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Re: How does crimping work?


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If by fully insulated you mean the red blue and yellow types available in
a variety of configurations - the colour determining the cable sizes
catered for -  they vary wildly in quality by maker, as do the crimp
tools. Some seem to be made out of 'silver' foil. But even with the best,
it's interesting to cut off the insulation after crimping and examine the
quality of the crimp, especially at the bottom end of the range catered
for. To me, the only really satisfactory crimp is the type that forms a
heart shaped cross section after crimping - and those don't.  
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    Dave Plowman         snipped-for-privacy@davenoise.co.uk           London SW
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Re: How does crimping work?


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http://www.jaycar.com.au/productView.asp?ID=PT4525

The particular application is connecting to the terminals of an SLA, so
these connectors have the advantage of minimising the scope for
extraneous contact when they're in place.

Shame they perform so badly on the pull test.

Sylvia.

Re: How does crimping work?


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I too have seen these red terminals pull off a cable within their stated
range.

I prefer non insulated 1/4 in spade connectors that have a separate
insulating cover. They have a better cable clamp too. This sort:-

http://www.vehicle-wiring-products.eu/VWP-onlinestore/terminalsnonins/noninsblades.php

Made of brass, strangely. ;-)

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    Dave Plowman         snipped-for-privacy@davenoise.co.uk           London SW
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Re: How does crimping work?


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http://www.vehicle-wiring-products.eu/VWP-onlinestore/terminalsnonins/noninsblades.php
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I've noticed what is probably a significant difference between the
failed lugs, and the other type that seem OK. It lies in the length of
the metal that gets crimped.

The tool I'm using is one of these:

http://www.dse.com.au/cgi-bin/dse.storefront/4b15ceb90184983c273fc0a87e0106a4/Product/View/T3535

It seems designed to crimp equally* two locations spaced apart.

But the metal on the failed lugs is too short, and one side of the tool
is just crimping plastic.

[*] I emphasis "equally". Lest anyone think I've misunderstood, this is
not a tool designed to crimp the conductor and insulator in one go.

Sylvia.


Re: How does crimping work?


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http://www.vehicle-wiring-products.eu/VWP-onlinestore/terminalsnonins/noninsblades.php
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http://www.dse.com.au/cgi-bin/dse.storefront/4b15ceb90184983c273fc0a87e0106a4/Product/View/T3535
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The smaller of the two crimps is for the cable connection and the larger
bit just crimps the lug insulation round the cable insulation.

Re: How does crimping work?


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http://www.vehicle-wiring-products.eu/VWP-onlinestore/terminalsnonins/noninsblades.php
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http://www.dse.com.au/cgi-bin/dse.storefront/4b15ceb90184983c273fc0a87e0106a4/Product/View/T3535
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As I said, they are equal.

Sylvia.

Re: How does crimping work?


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http://www.vehicle-wiring-products.eu/VWP-onlinestore/terminalsnonins/noninsblades.php
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http://www.dse.com.au/cgi-bin/dse.storefront/4b15ceb90184983c273fc0a87e0106a4/Product/View/T3535
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Have a closer look, there is not much difference. Yours may be equal
mine is not. In any case the right side or the flat side is for the
cable connection and the left for the insulation.
They may have changed the design as I noticed my crimper does not work
as well with the newer lugs that seem to have different insulation.

Re: How does crimping work?


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http://www.vehicle-wiring-products.eu/VWP-onlinestore/terminalsnonins/noninsblades.php
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http://www.dse.com.au/cgi-bin/dse.storefront/4b15ceb90184983c273fc0a87e0106a4/Product/View/T3535
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By right side I mean the opposite side than that shown on your crimper

Re: How does crimping work?


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http://www.vehicle-wiring-products.eu/VWP-onlinestore/terminalsnonins/noninsblades.php
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http://www.dse.com.au/cgi-bin/dse.storefront/4b15ceb90184983c273fc0a87e0106a4/Product/View/T3535
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If these aren't identical, it's going to take measuring instruments to
prove it.

Crimping the plastic is a waste of time anyway. On the failed lugs that
I crimped, the plastic that covers the insulation has returned almost to
its original shape, even though the tool squashes it pretty much flat.

I know that there are tools designed to crimp this sort of lug

http://au.farnell.com/jst-japan-solderless-terminals/sto-1-0t-250n/terminal-female-6-3x0-8mm/dp/3625436

in one action, where the section closer to the spade crimps the
conductor, and the section at the end crimps the insulation, but the
tool I have is definitely not one of those.

Sylvia.

Re: How does crimping work?


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Something wrong there. The plastic acts as the cord clamp.

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    Dave Plowman         snipped-for-privacy@davenoise.co.uk           London SW
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Re: How does crimping work?


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Clearly doesn't work in the case of these particular lugs.

Sylvia.

Re: How does crimping work?


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Indeed. I do have a crimp tool supplied by one of the bigger insulated
crimp makers and I'll post some pics of the result later.

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    Dave Plowman         snipped-for-privacy@davenoise.co.uk           London SW
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Re: How does crimping work?


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Exactly. It's there for strain relief.

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Re: How does crimping work?


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In the example I posted earlier, which has strain relief, it's metal
that's crimped onto the insulator, not plastic.

Sylvia.

Re: How does crimping work?


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The standard crimp tool for insulated terminals has parallel jaws, and
those terminals have no provision for the metal part to crimp onto the
insulation. Nor will the insulation fit inside the metal part if you're
using the correct size, or at least with most cables. A very thin wall
type might. But the design calls for all the metal part of the crimp to be
in contact with the conductor.

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    Dave Plowman         snipped-for-privacy@davenoise.co.uk           London SW
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Re: How does crimping work?


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In the example I posted earlier

http://members.optusnet.com.au/sylviae/crimp.jpg

note how the lug on the left has a different diameter where it's crimped
around the insulation to where it's crimped around the conductor. That
difference existed prior to crimping - the diameter of the hole for the
wire changes part of the way down the shaft so that insulation cannot go
any further.

It's true that this difference is not obviously reflected in the tool I
used, but given that plastic deforms much more easily than metal, I can
believe that having jaws the same size works out OK (it certainly seems
to), and has the advantage that there's no right-way around to insert
the lug into the tool.

Sylvia.


Re: How does crimping work?


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IMHO, that type of crimp would require a special tool - not the generic
type for these pre-insulated connectors.

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    Dave Plowman         snipped-for-privacy@davenoise.co.uk           London SW
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Re: How does crimping work?


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The tool I have works much better on that type of connector than it does
on the type where the lug metal doesn't extend back over the cable
insulator. In the latter case, it merely squeezes some plastic which
then returns to more or less its original shape.

The tool may really be intended for lugs that crimp a longer section of
the conductor, but I haven't come across any such lugs.

Sylvia.

Re: How does crimping work?


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The proper crimp tool for the small insulated lugs as far as I know has
two crimping sections separated by a gap which is designed to crimp both
the conducting section on to the cable and the plastic on the lug to the
cable insulation at the same time.The cheaper tool which is more common
does one operation at a time (once for the cable crimp and once for the
insulation)I think that sylvia's lugs have a heavier section for copper
to copper and a flimsy copper skirt which continues back inside the
plastic insulation over the cable insulation but I may be wrong.

Re: How does crimping work?


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So? It still relieves strain on the metal-to-metal joint.

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