Masterclass - Alligator Clip selection guide for 2mm tip of multimeter probe

[Kiriakos GR]

This time we do not examine an Alligator Clip, or other add-on fine needle accessories about electrical properties and best conductivity.

They are two mechanical ways at attaching one accessory over one 2mm tip of DMM probe.

1) The accessory this has an internal reversed spring barrel, most quality alligator clips are made that way.
This hidden reversed  spring barrel, this becomes the contact point with your test probe.
Advantage: There is no damage over the nickel or gold plating over your test leads.

2) This is the bolt-on type.
The accessory ( alligator clip or other), this does not touch this 2mm barrel tip, as it will attached due a bolt connection.   

At our times, and at unbranded accessories, there is a ridicules product design of alligator clip.
They have press-fit the end point of the alligator clip, this now accepting a 2mm round pin.
This useless design, hides two risks, it will damage 2mm tip plating, it will lose tension force after few times of use.
And if you are using an expensive pair of test leads, this is the best way killing it.

History facts.
All branded 60mm length of Alligator Clip with rubber boot, they are made in Taiwan.
Originally the Alligator Clip this is designed to accept 4mm male banana plug.
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Assembly
Single reversed spring barrel this is inserted within the 4mm hole.
Reversed spring barrel this terminates to an flat end point, flat tab, this gets electrically welded (spot welding) over the nickel plated clip.
After this spring barrel insertion and spot welding, the two Alligator Clip jaws will be connected together due a master pin.

Conclusion
Even at the design of dedicated Alligator Clip for 2mm tip barrel connection, there is portion of engineering, and use of special formed metallic part.
A bit of cleaning and lubrication, over this reversed spring barrel, it will extend it life.
Use a bit of contact spray with oil over the 2mm tip barrel (probe), then insert the tip in to the alligator clip barrel.
   
   

[Kiriakos GR]

What ever shines this is no Gold .... wise saying or advice

This is yours rare opportunity, so to see of how one reversed spring barrel looks like.

This appears as gold plated steel, but it is actually brass plated steel.
For a few minutes I thought that I discovered the perfect 2mm short for gold plated test leads....
But the HIOKI RM3542A, this told me that I am a fool.   

From the narrow point of barrel No1 up to the narrow point of barrel No2,  they are 2.3 mOhm of resistance, that is very high if this was Gold-plating. 

Realistic assessment.
This is considered as best in class sort for handheld DMM, by using Zero button math function, the HH DMM it will happily measure from 0.3 Ohm and higher.
But I am currently seeking for better than that performance.
And this translates, that I have more road ahead so to get at my own goal.   
 

[Andrew-88]

Miniature level mechanical innovation   

Thanks mate !