Cheap Alligator Clips for your Multi-Meter

Rigidity is good.

A friend of mine a while back bought me a multi-meter (thanks T-Bone!).  It’s a pretty darn good one too, but just like everyone else who uses a multimeter often, I found myself wanting a way to attach my leads to wires and have them STAY there.  Before I knew about places like SparkFun and Parts-Express, my shopping experiences told me that new leads were going to be too expensive for as often as I use them.  So it went that I just continued to pretend I was ambidextrous, or held the probes in my mouth (what? eww…) or otherwise just failed.  Until one day I had enough.  I just had to have some alligator clipped probes.  On a recent trip to Harbor Freight I had purchased a 6 pack of alligator clips for about a dollar for another project, and had four left over.  In my desperation I actually had wire cutters in hand with the jaws on my test lead about to cut… … …but I couldn’t do it.  I just couldn’t sacrifice my leads, even in my desperation.  So I sighed and tossed my pliers to the side and sulked.

Now sulking is when I do my best thinking.  You see, it is then that I throw all calculated and rational thought out the window and begin to fantasize about wild possibilities and ideas that usually involve too much money.  “Wouldn’t it be nice, ” I thought, “to just be able to have interchangeable probes on my  test leads?  Not have to change the whole lead, but simply put  on a new attachment, like with a vacuum cleaner?”  Then I had an epiphany.  I could crimp down the ends of the alligator clips enough to slide them on the probe tips! Yeah!

No.  After completely mutilating two alligator clips, I came to the realization that they were too big in the barrel, too cheap of metal to retain any kind of tension, and would not last.  There had to be another solution.  But what?  I shelved the idea until another day…

Then, on another project, ‘Making a Bench Power Supply out of a PC Power Supply’, I stumbled on my idea.  I was testing the output of the power supply, and again didn’t feel like holding my lead, so I jammed it into the pin on the Molex connector- and it stayed!  And it didn’t just stay, it stuck! So the Power Supply project got way-laid by the resurrection of this Alligator Clip project.

Here is what I did:

Find a ‘something’ with a male molex connector on it.  In this example it will be a cooling fan off a Pentium-II, maybe-  I don’t know where I get this stuff.

Sacrificial Fan

Sacrificial Fan

But the part I am interested in is the Male Molex connector.  It has the nice open pins as such:

Male Molex

Male Molex

In order to take the Molex connector apart, you will need a Molex pin removal tool.  Well, you don’t have to have one, but it really helps.  You can just use a needle, or jewelers screwdriver or something.  The tool looks like this:

Molex Tool

Molex Tool

The tool has two different sized ends, one for the female pins in the male connector, and one for the male pins in the female connectors.  I guess Molex connectors are bi-sexual?  Yeah.  So the end we need for the male connector/female pins is the larger end.

Da Big End

Da Big End

These tools are designed to slide over the pins and disengage the little retaining flanges that flare out and hold the pins in place.

Flanges Out

Wildly Flaring Flanges

And, uh, here is the tool being used…because, uh, yeah.

Tool in Use

Tool in Use

Once you have a pin out, it looks like this.

Pin out

Pin out.

Yay.  Now what do we do with it?  Well, I cut it off at about 2 inches, then I tinned the end of it to make it nice and solid and a little bit malleable so it would fit better on the screw.  I bent the tinned wire with some needle nose pliers into a hook, and torqued down the screw.  I made sure I ran the wire through the opening, and not just on the outside of the clip.  These screws could be tightened down a good bit, and hold VERY well.

Screw it.

Screw it.

Once the whole caboodle is assembled, you have to make it tight.  Molex connectors are made with a little bit of a gap where the two ends meet (see pic above).  Take your fingers, or a pair of pliers if you will, and squeeze the pin so that the ends of the metal touch.  This makes the connection tighter. I also pinched the little flanges inward into the barrel of the pin, such that they ‘locked’ into the little depression on my probe.

Flanges In

Flanges In

Little Indention in Probe

Little Indention in Probe

Attaching the alligator clip to the probe is as simple as sliding it on.  The little flanges help lock the probe in place, and the wire is stiff enough that they don’t flop around aimlessly.  Removal of the alligator clip is just as simple as pulling it off since the flanges lock onto the probe, but don’t “LOCK” onto the probe.  Hope that makes sense?

Putting it all together.

Putting it all together.

Rigidity is good.

Rigidity is good.

The clips on the probes hold exceptionally well.  How well?  There have been a few times my multimeter has fallen off the bench, and the probes did not release and took the project with them on the plummet to the floor.  Here is an example of the retaining strength of these:

Good Hold

Good Hold!

There is a pic of the probes and clips holding up my multimeter.  For that pic, I just held it up in front of my chair.  I wasn’t even ginger with it.  I was going to shoot a video of me bouncing the whole thing a little, but they couldn’t hold up to that, just to give you an idea of the release point.  The clips in question in this picture are more than 4 years old, and are in fact the first set I made.  They still hold today as well as they did when I made them, and I have not rebent the flanges in for a better hold, even for this picture!

All in all this has been one of the simplest and most beneficial tool mods I have ever done.  I guess you could say I got the most ‘mileage’ out of these.  When on the multimeter, they have no resistance and make very good connections.  I also just found out recently that they fit perfectly over 12 gauge solid wire.  The little flanges, again, help ‘bite’ into the soft copper.  This is wonderful for making impromptu and temporary jumpers and whatnot.  Another  small added little benefit is that with the Molex connectors you get the most common wire colors to choose from: Red, Yellow & Black.  This way you always can tell your + and – sides!

All done!

All done!

10 Responses to “Cheap Alligator Clips for your Multi-Meter”

  1. Jonathan says:

    I’m going to try this. Oh, and I have not heard of parts express so thanks!

  2. lamovr says:

    My “official” alligator clip adapters are AWOL, so I’m going to make some homebrew doodads using your technique. Thanks!

  3. cheitzig says:

    I had the same problem. Turns out someone else solved the problem too– RadioShack sells these “Insulated Alligator Clip Adapters”. See: http://www.radioshack.com/product/index.jsp?productId=206222

  4. Ill Master says:

    Genius!!! I happened to be shopping for probe clips, was VERY put off by the prices everywhere, and stumbled onto your site. Love the way it all came together, the black/red choices, the flanges snapping onto the tip grooves…pure inspired genius, and perfect timing for me!! Thanks for posting this, I’ll be making mine shortly as I have all these parts sitting right here!!

  5. Matt says:

    Good idea. I have about 10 of the free multimeters from HF and just sacrificed the set of leads that came from the meter that I turned into the voltmeter for my kids powerwheels. I cut them and soldered in barrel connectors and did a variety of clip sizes. Just look for the free multimeter coupons. The lead connectors work on my good multimeter just fine.

  6. Jeremy says:

    This is a great idea. I just bought some insulated alligator clips from a thrift store for 25 cents and the first thing that I thought of was how can I make these work for my multimeter? I thought of a few ways and then I found your site. I want to try this and I have all of the parts needed, but I have a couple of questions. First of all, what size screw did you use for this? Also, in the the finished pictures it looks like there are two pieces of wire attached to the molex connectors. Is that correct or are my eyes playing tricks on me? My question is why wouldn’t you just use the single wire that is already coming out of the molex connector to tin, hook and screw into the alligator clip?

  7. Depending on what you’re doing with them this could be very dangerous, your meter doesn’t look very safe either.
    I agree it would be nice to have exchangeable probes but for serious work outside of measuring DC voltage on 1.5 V breadboards you should consider getting a decent set of test leads.
    Probes should have a safety symbol of a third-party testing agency and CAT III/IV compliance.
    If you buy a mutlimeter that is safe you will already have a few different probes included, at least some alligator probes. But this sort of meters will cost you $50-$100 Dollar. The good thing is that you will not have any electrical hazards with them.

    • admin says:

      On my $400 Fluke at work, yes, I get only the top quality leads since I’m running down voltage on repeaters in 100W microwave towers.

      But at home doing small circuit DC type stuff, nothing more is needed.

      Thank you for commenting and supporting my Blog. Your profile links to a site that reviews multimeter stuff. Someone may find the information and products useful.

Leave a Reply