Molex crimp tool

Well, I've been crimping my SL .1" pins with a pair of pliers, and it really does work, but it is a pain in the ass... I'm ordering a few extra things from Mouser, and I was thumbing through checking out the crimp tools. I have never bought one because they are CRAZY expensive, $170 for the SL tool. However, Molex makes a "universal" crimp tool that seems like it is supposed to work on many of their pins, including the SL series. Why the hell would they make ten model-number-specific versions for a couple hundred bucks a piece when you can get a "univeral" for less than 40 bucks?? Is the universal gonna be a waste of money?

thanks,
andrew

I used to be a Molex rep down here in another life, so I know a little about this.

The tools made for specific terminals are ratchet types, with jaws tooled for the specific terminal, usually available in a couple of variations to suit different gauge wire. They are (or were a few years ago anyway) great quality tools. Spare jaws were available as replacement parts, and the ratchet mechanism was heavy duty. These are designed for low run jobs on production lines. There are also holders available for the tools to assist operators.

The universal tool is designed for prototyping/repair work. It is a plain design with jaws that will crimp various types of terminal. I always recommended it for engineering design work as it could do so much, for such little cost. It will not do really large or really small gauge wire crimps.

Just check with a Molex rep, or look in the catalogue to make sure that it will crimp the particular terminal you are using. From memory (never a reliable source) it would do all of the .1" terminals, but check to be safe.

A good crimp is a lot like a solder joint in that it must be done correctly or you will have problems like resistance and reduced carrying capacity. The expensive tools make this easier to achieve this reliably and with repeatability. This is crucial on production lines with different operators, but not as critical in R&D where the designer can check the workmanship himself/herself.

I bought a crimper for £8 - does my molex stuff no problem
2 sizes based on wire gauges

I always solder the small crimp connectors, and then apply a squeeze from a plier. Had many problems with elco crimp contacts in the old days.

My £8 tool was actually £14 - this one ....
Cheap Crimper for Molex

[quote author="gyraf"]I always solder the small crimp connectors, and then apply a squeeze from a plier. Had many problems with elco crimp contacts in the old days.[/quote]

I do the same thing, I never found crimp tools to work very well.

I think I read that if you solder multi-thread wires you are in fact heading for trouble as you are making the multi thread a single thread wire and thus you are laying trouble in store with breakages..

Fact or Fiction?

In theory it may well be so, but in practice soldering has presented the fewest problems by far - at least for me..

Yep,

Years ago I worked for a medical electronics company, and we had to solder every crimp terminal- it was the accepted method for increased reliabilty.

Mark

So which crimp pins and housings are you guys using? I've been using these AMP connectors using a T-handle punchdown tool that drives me nuts...I think I'd rather do the crimp/solder thing.

And here I thought I was the only obsessive person who soldered a crimp connection. I feel better now.

I think I am using 0.1" molex type connectors and housings...
But I find they don't crimp with very fine hook up wire...
(the crimp housings just fall off)

hey guys, check out this relevation at the seventh circle forums. the molex solution sucks compared to these connectors.

http://seventhcirclestudios.com/SCA/phpBB/viewtopic.php?t=305

my molexes were very ugly looking and time consuming to deal with.

i assembled these new connectors with a small flathead screwdriver.

Yea,

I've had experience with those IDC (Insulation Displacement Connectors) terminals. They're fast and efficient to install, but I did have some reliability problems on a few units. They are also quite fussy as to what cable you use, and without the "solder in" option of the Molex style connectors, it's difficult to guarantee an absolute 100% connection everytime. At least with the crimp 'n solder you can visually inspect the contact!

If you can get a good combination of connector and cable, I'm sure they're very practical.

Oh, and you can fab a punch tool from a screwdriver- just cut slots in the head!

Mark

i don't remember the gauge (its there in the SCA forum post) but the wire i used was just standard wire from radio shack. i had no problems with assembly or reliability.

It may have just been the combination of the connectors and wire type we were using. We just had a few problems with it!

Looks great for power distribution though, because you can install the connector as a "tap" on a continuous piece of wire.

:thumb:

Mark

Nice tips folks, I think I'm gonna stick to my plier crimping, with the addition of a bit of solder... I got me a used 'scope on ebay last night, and if there is no need to spend more money today, my bank will be happy!

andrew

IDC (Insulation Displacement Connectors) were developed to provide a QUICKER way to terminate than crimping. Many previous posts refer to the prsctice of crimping and soldering to achieve best electrical conductivity. If you count yourself in this group I would recommend avoiding IDC.

BTW, all the connector manufacturers make all the different types. Molex and AMP (now TYCO) are the two biggest connector manufacturers and both have what are referred to here as 'Molex' and 'AMP' connectors. Correct nomenclature is crimp pins or IDC (or IDT) style termination.

Look closely at an IDC connector. The metal device to terminate the wires is captive in the connector housing. You place your wire on the plastic holder above the terminator and use a special tool to push the wire into the terminator. The insulation of the wire is 'displaced' and connection made. A better way to describe this last action is that the termination is cut by the terminator which then contacts the wire.

If I had a good pic I'd show this, but bear with my description. IF the wire gauge AND the insulation gauge (that is, the diameter of the stranded or solid conductor and the diameter of the insulation) EXACTLY matches the size of the wire holder and the terminator, the contact/cutter on the connector should touch the strands of wire without cutting any strands. You are probably seeing the flaw in this style of termination. If you do not match wire gauge and connector precisely, or use the incorrect tool, or terminate slightly crooked, you risk cutting strands of wire, which reduces the effectiveness of the termination.

IDC is great on non-critical connections, certainly not power, where there are a LOT of connections to make. IT is designed for high rate production assembly and is simply not as reliable as crimping. And there is no way it is going to match criimping and soldering. Nothing will.

With the crimp-type connectors, are you supposed to strip the wire first or let the pin cut through the insulation?

I always stripped the wire when doing elcos but I'm not sure if it's supposed to be done on molex-type pins.

Yep, for crimp connectors, strip the wire. (IDC cionnectors alleviate the need to strip the wire, thus the applied cost saving in manufacture - that is how they were invented.) The crimp pin has two crimps, one for the conductors and one for the insulation. They are different sizes, thus the importance of matching the correct pin to the type and gauge of wire used. Connector catalogues should give you strip lengths for the different gauges and types of crimp connectors.

Stripping is also a critical process to avoid nicking the conductors, which could cause them to break later. If you strip and a few stands of conductor come off, you should really cut the wire at that point and strip again. Using good strippers is important. I've seen experienced people using all sorts of weird things to strip accuately, but that requires a great deal of experience. Mortals like me always use a quality stripper, carefully.