How to Make Connections at Pier 9




Introduction: How to Make Connections at Pier 9

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Want to meet people in the electronics lab but have no idea about what to talk about? Make some connections! Ask them about a project that failed in the field, chances are it's because of a loose connection.

We've all been there with projects that don't preform at a crucial moment. Nothing kills a project quicker than a janky solder joint or a lose wire. It's time to deal with those rats nests and make solid connections with the amazing connections drawer put together by shop staff Coby.

Thanks to Dot for the video help.

Step 1: Connection Resources Available

Molex Microfit 3.0

General Purpose Removable Wire-Wire/Board rated to 3A

Spade Terminals

For Power to screw terminals or large gauge applications

Ring Terminals

For Grounding your projects and making them less likely to zap your user

Insulated Crimp Sleeves

For when you screw up and need to add permanint wire to wire

Step 2: Molex MicroFit 3.0 Overview

Molex Microfit 3 is an extremely durable reliable and high current modular cabling system for wire to wire and board to wire connections. It's widely used in prototyping and even production applications, you can find it in the Type A Machines Series 1 3D printer as well as the Autodesk Ember 3D printer.

It consists of some standard modular components:

Male crimps

Molex part #43031-0001

Female crimps

Molex part #43030-0001

Male housings and female housings in everything from a 1x2 up to at least 2x6

For basic 2 wire connections the drawer is stocked with 2x1s:

Housing Plug

Molex part #43640-0201

Housing Receptical

Molex part #43645-0200

The crimps crimp onto the end of your stripped wire with the special crimping tool.

Molex part #63819-0000

The Male crimp goes into the female housing.

The Female crimp goes into the mail housing.

Once the crimps are in the housing they have positive locking and mate nicely with their pair to form an easily removable solder free connection!

Step 3: Molex MicroFit 3.0 Stripping

The Mircofits are precise, they are incredibly reliable when they are properly assembled, but if not they can fail unexpectedly. Good assembly starts with the stripping.

Cut your wire to the approximate length you need, leave an additional inch or so for stripping.

Inset the end of your wire into the stripping tool. Make sure the end hits the red guide, its easier to strip too much wire then cut it back then to strip not enough. Squeeze the tool and the jaws will engage and strip the wire. If the wire falls out without stripping just put it back in and go more slowly.

Once you've stripped your wire use the flush cutters to cut back the exposed copper core to about 1.5mm from the end of the insulation. This is all you need to make a good connection. If too much is exposed the connection will be weak, if too little then the crimp won't fit.

Step 4: Wire to Crimp

Select the crimp you will be using.

You will see the crimp has 2 sets of jaws. They should be open in the pre-crimped (new) postion.

The jaws on the outside of the crimp are for gripping the insulation, the inner jaws grip only the copper core of the stripped wire.

Place the stripped wire into the crimp so that the end of the insulation is just outside the inner jaws. This is the correct position. If you stripped the wire to the correct distance it will soft of click in and will not be able to be inserted any further.

Step 5: Inserting the Crimp in the Tool

Now grab the Molex crimp tool. This is an amazingly precise piece of hardware. It does one thing and it does it perfectly. Grab the tool with your right hand. Squeeze the handle to see how it crimps and releases.

When it's open press the big red knob on the back and the sockets will slide forward into the loading position.

Slide the crimp into the red plastic holder, the jaws should be point up or away from the handles of the crimper, select the hole that most closely matches the gauge of wire you are using. Slide it in so the end with the wire points out. The crimp should go about 2/3s of the way in the stop. When it stops release the loading button and the crimp will slide back with the red plastic holder.

Place the wire into the crimp jaws, double check that the insulation jaws are grabbing the insulation and the wire jaws are only on the wire.

Step 6: Crimping

Grab the handles and close the crimper slowly. As you ratchet down you can look through the side of the tool to see if the wire moves. It will ratchet closed then release. Pull the wire and the crimp will come out of the housing.

Step 7: A Successful Crimp!

It can take a couple tries to get it perfect but once it does the crimp should solidly attached to both the wire core and the insulation.

You can see an example of a correctly crimped part here.

Step 8: Crimp to Housing

Now it's time to get the housings. There is a male and a female of these as well. The male crimp goes to the female housing and vice versa.

The housing have a top and a bottom as well as left and right positions. The crimps will only slide easily in if they are in the correct orientation vertically. If the crimp doesn't go in then flip it upside down and try again.

Step 9: Opposite Gender

Now that you have completed a crimp from one gender go for it with the other, it's the exact same process. Make sure you are inserting the crimp into the correct opposite housing.

Step 10: Completed Set

The housings are marked left and right to help with wire identification. The big '1' on the female housing matches up with the embossed line on the male crimp. This is important to keep your wire order correct.

A completed set consists of 2 male and 2 female crimping inside their matching housing.

There is an example in the connectors drawer. If assembled correctly the wires should not come out even with a strong tug and the connection should stay together.

If you squeeze the top and bottom of the connection the latch with open and it should easily slide apart.

And that's it for Molex! Happy crimping!

But what if you want to connect to a screw terminal on a power supply? There's a crimp for that!

Step 11: Spade, Ring, and Sleeve Crimping

Space Ring and Sleeve crimps are peppermint connectors. Unlike Molex connectors they cannot be easily undone.

They are typically used for power or grounding connections. Insulated sleeves are used for connecting wire to wire instead of soldering.

These crimps come in a variety of sizes, generally for each wire gauge size there is a variation in the size of the screw terminal as well.

Step 12: Tools and Parts

The tools for the terminal crimps are in the drawers next to the soldering stations.

You will need a special ratcheting crimp tool

The stripping tool

A flush cutter

and the crimps

Step 13: Stripping, Cutting, Tinning

Terminal crimps are much less finicky about stripped wire length than the molex crimps. You should strip about 1/4-1/2" of insulation then cut the stipped wire back to about 1/8" long. The crimp on these terminals holds onto both the insulation and the wire core at the same time.

If you are using a wire size that is too small for your crimp or you attempt to crimp and it fails you may be able to just tin the wire using a soldering iron then try again.

Step 14: Inserting the Wire

Insert the wire into the crimp end of the terminal, it should be coming out the side away from the terminal and you should just be able to see the copper core by looking down the barrel away from the terminal. Make sure the insulation and the core are inside the crimp.

Step 15: Crimping

Grab your ratching crimper, most crimps are color coded, match the crimp up with the slot in the crimper with the same color in this case red to red.

Step 16: Finished Crimp

And that's it!

This same process applies to the ring and spade terminals, the insulated sleeves are similar except you just put 1 wire in each side.

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    9 Discussions


    Reply 5 years ago on Introduction

    Hey Eric,

    The part numbers for all the connectors and molex components are now in step 2.


    Reply 5 years ago on Introduction

    Rad. It would be cool to let people know who can't afford the $300 crimper which of the 3rd party (<$40) tools work, e.g. or

    I have one of the Engineer tools but unfortunately not nearby to test with Microfit parts. They do work with Molex PicoBlade etc. Note to whoever - the cheaper tools work, you just to have check compatibility, but are not as nice as the official Molex tool...


    Reply 5 years ago on Introduction

    Honesty we've had nothing but bad experiences trying to use the cheaper crimp tools with the Molex crimps. The Sunpack, and Jameco tools that supposedly work, only crimp adequately about 70-80% of the time. They also seem to not be able to crimp the wire holding part correctly and lead to breaks in the field. I would really recommend going with the name brand tool, it's an investment in making good connections and will last years. A less expensive option might be this tool: but it's non-ratcheting so It would be possible to overcrimp


    5 years ago

    Yes, the 0.1" are the ones I am referring to. My crimper is more like this on.

    I'm lucky if I get 50% success rate.


    Reply 5 years ago on Introduction

    The Jameco one seems to be pretty solid, on the 0.1" crimps we are usually getting about 90% sucess rate. If you use the Jameco tool on the molex crimps, although it's possible to get it to work the success rate is about 70%


    5 years ago

    Any advise on dupont connectors? Please please please


    Reply 5 years ago on Introduction

    great idea johnip4, we need to get some of those, if I'm looking at the right thing they are the 0.1" generic connectors? They can go into breadboard headers and have wire to wire connections. We use those as well for lower profile connections. The great thing about those is they don't require the special tool. I recommend the Jameco Generic ratcheting crimp tool.