Modern replacements for Molex KK connectors

My bulk buy of a box of various Molex  KK connectors (20+ years go) is more or less empty. I just use them for prototyping on 2.54mm pitch strip board. Any suggestions for a more modern replacement. Preferably smaller quantities and from RS or Farnell

Hi Martin

I am a great fan of KK connectors.  I use them on most projects and haven't found anything to better them for small signal interconnects.  Even the Chinese ones on eBay are quite good as there is not that much to go wrong with them.  Although I do 'touch solder' them after crimping.

I would suggest getting another box load if you can.

Best regards

Mike

Thanks Mike,

I still like them, but I get confused by all the different crimp contacts that don't fit. I just don't like buying a pack of 10 or 50 crimp contacts to find they are wrong, again, and will outlast me, in my junk box

Martin Griffith said:

My bulk buy of a box of various Molex  KK connectors (20+ years go) is more or less empty. I just use them for prototyping on 2.54mm pitch strip board. Any suggestions for a more modern replacement. Preferably smaller quantities and from RS or Farnell

Click to expand...

The MTA-100 are pretty cool.....

https://www.youtube.com/watch?v=uRiZFxZz_7Y

Martin Griffith said:

My bulk buy of a box of various Molex  KK connectors (20+ years go) is more or less empty. I just use them for prototyping on 2.54mm pitch strip board. Any suggestions for a more modern replacement. Preferably smaller quantities and from RS or Farnell

Click to expand...

Stick with KK. I often buy small quantities of these from RS or Farnell for work where they are the standard small signal etc connector system.
Correct crimps should be easy to identify but I will try post part numbers later when in the office.
Do you have the hand crimp tool ?

Newmarket said:

Stick with KK. I often buy small quantities of these from RS or Farnell for work where they are the standard small signal etc connector system.
Correct crimps should be easy to identify but I will try post part numbers later when in the office.
Do you have the hand crimp tool ?

Click to expand...

CRIMP HOUSING: MOLEX 22-01-2035  2.54MM  3WAY
        FEC 143127
                RS 2964940

CRIMP CONTACT: MOLEX - 08-50-0032
          FEC 9773789
          RS 467598

hit send early there...

Molex KK 4809 Crimp Terminal Contact, Female, 0.05mm² to 0.35mm², 30AWG to 22AWG, Tin Plating

slightly cheaper @ Farnell (looking from UK).
Also CPC (Part of Farnell) also have alternative 'equivalent' LEOCO products (Taiwan from web suffix) that are a lot cheaper.  Enter the MOLEX part number into CPC and it goes to LEOCO crimp. Not tried them.

Do you have the hand crimp tool ?

Click to expand...

I got the Waldon, neolithic crimper

I’ll be the stick in the mud. I don’t like KK connectors. Any connector that moves around makes me really nervous. When things break 99%  of the time it’s a connection.

I just had to break out my stash and crimp tool to connect to some Mean Well PSU’s. If it was mission critical I would have soldered to the connectors. This is for a bench power supply that won’t move so I’m using them.

I like the Phoenix terminal blocks. They come in the same pitches as KK so they fit.  For prototypes they are great because you have access to individual wires. When you use ferrules you can connect and disconnect as many times as you want. They are more expensive though.

Martin Griffith said:

I got the Waldon, neolithic crimper

Click to expand...

OK. I use this type (but it's a work tool so I didn't have to pay :

https://www.molex.com/molex/products/datasheet.jsp?part=active/0690080955_APPLICATION_TOOLIN.xml&part=active/0008500113_CRIMP_TERMINALS.xml

but it's now 'obsolete' and replaced by :

https://www.molex.com/molex/products/datasheet.jsp?part=active/0638118200_APPLICATION_TOOLIN.xml

The first one looks better ergonomically to me but the ratchet return on both of the ones I use has started to fail such that it needs a bit of manual help on release. Maybe that's why replaced ?

Not cheap I know !

Gold said:

I’ll be the stick in the mud. I don’t like KK connectors. Any connector that moves around makes me really nervous. When things break 99%  of the time it’s a connection.

I just had to break out my stash and crimp tool to connect to some Mean Well PSU’s. If it was mission critical I would have soldered to the connectors. This is for a bench power supply that won’t move so I’m using them.

I like the Phoenix terminal blocks. They come in the same pitches as KK so they fit.  For prototypes they are great because you have access to individual wires. When you use ferrules you can connect and disconnect as many times as you want. They are more expensive though.

Click to expand...

They are fine but you do have to make sure the crimp is good - airtight and gripping the insulation.

'Phoenix' type blocks are good too but the space needed for ferrules etc can be an issue in addition to the cost as you point out.
I do like the type where the wire goes straight in but connected by a lever action. Avoids screws being too loose / overtightened and 'tool free'. Space can be an issue as probably need to put wires in horizontally and cost  - but great for prototype / bench work.
KKs also give access to the individual wires - just need a finish tweezers or similar to flick the crimp tab.

80hinhiding said:

I've been crimping and soldering all my connectors, not wanting anything to come loose.

I've used some connectors from TE Connectivity as well.

Adam

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I've done that too - not having a proper crimp tool and not trusting the connection.
But soldering can introduce a problem of its own by introducing an inflexible  / brittle section where the wire meets the crimp. Bend the wire too far and it may simply fracture.And it's easy to apply too much solder which then interferes with inserting / removing the crimp.
One thing to bear in mind is to allow enough room to remove the connector by handling the housing and not the wires. The specified  'Pull Out Force' on the 2.54mm pitch parts are small - compare them to the same for 0.156" parts (Molex Product Info').

When I wrote loose I meant that there is wiggle room when the connector is mated with the header. It’s not a good locking connector. My crimps are fine.

I don’t consider flexing the locking tab on the pin to remove it from the connector easy access. It’s the opposite of that as you make the pins even less reliable than they already were.

Sometimes a Phoenix terminal block wormy work where a KK was but it’s pretty rare IME. I trust a screw terminal more than a spring clip.

I may have different standards but I consider one failure over many years one too many. Picture a unit full of KK connectors in an ancient heavily vibrating box truck going over cobblestone streets and pot holes all day for years. I expect the unit to work perfectly. Anything less I consider a design failure.

There are plenty of popular components for projects I wouldn’t use. I’m not impunining anyone’s character. Not everyone wants or needs bulletproof builds. I’d never use a lorlin switch or those blue and white plastic ones for example.  There is no reason for a casual user to buy an expensive switch.

80hinhiding said:

d

Martin did you get what you were looking for?

Adam

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Been side tracked mending my CNC Sherline mill drivers. A Chino driver blew up, so I'm resurrecting  my original A3977 pcb. .

But just to keep on topic, I'm using KK connector shells, with the wrong size crimps, that don't latch in properly ( plus gaffer tape)  Don't ask about using Dsub 9's for power!

Gold said:

I may have different standards but I consider one failure over many years one too many. Picture a unit full of KK connectors in an ancient heavily vibrating box truck going over cobblestone streets and pot holes all day for years. I expect the unit to work perfectly. Anything less I consider a design failure.

Click to expand...

Sounds like a terrible way to run a mobile facility 

But seriously folks...consideration of the environment a product is going to be used in is a proper engineering parameter.
Similarly you could insist on all connectors being gel packed to avoid ingress of moisture as used in automotive etc - but for a pro-audio product ? It would likely cause more issues than it solves (which would be zero unless you are operating in some strange environment - I suppose you could get flooded in a basement studio but then connectors wouldn't be your major problem). On a side note - that gel protection doesn't last indefinitely as it will dry out at some point.
Nothing is 100% reliable - sort of law of the Universe - but for highest reliability you'd need to be looking at more 'advanced' connector design / technology - Hypertac et al - used in Hi-Rel applications - Defence / Avionics etc. $£$£$£

The non fixed nature of the crimp in the housing (although pretty solid when mated to the header) actually helps with vibrations - the vibrational energy can be absorbed by the connection rather than cracking it.
I agree that the friction lock mechanism isn't particularly easy access but these connectors are intended for internal use - removal for inspection / service etc - not access for operational use so number of 'cycles' needs to be considered.

I am resurrecting this thread. I am working on some PCB's that have Molex KK headers installed already. I figured since I have a stock of KK pins and housings I'd use them for prototyping this build. The final build will use different PCBs (with Phoenix terminal blocks).

I am freshly reminded of how much I hate these things. I am using a generic ratchet crimp tool. I am using a headband magnifying glass to situate the wire in the pin. My problem is that about one out of every four pins won't lock into the housing. I can't see that anything is bent on the ones that won't lock in. No amount of bending or cajoling will get them to lock. I can't tell if the housings are pieces of sh*t or the pins are pieces of sh*t, or exactly how and where they lock.

It seems no matter how careful I am at getting the wire stripped to the correct length, seating it correctly in the pin and making sure the pin is as straight as possible in the crimp tool,  some pins just won't lock into the connector. The wire crimp on the pin looks good in all cases. The stripped wire is crimped by the second set of strain relief and doesn't protrude under the leaf spring of the pin. The rear strain relief is on the wire jacket. It is very frustrating after all wires are cut to length to have to cut a pin off and hope for the best. I can limp through this for a prototype but I couldn't imagine using these for an actual build.

I know most around here haven't sprung for the proper crimp tool at $750. I'm assuming with the proper tool things go more smoothly. I have an intellectual disconnect about how anyone could use this things. They are so touchy and unreliable. I'm pretty careful and have been doing this a while. I can't see how I can make these not suck with the generic crimp tool.

@Gold. There must be something wrong with your technique. I have just finished building a mixer with hundreds of KK crimps in it. Not once did I have a crimp refuse to lock. I have not found it necessary to get an exact strip length for a successful crimp. Doing it by eye is good enough. What is important is getting the wire the right distance inside the crimp and I do this by gripping the wire about a quarter of an inch from the end and then pushing it into  the ratchet crimper until my finger touches its side. It is also important to get the crimps in the right way up in the tool. What is very important is to use the right gauge wire.

Cheers

Ian

I’m not having problems with the wire making contact with the pin. Only having the pin lock in the housing . 

I load the pin from the rear of the tool so the locking tab on the underside of the connector is outside the crimp area. I make sure the pin isn’t twisted but vertical  in the tool. 

The crimps look correct to me. Bare stripped wire under the second crimp. Jacketed wire under the first crimp. The crimps are good in that respect.  I can tug on the wire and pin and they don’t come apart. Contact is good.

Something must be getting bent on the pin sometimes or something is bad in the housings I have. I have noticed that if a pin feels like it is on locking and I pull on it to test before it locks then it’s toast. It will never lock.

By what mechanism does the pin lock in place? Bending the tab on the underside of the pin out doesn’t help. Neither does opening up the leaf spring.  What happens when the wire gauge is wrong?