Video's of making the Ultimate Kelvin connection(major hacking of a Pomona clip)

[robrenz]

This is the first video of two that show my quest for the ultimate (IMO ) Kelvin connector system.  Sorry for the long length but I tried to keep it very concise while still showing all the techniques used.  I am not nearly as dynamic and entertaining as Dave so try to stay awake   This is very mechanically oriented but many forum members seem to like Dave's fixture related stuff so I hope you find this interesting as opposed to boring.

This first video covers the modification of a Pomona 5418 pincer clip into a Kelvin clip.  This clip is the basis of a system that will allow any combination of clip, probe, soldered-on wires, clamps, etc. to be used instantly. The second video will cover the making of all those attachments of the system.

[JuiceKing]

Great idea and fascinating video. I see you made a pile of these. Are you planning to make a business of this?

[robrenz]

If there is a lot of interest I would run another batch of them.  But as you can see they won't be cheap as there is a lot of work in them. I don't expect to get paid for the development and fixturing time I consider that playtime. I will post what I think they will sell for when I figure that out.

That is not my main purpose though. I just want to contribute to the forum in the areas I feel I have something worthwhile to post.

[JuiceKing]

Thanks for posting it. It's a world I know nothing about. My only other experience observing machine tools was at the Paul E. Garber Preservation, Restoration, and Storage Facility in Maryland, where the Smithsonian works on military aircraft restoration projects. This was many years ago, and I was a production assistant in a TV crew doing a documentary on the restoration of a WW2 Japanese airplane. They had some 30 gigantic warehouses full of aircraft and a small team of restoration experts that would take these planes apart down to the individual part, clean them up, and put them back together again...restored in flying condition. Parts that were missing or unusable were machined from scratch. After they put it all back together again, they would coat the finished work in some kind of preservative resin that would keep them from rusting but would ground them permanently. Like mummies, I thought. This was around 1989, I think, and they were working on the Enola Gay at the time, and many years later, I saw an announcement that they finally finished it. Needless to say, the guys who worked on these things thought they had the best jobs on the planet. Very cool.

Can't wait to see your kelvin probe and the ingenuity that goes into that.

Thanks again for sharing this.

[PedroDiogo]

I was delighted watching this video. I didn't even know that was possible to machine something so small with such precision, great work

Subscribed the channel also.

[almoehi]

Hi robrenz,

thank you for the very informative and fascinating video. Big thumbs up!!!

Cheers,
Armin

[DmitryL]

Great video, nice to watch!

But is there anything wrong with things like this: ?
http://www.dealextreme.com/p/test-clip-probes-for-lcr-meter-with-bnc-wires-pair-34214?item=8

And Open-Short-Load probes calibration  as well ?

[JackOfVA]

Great video, nice to watch!

But is there anything wrong with things like this: ?
http://www.dealextreme.com/p/test-clip-probes-for-lcr-meter-with-bnc-wires-pair-34214?item=8

And Open-Short-Load probes calibration  as well ?

I've bought a couple sets of these and find them acceptable considering the modest price. However, with extended use the RG-174 coax fatigue fails at the clip end. It's not difficult to repair the failure, however.
 

[digsys]

Holly snapping duck shit !! That is awesome work !! I'd have drilled and machined off MOST my fingers trying that !!
Put me down as a potential customer. Thank you for showing us what can be achieved.

[Chasm]

Very nice!

The machining work I've seen so far was much coarser.

[nanofrog]

Absolutely beautiful work IMHO. 

I'd dearly love to learn machining at that skill level. Huge Thumbs up!

[robrenz]

Thanks guys, I have lots more to come.

[IanB]

I think having an electronics workbench in your garage is one thing. But having a high precision machine shop in your garage is crazy!   

[M. András]

wow, nice tools and very good workmanship. you dont have problems with thigs you cant buy. just simply make them

[SeanB]

I think if i show this to a toolmaker I know he will cry, you have a very nice setup there that he cannot even dream of having.

[dcel]

I will say sir you have indeed constructed the ultimate kelvin clip! Congrats. Great video!

     My father was a machinst for 30 yrs and the skill is slowly becoming a lost art. There was a job fair here in West Michigan where a company from Wisconsin was hiring and moving machinist to their state to work and teach the next generation of machinist. They were paying the "teachers" and students well for the "education" because they could no longer find people there with your skillset. It was such a big deal here that it made the evening news for a few nights.

      Back on topic.... Have you thought about the actual contact resistance? Get yourself a can of Caig DeoxIT and ProGold. You own a microOhm meter, you can prove it to yourself and members here that it actually works. ( No affiliation, just a long time user. ) It will preserve the silver in your expensive looking connectors from tarnishing and improve the conductivity of the connection. I just thought you might be intrested in something that would help your quest for accurate microOhm measurements.

Chris

[dda]

I find this so amazing. Such a beautiful piece of equipment you have made.

[robrenz]

I will say sir you have indeed constructed the ultimate kelvin clip! Congrats. Great video!

Thanks, I thank God for the talents he has given.

     My father was a machinst for 30 yrs and the skill is slowly becoming a lost art. There was a job fair here in West Michigan where a company from Wisconsin was hiring and moving machinist to their state to work and teach the next generation of machinist. They were paying the "teachers" and students well for the "education" because they could no longer find people there with your skillset. It was such a big deal here that it made the evening news for a few nights.

I wish the younger generation (and their parents) would realize how fulfilling and profitable Machinist/Toolmaker careers can be.

      Back on topic.... Have you thought about the actual contact resistance? Get yourself a can of Caig DeoxIT and ProGold. You own a microOhm meter, you can prove it to yourself and members here that it actually works. ( No affiliation, just a long time user. ) It will preserve the silver in your expensive looking connectors from tarnishing and improve the conductivity of the connection. I just thought you might be intrested in something that would help your quest for accurate microOhm measurements.

Every contact in my lab has a Caig product on it.  The pincer tips have Pro gold as do the connector to my my micro-ohmeter.  If agilent says to use it on the 34420 Nanovoltmeter/micro-ohmeter contacts it must be good stuff.

Chris

[nanofrog]

I wish the younger generation (and their parents) would realize how fulfilling and profitable Machinist/Toolmaker careers can be.

Rob, where would someone even learn this skill these days?

I ask, as taking a quick look at the local Technical/Trade Schools in my area, there's no machinist program at all. So I'm wondering how many still offer it, or where it might be learned outside of the military (I'm too old for this one).

Thanks. 

[robrenz]

There are still Technical/trade schools that have machining programs but as in most occupations you only learn enough to not hurt yourself in school.  The real practical learning starts on the job. There are many companies that have very good internal training programs because that is the only way they can develop the skilled help necessary for the level of work they do. 

[chrome]

Here in Belgium the school I went too definitely taught machining, we had a large machining area with tons of lathe's, mills, drill, cnc's etc etc.
I kind of wanted to also do that but it was either electricity, mechanical+electricity or mechanical and to me it seemed like mechanical+electricity was basically both but you didn't see enough of either.

[SeanB]

I have seen some young apprentices, they are goo, but the results vary. John is a good trainer, and he will at least have taught all his prospective apprentices something more than what they came in with. You have got to admire a guy who does rough work to 0.1mm accuracy. Fine work comes out with a near mirror finish, only place you find tool marks are in screw holes and under welds.

[chrome]

I would also say that it's not as easy to get into machining yourself since the equipment is pretty expensive compared to other hobbies.

[IanB]

I would also say that it's not as easy to get into machining yourself since the equipment is pretty expensive compared to other hobbies.

Not necessarily. You need a good space for a workshop, but there are plenty of less expensive ways to get tools, either new or second hand. Part of the learning exercise is starting with a tool of average quality and tuning it up to have less play, better tolerances, smoother action and so on. Once you have a few tools you can use them to make new and better parts to upgrade what you have.

There are many hobbyists out there who make model steam engines and other mechanical devices in their home workshop. If you're really enthusiastic you can have a home foundry to complement your machine shop and then you can make almost anything.

[robrenz]

@ chrome ; Very true. Fortunately I make my living out of my home shop.  I would not be able to justify all this equipment for a hobby.