Inverted Alligator Clips?

[hal9001]

Are there test clips that work opposite direction of alligator clips? I want the clips to compress whilst pressed and open whilst let go. I want to measure inside different diameter holes using spring force to hold the clip.

Cheers

[donlisms]

I think crocodile clips are sprung outward, with a sort of crossover action.  You would have to experiment with different modifications to remove the parts you don't want, and shape the jaws.  This only works if you have a file and pliers and don't mind getting your hands a little dirty!  :-)

[jpanhalt]

Why not use a spring loaded, inexpensive hole gauge (attachment)?  They come in quite small sizes.  The ends are domed so they self-center a little, but not as well as much more expensive 3-tab hole gauges.

[CaptDon]

How on earth does an inverted alligator clip help you measure an I.D.? One would think you would use standard methods like inside calipers or any standard accurate measuring means.

[donlisms]

I don't think OP wants to measure the ID; this is an electronics forum, and I think he wants to make electrical measurements.  Inside holes.  Of various sizes.

Thus... something vaguely like an alligator clip that works backwards; tension outward, gripping the inner wall. 

[PCB.Wiz]

Are there test clips that work opposite direction of alligator clips? I want the clips to compress whilst pressed and open whilst let go. I want to measure inside different diameter holes using spring force to hold the clip.

That's non standard, but you could modify existing clips ?
You could reverse the spring, or you could solder on extended fingers, bent & crossed over so that when they are in the hole, they prevent the clip fully closing
There are also barrel connectors and terminals, that are designed to go into holes, that might work too.

What sized holes do you want to probe ?

[hal9001]

I don't think OP wants to measure the ID; this is an electronics forum, and I think he wants to make electrical measurements.  Inside holes.  Of various sizes.

Thus... something vaguely like an alligator clip that works backwards; tension outward, gripping the inner wall.

Thats precisely it!

Are there test clips that work opposite direction of alligator clips? I want the clips to compress whilst pressed and open whilst let go. I want to measure inside different diameter holes using spring force to hold the clip.

What sized holes do you want to probe ?

Inner diameter can be from 5mm to 10mm. They are hand drilled holes where the outside is coated with insulation so I have to take measurements inside of the holes.

It neednt be alligator clips, it was the first thing I thought of.

[PCB.Wiz]

Inner diameter can be from 5mm to 10mm. They are hand drilled holes where the outside is coated with insulation so I have to take measurements inside of the holes.
It neednt be alligator clips, it was the first thing I thought of.

They are sprung loaded and common, so not a bad place to start.
Aliexpress have banana/bullet plugs up to 2.5-8mm
For larger holes you could use the rear end of a bare alligator clip, extended to fit the hole.

[NiHaoMike]

Would be easy to make one by bending a strip of springy metal into a U shape.

[MLXXXp]

It neednt be alligator clips, it was the first thing I thought of.

How about cutting off the head and point of a safety pin, bending it to shape if necessary, and soldering a wire to it?

[TimFox]

I think crocodile clips are sprung outward, with a sort of crossover action.  You would have to experiment with different modifications to remove the parts you don't want, and shape the jaws.  This only works if you have a file and pliers and don't mind getting your hands a little dirty!  :-)

Real crocodile clips are sprung the same way as real alligator clips.
The difference is that the upper jaw of the crocodile clip goes within the edges of the lower jaw when closed.
See  https://www.muellerelectric.com/products/bu-85c
Since they were introduced by Mueller many years ago, other vendors have treated alligator and crocodile as synonyms, another incidence of obscuring useful differences between similar objects.

[Smokey]

What size holes are you talking about here? 

[notsob]

If you only need to check for specific size compliance, why not use some gauge pins for a go / no go test

[donlisms]

Real crocodile clips are sprung the same way as real alligator clips.

Hm.  I was thinking of something more like the Mueller BU-45, which I guess is not "real"!  :-)

[TimFox]

Real crocodile clips are sprung the same way as real alligator clips.

Hm.  I was thinking of something more like the Mueller BU-45, which I guess is not "real"!  :-)

The BU-45 is neither an alligator nor crocodile clip.
https://www.muellerelectric.com/products/bu-45

[donlisms]

Regardless, those are what I was thinking of.  I've heard them called crocodile clips since most folks here were born!  Cut me a little slack, eh?  Just trying to help. 

[TimFox]

In my youth, which predates most of the members here, they were often called “battery clips”.
My pet peeve is treating “alligator clip” and “crocodile clip” as synonyms, when the Mueller catalog shows the clear difference.
Citing the Mueller catalog page is my way of helping.
Mueller invented alligator and crocodile clips in 1908, which is before my time.

[mzzj]

I can imagine these would be really handy in some situations but it seems like non-existent product or it goes with so exotic name that it doesn't show up with regular google-fu.

Some alligator clamps look like they would be reasonably easy to modify with dremel, soldering iron and bunch of metal pieces but I get that ready-made product would be nice if you need more than 2.

[rdl]

Probably not exactly what you want, but they do exist.

https://modelpaintsol.com/model-paint/reverse-alligator-clips-sturdy-bamboo-sticks-painting

[Dundarave]

If you’re just looking for something quick and dirty, the steel wire handles of steel, black, paper binder clips can be removed from the spring clamp itself, and they spring “outward”, as it were, and have a convenient loop to fasten a probe.

They come in sizes from 3 inches down to 1/2”, and are available at pretty much any stationery store.

You could remove the handle from the clip, compress the ends, put it down the hole, and the legs will bear against the side of the hole.  Cheap and quick.

[radar_macgyver]

For small diameter holes, you could use a Keystone test point or similar:
https://www.keyelco.com/category.cfm/Test-Points-Tips-Probes-Clips/Test-Points-color-keyed-Thru-Hole-Mount/id/521

Looking at how the 'without base' ones are made, just bend a piece of phosphor bronze wire into a U shape and you're done.