc., especially when places like Digi-Key or Mouser list about a million part numbers. Real needle in the haystack.

[Reply #2 on:]

Looks like your housing is Molex series "KK® 2759" and the pins are TE Connectivity series "CST-100 II". Probably best to stick with one manufacturer and series.

[Reply #3 on:]

I find the crimp terminals, crimp terminated wires, and crimp housings from pololu.com all work well together.

For ribbon cable/IDC, I've been getting parts from phoenixent.com.  Lot easier to find stuff vs buried at digikey/mouser.
Getting ready to make up 28 cables to connect a breakout board to 28 dual-7-segment display boards.

digikey does have a good selection of JST connectors, I've designed the 1.5mm, 2.5mm, and 3.5mm pitch connectors, both thru hole & surface mount, into several boards (2,3,4,5,6,8 pin variants). Someone else ordered the mating JST female header with wires, we crimped pololu pins onto the flying leads and put them into crimp housings to mate with AVR ISP programmers, USB/Serial boards, and other boards.

[Reply #4 on:]

Great responses, thanks. It looks like the 2 and 4 pin housings I ordered were from the KK series, while the 3-pin housings were from the CST series. When I went to order the crimp contacts, I grabbed contacts that were associated with the CST series, not the KK series.

I've decided to go with bare male headers so that the housings don't need to be polarized or have anything fancy on them (locking ramps, friction lock, etc.). I found housings such as the following in the KK 2695 series: http://www.digikey.com/product-detail/en/22-01-2031/WM1576-ND/1090454

The following crimp pins are in the Associated Products list: http://www.digikey.com/product-detail/en/0008500113/WM1114CT-ND/467980

But the crimp pins are in series KK 2759 series. I have a hunch that the numbers are less indicative than the letters (KK), but does anyone know for sure what that naming scheme is about?

[Reply #5 on:]

Update: making custom cables sucks!

The crimp contacts and housings appear like they would mate, but every time I crimp a wire on and try it insert it, more often than not the wire snaps off. The specs for the contacts say they work with 20-26AWG, but my 22AWG hookup wire doesn't seem to fit. Thin solid wire taken from ethernet cables (I think 24-26AWG) bends very easily and snaps.

This process appears really straightforward, but is turning out to be the most frustrating part of assembling my project! Am I doing something wrong, or is custom cable assembly best left to machines and factories?

[Reply #6 on:]

Just takes practice.
Gets better as you do it more often.

If you decde that's not going to work out, these wires & housings from pololu.com are easy to assemble.

http://www.pololu.com/catalog/product/1903
http://www.pololu.com/catalog/product/1800
http://www.pololu.com/catalog/product/1804

[Reply #7 on:]

Thin solid wire taken from ethernet cables (I think 24-26AWG) bends very easily and snaps.

No no no no. You need braided wires.

What tool are you using to crimp?

[Reply #8 on:]

I use Molex connectors on a lot of my projects.  Sometimes I don't know if they're worth the effort.  They're expensive, a pain in the butt to work with, finding the right pins can be a hassle, and twice now I've ordered a bunch of stock parts that later become discontinued before I've used up the mating ends.  UGH.

Definitely use stranded wire.  The mechanical grip on those tiny pins just won't work well with solid core.  Since the pins usually have "flaps" that fold over from the sides, I usually use pliers to get them started, so they're bent over the wire.  Then I use one of those Radio Shack crimping tools with the nub on one handle and the slightly larger recess on the other side.  This pushes the two flap ends into the wire.  Not as nice as the photo in the previous post, but they seem sound enough.

I'd love to have one of the nice specialty crimpers to produce a nice bind like that picture, but the price of the official tools is downright ridiculous.  If I ponied up $200 or more for a crimper and then had to abandon my stock when Molex decides to stop producing that part, I'd rage-quit electronics.  If in doubt, just add a touch of solder.

[Reply #9 on:]

I'd love to have one of the nice specialty crimpers to produce a nice bind like that picture, but the price of the official tools is downright ridiculous.  If I ponied up $200 or more for a crimper and then had to abandon my stock when Molex decides to stop producing that part, I'd rage-quit electronics.  If in doubt, just add a touch of solder.

I don't have the correct crimper either, and I usually end-up soldering. 

[Reply #10 on:]

I sprung for a pololu crimper. $35
http://www.pololu.com/catalog/product/1928
for these pins
http://www.pololu.com/catalog/product/1930
http://www.pololu.com/catalog/product/1931
The female pins fit nicely in Arduino female headers.

My wife is a wiz with it - even solid core 22 guage wire.

Don't know if it'd comparable to any of these
http://www.king-cart.com/phoenixent/product=TOOLS+FOR+INTERCONNECTS+%2526+WIRE/exact_match=exact

[Reply #11 on:]

Molex makes a hand tool that works quite well for crimping their pins.  $34 at Mouser:

http://www.mouser.com/ProductDetail/Molex/63811-1000/?qs=sGAEpiMZZMtArvHj40ttL4Zoic5nRoqx93Wc1uWgp6E%3d

You will also need an insertion tool appropriate for the housing that you are using.  It works wonders stuffing your pins into your housing.  I use this for SL connectors;  don't know what is recommended for KK:

http://www.mouser.com/ProductDetail/Molex/11-02-0022/?qs=sGAEpiMZZMtVoztFdqDXO2Ur2jARPc6r

(the Mouser picture for the latter is incorrect)


And of course use stranded wire as has been already mentioned...

[Reply #12 on:]

I go to Newark for my pin headers (Multicomp) as they are dirt cheap. I also get the crimp pins from there too. I had been using needle nose pliers and soldering. I just got an Engineer PA-09 crimper that does a fantastic job (even on sold core which I know is non-ideal).

This is like (if not exactly) the connector I usually get in bulk: http://www.newark.com/harwin/m20-1180046/connector-contact-female-22awg/dp/96K4323.  I ordered a batch of housings a while ago and don't remember the brand by you might look at Harwin or anyway the same manufacturer as the crimp connectors.

[Reply #13 on:]

The page that opens here
http://www.newark.com/harwin/m20-1180046/connector-contact-female-22awg/dp/96K4323
shows the same kind of things that pololu carries.
Pololu has better prices, and various sizes are easily accessed.
http://www.pololu.com/catalog/product/1930
http://www.pololu.com/catalog/product/1931
http://www.pololu.com/catalog/product/1904

[Reply #14 on:]

Those are good prices! Multicomp at Newark is better. But less convenient to find stuff. Pololu is awesome.

The multicomp pins are only $3.20 / 100 -- although shipping probably breaks the deal.

http://www.newark.com/multicomp/2226tg/contact-socket-28-24awg-crimp/dp/08N6834?in_merch=Popular%20Products&in_merch=Popular%20Products&MER=PPSO_N_C_EverywhereElse_None

The Multicomp housings are cheaper too. 4x1 are $0.38 / 10. But Newark tends to cost about $6-ish to ship US. I think Pololu has cheaper shipping. And, again, they are awesome.

http://www.newark.com/multicomp/2226a-04/wire-board-conn-receptacle-4pos/dp/08N6815?in_merch=true&MER=ACC_N_L5_Connectors_None