[GreenKeys] Molex Connectors and pins

[Lee Mushel]

Keith,

What a wonderful contribution to the "art."   And I have printed your 
comments.   I will say that with the exception of the "telephone" type 
connectors so popular these days and for which I did buy a "proper" tool I 
belong to the "solder the dumb thing" school.   If I can't solder it I will 
get out the drill and file and a different connector will to in!

73

Lee   K9WRU
----- Original Message ----- 
From: "Keith Mc" <acti at provide.net>
To: <k9tty at dls.net>
Cc: <Greenkeys at mailman.qth.net>
Sent: Wednesday, November 09, 2011 1:23 PM
Subject: Re: [GreenKeys] Molex Connectors and pins


> [it sounds like you've had some experience with this...]
>
> Uh... you could say that. <grin> I've been doing crimping for many decades
> now, as both a tech and an Engineer. I also teach it every year at various
> high schools in my area, to my HS robotics teams' Electrical Group 
> members.
> (...Trust me, I've ruined my fair share of pins over the years, to finally
> master the finer points of doing it. :-)
>
> DR HOUSE <k9tty at ...> wrote:
>> I agree,  It does take some talent to get them installed well.
>> It helps a lot to have the correct tools.  I do not trust myself to crimp
>> them properly so I carefully fold the insulation tabs and solder the 
>> pins.
>> I have heard other folks giving up on the Molex connectors completely and
>> changing them out to RCA phono and WECo 310 TRS jacks and 303 TS Jacks.
>> However you must not leave any open holes, less the mice get inside...
>> In most cases patience is a virtue.
>
> Interesting.  FYI, studies have shown that *proper* crimping can actually
> form a BETTER and more reliable connections than soldering.  Just like 
> with
> Wire-Wrapping, during crimping compression you can actually achieve a
> microscopic metal-to-metal weld.
>
> The REAL trick is getting ahold of a DECENT crimping tool of the RIGHT 
> type,
> and understanding the concept of (and how to execute) the "Tulip Crimp".
>
> NEVER, EVER use the "oval" shaped crimping tools, like you often see
> sold at auto supply stores.  They make absolutely HORRIBLE crimps.
> (IMHO, they are why many people give up on crimping...).
>
> What you want is to invest in a DECENT, "heart shaped" Tulip Crimping 
> tool.
>
> THIS one handles most of the electronic pin crimp sizes we'd be interested 
> in:
> ... http://search.digikey.com/us/en/products/63811-1000/WM9999-ND/243789
> ... http://media.digikey.com/photos/Molex/63811-1000.jpg
>
> It's made by GC/Waldom/Molex, and is good for virtually any basic 
> electronic crimp.
> The Waldom WM9999 is the tool that *I* use for most of my 14-30ga work.
> As you can see from the pic, for $35 you get a tool with *12* different
> sized Tulip Die (heart shaped) positions for crimping.
>
> Automotive and other bigger, power wiring are MUCH different animals,
> and require a different kind of tool altogether.  They should be done with 
> a
> Dimple-Style tool, a third type of tool (which we can discuss later, if 
> you wish...)
>
> Next, you have to understand the concept of a Tulip Crimp.
>
> Most crimp pins are "swaged".  IOW, stamped from flat plate stock,
> then folded up origami-style, by again stamping in a series of dies.
>
> The pin will have TWO U-shaped sections.
> ... The one closest to the pin tip is for the bare wire, to connect 
> electrically to the pin.
> ... The one at the back end accepts the INSULATED wire, as a Strain 
> Relief.
> Attaching this pin will require TWO crimps, using DIFFERENT sizes of die 
> on your tool.
>
> Strip the wire according to the pin's specs.  You will expose JUST enough
> of the bare wire so when the wire is positioned in the pin for the strain
> relief to grab the insulated end, the bare wire will just BARELY 
> overextend
> beyond the wire crimping zone.  Too much bare wire and the strain
> relief won't work, or strands could flare out and touch other things.
> Too little wire exposed, and you may catch insulation in the wiring
> crimp while trying to do the first crimp, or not have enough bare wire to 
> grab.
>
> Also make sure the end is CLEAN and shiny.  If too oxidized, clip off the
> end of the wire and try again.  Most of the time oxidation is limited to 
> the
> first fraction of an inch of long exposed wire on the reel.  If it is 
> still
> oxidized after cutting an inch up, use a foldover of very fine sandpaper
> to pinch-and-pull to "shine it up" a bit. This insures a good electrical 
> connection.
>
> We will start with the BARE wire crimp.
> After doing it correctly, we THEN do the STRAIN RELIEF crimp.
>
> In making a Tulip Crimp, ORIENTATION is essential.
> Start by placing the empty pin with its U in the "base side" of the Heart 
> Die.
> The two ends of the U are now facing the double curve of the other side of 
> the die.
>
> If the flare of the U is too wide to enter the outer edges of the other 
> side
> of the die (the "double curve" side), you may have to first squeeze the
> two sides of the U together slightly, to make them parallel.  You can do 
> this
> with either a pair of needle nose pliers, or it can be done with a gentle
> touch by placing the U facing sideways on the "two flats" portion of
> the tool, and giving it a GENTLE squeeze, until they JUST become parallel.
>
> Now, with the U of the electrical crimp in the base of the Heart, squeeze
> JUST enough to grasp and hold the pin firmly in place (NOT crimping!),
> so you can insert the wire.  IMPORTANT:  The back end of the electrical
> crimp zone should now be FLUSH with the surface edge of the tool!
>
> IF everything is right, you can now insert the prepared wire, and the
> insulation will "bottom out" just shy of the electrical crimp zone.
>
> (Execute the BARE wire crimp)  SQUEEZE HARD.... Pause... Release...
>
> Looking from the end, you should now have a HEART SHAPED CRIMP.
> The two ends of the U should have followed  the curves of the double 
> curve,
> causing them to CURL BACK on itself.  This causes the two ends to turn
> 180 degrees, and jam themselves back INTO the wire bundle, while
> the die holds the sides together to keep them from expanding.
>
> The top now looks like "two bumps", just like a Tulip Flower (hence the 
> name).
> If done correctly, you should now be able to tug on the wire slightly,
> and it won't come out.
>
> If this didn't work (eg the wire is still loose), you may have used
> the wrong die for the selected wire size.  You can sometimes SAVE
> this by CAREFULLY moving the entire assembly to another die
> (typically one step smaller), and squeezing again.  Again, BEFORE
> squeezing make sure your orientation is the same as before!
>
> Next, we do the Strain Relief Crimp, with a slightly LARGER die.
>
> Depending on the thickness of the insulation, move one or two steps
> LARGER in die size.  Repeat the above directions as to orientation
> in the tool.
>
> My Trick - Since adjacent sized dies on the tool are alternating in
> orientation, "The Move" consists of quickly FLIPPING the tool
> between the two crimps.  Spin-flip the tool 180 degrees in your
> squeezing hand  while holding the wire&pin still in the other hand.
> Done correctly, it allows you to "crimp, flip, crimp" in succession. 
> <grin>
>
> HOWEVER, this time, for the strain relief crimp we will squeeze LIGHTLY.
> The point is not to PIERCE it, but only to CURL the U back to wrap and
> HUG the wire to add support.   In fact, if you try to use the same
> die as before (or squeeze too hard),  you WILL fracture, or even
> shear off the wire entirely!
>
> Therefore DIE SIZE IS CRITICAL here.  It is better to err on the
> LARGE size while getting used to executing the Strain Relief Crimp,
> because you can always step back down in size and repeat it,
> if necessary.
>
> On some pins, the strain relief U is way too long for the diameter
> of the insulation.  If this is true,  you can shift this to an Overwrap
> Crimp by using needle nose pliers to fold the two U legs first,
> and THEN crimp it.  This forces the two sides to slide around each
> other, and keeps it from forming a High-U Tulip with an air gap
> under the arches (which doesn't hold against strain very well).
>
> If both crimps were done right, you are now left with a correctly
> crimped AND strain relieved wire, ready to insert into the housing.
> (<snoopy dance> Yea!)
>
> There is one exception I've found...  Trying to crimp a 22gauge wire onto
> a pin to fit 0.100" center housings.   You sometimes have to do a THIRD,
> VERY light crimp on the strain relief crimp with the next size smaller 
> die,
> to just --slightly-- compress the insulation in order to get it to fit 
> into
> the housings.
>
> One more thing... On many Molex pins, the original swage-forming
> process may leave the two tabs that keep it retained in the housing
> too close to the pin's surface to properly do their job of grabbing the 
> housing.
> So, to fix that I always make sure I GENTLY fan them out just a bit with
> a dental tool, before attempting to insert them into the housing.
> This makes sure both tabs will engage properly.
> But be VERY careful!! More than once I've had a weak tab break off in
> my hand by trying to flare them too far, or with too much force.
> (...mumble grumble...)
>
> Bottom line:  Proper crimping is a function of the RIGHT kind of tool
> (tulip), proper pin and wire prep, using the RIGHT sized dies for the pin
> and wire combo, AND using the RIGHT squeezing touch...
> All of this experience comes with a LOT of practice (and ruined pins... 
> ;-).
> So again, please make sure you get a few extra pins in your order...
>
> Does this all make sense?
>
> - Keith Mc.
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