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  • Author Author: mcb1
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Meter Lead - JW special probes

mcb1

Some time ago made contact with me and wanted to send me some of his meter probes.

He's been keeping the community up to date as he makes changes to the original concept.

Shop Tips -  Intrusive Meter Probe

 

 

For anyone that hasn't followed John's work, his background is in dentistry equipment repair, and this has been the source of his inspiration for this product.

John Wiltrout's Blog

 

As the blogs testify, John is very practical and has applied this to solving many of the problems faced in his life.

 

 

Good connection

Anyone that uses multimeters regularily will tell you that getting a good connection to the device under test is essential.

More importantly a poor connection can steer you along the wrong repair path, which can cost money and time.

 

One day john was faced with just this problem and his solution was to use a dental burr bit on the end of the lead.

This would break through the coating and allow a good connection.

 

 

Special meter probes are available from manufacturers. I haven't priced them but the one annoying thing is you need to change the lead.

I have a couple of Keysight meters, and they get around this by having interchangable ends on the leads.

I haven't looked to see if Keysight do make a special sharp probe point, but I have seen others.

They are popular in automotive uses where they can pierce the insulation of the wires, but obviously they are dangerous due to the sharp nature required.

 

Johns solution won't pierce wire insulation, but overcomes the safety aspect by providing a flat end with multiple sharp parts that can bite through the thin coatings found on most circuit boards, .

As you can imagine they are not some cheap piece of metal with a token gesture of hardening, they are designed for digging holes into teeth, so the copper and aluminum we encounter is like butter in comparison.

 

In typical fashion John's latest iteration is designed these to simply slip over the end of the existing meter lead ends which means they are a universal fit.

 

image

 

Good meter leads are designed to protect the user from dangerous voltages. They include a wider section to stop fingers slipping down and making contact with the metal end.

The nature of this design makes them difficult to use one handed, and I can only imagine what happens when hand dexterity becomes an issue.

 

To give you an example of how useful these are, I tried measuring a resistor while it was sitting on the bench.

Modern probes have a reduced diameter near the end, and you can try angling the probe to utilise this to make contact, but if you tried this while it was in circuit, it wouldn't work.

Johns probes simply slip onto the end of the probes, and the task is not only possible, but the pressure required is significantly reduced as well.

It becomes so easy that it can be done one handed without much effort at all.

 

image

This shows you why.

 

 

 

Probe Slipping

Slipping is a cause of many electrical accidents. You're trying to balance a meter, put one meter probe onto one connection and then stick the other meter probe onto another point in the electrical switchboard.

In many cases there is a slip somewhere and with careful thought it won't be you making contact with a dangerous voltage.

Sometimes you get away from a shock, but your hand makes contact with the metal edge or some other surface, and you have an injury, bruise or other physical injury, and to top it off you drop the meter.

The non slip benefits of these can be considered a safety device, but if you're also dropping meters, then it can be a cost saving as well.

 

My next tests involve 'lending' them to some of the other teams at work, and seeing what they think.

They are already trying to borrow my Keysight Insulation Resistance Tester, and I'm happy to lend it out, but it comes attached to me so I get it back.  image

Keysight U1461A Insulation Resistance Tester - Review

 

 

 

Conclusions

So by now you will have guessed that I'm sold on these special probes.\

These are a prototype using off the shelf components, and assembled into a working product.

There are limitations on the abuse they can take from sideways pressure, but once they become a manufactured item, this will not be a factor.

 

I hope the ability to change ends can be incorporated, but the costing may be that this is not required.

Whatever the final product, I'm sure that meter manufacturers will be scrambling to offer it in their range, and it would be nice to think they reward John for using his concept.

 

 

 

Just remember you saw it here first at element14 community.

 

Thanks for thinking of me John.

Mark

Parents

  • Hi Mark,

     

         Just one clarification. The actual tips are friction fit into the adapter. You may need to grab the tip with a piece of rubber so it doesn't slip through your fingers but they will pull out to the front and they can be replaced with similar dental burs. I have found the best size is the USA number 34 or the European number HM-2 -008.

     

    John

  • in reply to jw0752

    You may need to grab the tip with a piece of rubber so it doesn't slip through your fingers

    That sounds painful given the sharp edges.

     

    So can I ask what does the actual gripping of the shaft then?

  • in reply to mcb1

    Hi Mark,

     

    When the drill is used in a dental highspeed handpiece (drill) it is held in the turbine by a jacobs style chuck, albeit a small one. I use a chuck from a particular handpiece and over compress it so it acts like three fingers holding the tip. Here is a picture of the chuck I am using:

     

    image

     

    Of the parts that I currently assemble to make the probe tip adapters this is the most expensive. I am sure a manufacturer will be able to make something similar that is less expensive but I do not have the micro machining capability in my basement shop.

     

    With respect to pulling the tip out of the adapter I usually use a small wire cutter and catch the tip just behind the head to pull it out. The shank is too hard, smooth, and tapered to be able to use a pliers to pull out and the tip. The pliers would just slip and damage the hard but brittle carbide tip.  Here is a picture. Just hold the cutter barely tight enough to keep it from slipping past the head of the tip. Most of my tips are actually loose enough to pull out with ones fingers but unfortunately I haven't been able to control the exact retention and so there are some where the cutter pulling technique may be necessary.

     

    image

     

    I thought I sent you a couple extra tips?

     

    John

  • in reply to jw0752

    I've got a set of John's lovely probes as well and I find them absolutely brilliant - best probe I've ever used.

     

    I looked into making my own and I solved the dental probe socket issue with these standard connector parts from Farnell: 3652051

     

     

    RC16M23K - Circular Connector Contact, Machined, Trim Trio Series, Socket, Crimp, 16 AWG, 20 AWG 

     

      SOURIAU RC16M23K 

     

     

      Add to compare 

     

    Image is for illustrative purposes only. Please refer to product description.

     

    Manufacturer: 

    SOURIAU 

     

     

    Manufacturer Part No:  RC16M23K

     

     

    Order Code:  3652051

     

     

    Product Range

      

    Trim Trio Series

     

    These are £0.87 each but you need to buy 25 in a packet - the grip the probe tips really well. I'm still looking for a nice and cheap socket for the standard meter probe - so far I haven't found a 2mm socket with spring leaves in it.

     

    Just for the record, I think the Wiltrouts are the best meter probes ever - by a long distance.

     

    MK

  • in reply to jw0752

    John

    You did send some tips thanks very much for those.

     

    I was curious what the retention mechanism was, and obviously it forms part of the electrical circuit.

    I did read your post and wondered if they were all the same.

     

    I am sure a manufacturer will be able to make something similar that is less expensive

    I agree and hope that they reward you for your idea.

     

     

    Thanls for sharing

    Mark

Comment
  • in reply to jw0752

    John

    You did send some tips thanks very much for those.

     

    I was curious what the retention mechanism was, and obviously it forms part of the electrical circuit.

    I did read your post and wondered if they were all the same.

     

    I am sure a manufacturer will be able to make something similar that is less expensive

    I agree and hope that they reward you for your idea.

     

     

    Thanls for sharing

    Mark

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