Crimping large cable lugs without a crimper

Sure. I actually have no objection to stereotyping of, say, Chinese businessmen. But it is good to find real causes of their behavior.

i

Yep.

Reply to
Ignoramus3498
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Similar to the bolt cutter grinding approach, you can buy versions with it already part of the blades. You can buy them at the hardware store for about 60 bucks depending on the size. They are actually designed for crimping/swaging connectors on wire cable (the structural kind). We also use them on large size crimp-on terminals. Our crimper, which is the smaller of the two sizes, will crimp up to 1/8" wire cable or the crimp connector on #6 wire. The larger version will crimp up to

1/4" wire so I would assume it would probably do up to about 2/0 connectors. We crimp our connecters first and then drip molten solder down the gaps to help with the electrical conductivity.
Reply to
woodworker88

And I've got a half dozen atwater kent radios that have been well used over the years. They all use simple lap joints and none of them have any degradation.

Look the properties of lead tin solder are well known. It doesn't cold flow, it doesn't work harden. If something is attacking lead tin solder chemically, wrapping the wire around the terminal a half dozen times isn't going to help. The joint's still going to fail.

Solder joints rely explicitly on the mechanical properties of the solder to form a gas-tight joint. Think about it: if the mechanical connection has a chance to take *any* strain then the gas-tight nature of the joint's been compromised.

All that mil-spec gear looks great (and I love the aroma, too) and it was a great idea to quantify the skills and train the solderers in a uniform fashion. But the joints are excessive IMO.

Jim

Reply to
jim rozen

Reply to
Don Murray

Yes it exists.

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ButI can not read what die takes. Don

Reply to
Don Murray

Don, thank you, I won that auction. I will try to look for proper dies for them, mostly #1, #2, $4 etc.

i
Reply to
Ignoramus3498

| Soldering, correctly done, is probably the best method for electrical | conductance, but solder isn't an acceptable mechanical joint. In many code | jurisdictions, soldering is prohibited -- mostly because many people won't | or can't do it well, but also because of the mechanical weakness of the | joint. | | They always taught us in electronics schools, "Make a secure mechanical-wrap | before soldering; solder isn't glue." | | LLoyd

I stayed out of this one to see what would come up, but what I've seen and worked has yet to be mentioned, so I'll offer my experience:

  1. Cold joints started out as bad from the very beginning. It's only by luck that they passed through life without causing a problem, so it's not a matter of _if_ they fail, it's when. Only when corrosion and moisture can work its way down inside the joint defect will the mechanical contact that got the joint by for so long will send the joint into final electrical failure. You can go a long way towards not having cold joint problems by using eutectic solder (63/37) which doesn't have that temperature zone the joint passes through where movement will cause crystallization and separation of one component of the alloy. I can't recall for sure which component has a lower melting point (tin?) that will crystallize.
  2. What we often call a cold joint is really an incomplete flow of the joint, in other words, a bad fillet with insufficient wetting. The flux can't be removed from inside the joint, so eventually the above failure mode pops up. Often there's a mechanical failure involved, too. Flux has this lovely habit of attracting moisture, which is why the flux must be removed. Acid fluxes are very bad for electrical and electronic connections for similar reasons.
  3. Stranded wires and soldering are rarely a good idea unless the wire connection can be supported. If soldering stranded wires, a heat sink should be used to prevent wicking of solder up inside the strands of the wire. Where the rigid solder-soaked strands stop and flexible wire begins there will be a spot highly prone to fatigue, and a guaranteed place to break. When soldering stranded wires to terminations for whatever reason, you MUST provide mechanical support, either in the form of a shrink sleeving, mechanical support such as ties or clamps, or whatever suits the application. It's more expensive tooling-wise to crimp wires, but the strands have an evenly tapered flex section that distributes mechanical movement over a larger part of the wire, thus reducing fatigue. Soldering solid wire strands to a terminal is no big deal, usually, since the wire itself is the mechanical support, but only in purely static equipment will solid wiring ever be used. It's also a lot harder to work with, as many know.
  4. For the sake of welding cable, flexibility and high current capacity is the reason for the high strand count. The less strands you have for a given outside diameter the less circular area (thus ampacity) and less flexibility you have. Since the individual strands are that much smaller, crimping is even more critical due to the lower individual strength of the strands, which will flake away at a soldered joint where the wicking ends. You can support the wire all you want, but for the hassle of keeping the wire from wicking and providing mechanical support either way, crimping is the more reliable way to go hands down.
  5. When the solder joint itself is the sole point of mechanical support, the solder alloy will fatigue, work harden, and fail just like any other metal will. Since the solder is so much softer than the metal it's joining, the conductor needs the mechanical support (either inside or out of the joint) to prevent the solder from being a stressed part of the connection. Electronic technicians are familiar with large components on circuit boards that must have mechanical support to keep things from ripping apart. I recall capacitors on an A-4 upper beacon which was always coming in with broken solder joints. I started securing it with a tie and RTV and never had one of my own repairs ever come back to me. How the A-4 managed to have a service life of over thirty years and not have that corrected baffles me still.

I really like what's called copalum splices and terminals, even for copper wire, because the intense pressure actually causes the aluminum to flow into and around the wire completely, making a 100% sealed and perfect connection, but they aren't cheap and the tooling even worse. The high quality of the connection is the reason they're used for aluminum terminals, since the lack of any resistance or corrosion entry point prevents any thermal movement which causes fatigue and fires and gave aluminum wiring a very bad name. The terminals allow aluminum wire to work to its best adantages.

If I made a boo-boo or need correction/clarification somewhere, by all means have at it!

Reply to
carl mciver

The high tech wire we used was 3/4" diameter > 1000 strand and would bend in a

4" radius. It took the 500 amp -2v current to the buss. (where others showed up)

Makes great jumper cables - so I am told. I got a harness, but the good stuff was gone. I got away with the 3/8" and 1/2" stuff. Have some fantastic 10 ga size that carries current!

Long lost the manufacturer of this very flexible and very high current wire. Using some in the current (high current that is) project now.

Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder

D> According to Ignoramus25589 :

Reply to
Martin H. Eastburn

4" radius.

Maybe DLO, Diesel Locomotive Cable?

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I used several parallel strands of the 777 MCM size on a project that required a flexible connection to carry 7500A @ 15V. For the last 2 feet all the current ran thru a water cooled jumper, much like the power cable on a water cooled TIG torch, that was about the size of your finger. We monitored the water flow very closely.

Ned Simmons

Reply to
Ned Simmons

This thread is almost over and everyone will go home without anyones mind being changed. But I will put in my bit anyway.

I think making a mechanical connection before soldering is usually a good thing. Not because it is needed after the joint is soldered, but because it prevents any movement while the joint is cooling. You all have seen the frosty look of a joint that was moved as the solder solidified. So I agree with Jim that a mechanical joint is not necessary, but it may prevent a " cold ' solder joint.

And then I agree with Carl too. A solder joint is only so strong. If it is being mechanically stressed very much it will fail. But if the solder is only supporting a short bit of wire, the stress will be well below the yield point of the solder, and you won't have any fatigue problems.

And I think the reason you should not tin stranded wires being held by screws, is not so much that solder cold flows, but you do have thermal changes to contend with. You get the solder deforming when there is expansion, and then oxygen can get in when there is contraction.

Dan

Reply to
dcaster

carries current!

I ran into some info on using fine stranded power cable (eg. for wiring up solar cell arrays), but didn't save the link. Apparently, the crimp is lot more critical than with coarsly stranded wire-- if you don't practically mush all the strands together into solid metal it can fail catastrophically fairly easily.

Best regards, Spehro Pefhany

Reply to
Spehro Pefhany

According to Ignoramus3498 :

Congratulations -- that is a nice price.

You won't *find* #1 dies. They are not part of the series. For that one, the choices are #8, #6, #4 and #2 -- *only*.

You also won't find crimp *terminals* specific for #1.

I think that the #2 will suffice for the #1 as well. In the smaller sizes, #16 (yellow) will also handle #14, and #10 (blue) will also handle #12. (And the next smaller size, red, is rated for #22-#16. The range seems to get smaller as the wire gets bigger.

The bigger crimp heads (separate hydraulic only -- you have to connect to your own pump if one is not part of the auction) are the #0 (1-0), 2-0, 3-0 and 4-0 -- all with separate dies for the same crimp head.

I just went down, and while I find the hydraulic heads, and the pumps easily enough, I don't find the container with the dies and the matching terminals. I'll have to try another time -- perhaps during the day instead of after 1:00 am, when I hit the newsgroup and see your postings, Perhaps a direct e-mail instead of a posting might get to me in time to go down in the daylight.

Enjoy, DoN.

Reply to
DoN. Nichols

According to Don Murray :

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Hmm ... Bundy -- yet another maker. AMP and T&B are fairly interchangeable in the pre-insulated terminals.

These look like they are un-insulate (just a color coding layer on the outside), so perhaps a #2 die would work well on these without the insulation. The starting bid is certainly attractive.

Thanks for the pointer -- I suspect that Igor should go for these terminals, as he is likely to have to pay that *each* for ones bought from a store. :-)

Enjoy, DoN.

Reply to
DoN. Nichols

I think you are talking about the color codes on the terminals? I was just looking in my junk box tonight for some terminals to use on 12 Ga wire. Yellow seemed to be the answer, but I only found a couple -- plenty of red and blue. Oh, well.

So I think maybe you got the gages and the colors confused -- or maybe there is something else going on that I don't know about. If the codes on my wimpy cheap cripmer are correct, red is 22-18, blue 16-14 and yellow 12-10.

Reply to
xray

On a related note, just how are you supposed to strip (ie. remove insulation from) these large cables? I've seen strippers up to 8 gauge, but nothing larger. I can't believe a utility knife is the proper tool.

Reply to
AL

There's a lot to this. I believe that until recently the Chinese government encouraged companies to make pirate copies of books, videos DVDs etc. Actually they might still, but I'd heard it was changing.

Chris

Reply to
Christopher Tidy

Here are two that I like to use.

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On a related note, just how are you supposed to strip (ie. remove insulation

Reply to
Don Murray

The color code repeats itself when you get bigger. I don't think it's quite so easy to mistake a 4 gauge terminal with a 16 gauge terminal (if blue is #4, I don't recall exactly)

Reply to
carl mciver

Harold sez: ". . .More likely due to corrosion . . ." That's about it - but - the joint has to be open in the first place for corrosion to occur. A good solder joint won't corrode to the extent of failure; a bad solder joint is already an "open" invitation for corrosion. Corroded joints act, electrically, as diodes. A piece of loose "tie-wrap" (tower jargon for radiator hose clamp) on a tower can form a diodes capable of supporting destructive intermodulation interference to receivers on the tower. That's probably what got into Harold's microphone. Motorola's famous engineer, Russ Larson, once found corrosion inside a large neon sign to be the cause of extreme intermod on a building antenna site in Kansas City. Russ proved the point by pouring some motor oil down into the sign. This type of corrosion-diode formed interference is recorded ad infinitum in the history of crowded radio communications sites.

Bob Swinney

. I've experienced such a phenomenon on a

Reply to
Robert Swinney

"AL" wrote in message news:UridnShG snipped-for-privacy@comcast.com... | On a related note, just how are you supposed to strip (ie. remove insulation | from) these large cables? I've seen strippers up to 8 gauge, but nothing | larger. I can't believe a utility knife is the proper tool.

Works fine. Just mind what you're doing. Use a very sharp blade (I always start with a brand new blade,) score the insulation and then rip it open. If that isn't enough, cut it deeper. My favorite thing is to score the insulation around circumferentially (sp?) first then bend the wire until it breaks. Once that's loose, pull it off. If necessary I'll score into the slug longways, but the idea is that when you pull it off, the strands are clean and still lay in place. Some folks cut it away like they were sharpening a pencil, but they make sure the blade angle is such that the edge won't cut into the metal when it gets there. The standards I have to work to won't allow that because of the potential for error on critical lengths.

Reply to
carl mciver

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