How does crimping work?

[Sylvia Else]

Bob Larter wrote:

Dave Plowman (News) wrote:
In article <00879530$0$8181$c3e8da3@news.astraweb.com>,
Sylvia Else <sylvia@not.at.this.address> wrote:
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.

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

Exactly. It's there for strain relief.

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

Sylvia.

 

[Bob Larter]

xpost test

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[Bob Larter]

Sylvia Else wrote:

F Murtz wrote:
Sylvia Else wrote:
F Murtz wrote:
Sylvia Else wrote:
F Murtz wrote:
Sylvia Else wrote:
Dave Plowman (News) wrote:
In article <0073ddf9$0$8184$c3e8da3@news.astraweb.com>,
Sylvia Else <sylvia@not.at.this.address> wrote:
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.

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.

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. ;-)


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.

The smaller of the two crimps is for the cable connection and the
larger bit just crimps the lug insulation round the cable insulation.

As I said, they are equal.

Sylvia.
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.

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.
The tool designed for that sort of lug has a knife edge bit in one
side of the crimp jaws which make a heart shape of the crimp.
Your crimper looks the same as mine in the jaws with the exception of
the size variation I am certain that the flat side or right side
goes toward the lug
and the side that sticks out is the cable side and is designed to
crimp the lug insulation to the cable insulation.
If you place the lug in the jaws with the cable side on the left you
will see that the crimps line up to do what I described.I am going to
check and may buy one similar to yours because some of my new lugs do
not fit old one with bigger insulation crimp on left.

Here are two insulated lugs that I crimped with mine, from which I then
stripped the insulation.

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

Note how the one on the left, which I bought from Dick Smith Electronics
(DSE), has crimped the insulation as well,

That's for strain-relief - it's a good thing.

whereas the one on the right,
with the shorter crimped section has not.

That's the cheaper version.


--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[Bob Larter]

Dave Plowman (News) wrote:

In article <00879530$0$8181$c3e8da3@news.astraweb.com>,
Sylvia Else <sylvia@not.at.this.address> wrote:
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.

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

Exactly. It's there for strain relief.

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[Sylvia Else]

Dave Plowman (News) wrote:

In article <0076c844$0$16926$c3e8da3@news.astraweb.com>,
Sylvia Else <sylvia@not.at.this.address> wrote:
Bob Larter wrote:
Dave Plowman (News) wrote:
In article <00879530$0$8181$c3e8da3@news.astraweb.com>,
Sylvia Else <sylvia@not.at.this.address> wrote:
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.
Something wrong there. The plastic acts as the cord clamp.
Exactly. It's there for strain relief.


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

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.

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.

 

[F Murtz]

Dave Plowman (News) wrote:

In article<0076c844$0$16926$c3e8da3@news.astraweb.com>,
Sylvia Else<sylvia@not.at.this.address> wrote:
Bob Larter wrote:
Dave Plowman (News) wrote:
In article<00879530$0$8181$c3e8da3@news.astraweb.com>,
Sylvia Else<sylvia@not.at.this.address> wrote:
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.

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

Exactly. It's there for strain relief.


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

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.

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.

 

[Dave Plowman (News)]

In article <0076c844$0$16926$c3e8da3@news.astraweb.com>,
Sylvia Else <sylvia@not.at.this.address> wrote:

Bob Larter wrote:
Dave Plowman (News) wrote:
In article <00879530$0$8181$c3e8da3@news.astraweb.com>,
Sylvia Else <sylvia@not.at.this.address> wrote:
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.

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

Exactly. It's there for strain relief.


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

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.

--
*Sticks and stones may break my bones but whips and chains excite me*

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Dave Plowman (News)]

In article <0094bf1a$0$26897$c3e8da3@news.astraweb.com>,
Sylvia Else <sylvia@not.at.this.address> wrote:

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.

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

--
*Arkansas State Motto: Don't Ask, Don't Tell, Don't Laugh.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Sylvia Else]

Dave Plowman (News) wrote:

In article <0094bf1a$0$26897$c3e8da3@news.astraweb.com>,
Sylvia Else <sylvia@not.at.this.address> wrote:
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.

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

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.

 

[Ross Herbert]

On Tue, 01 Dec 2009 00:46:08 +0000 (GMT), "Dave Plowman (News)"
<dave@davenoise.co.uk> wrote:

:In article <7nj3mqF3m9jbuU1@mid.individual.net>,
: Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au> wrote:
:> > Depends on the use. I'd say the most common crimp terminals are in
:> > some form of spring loaded contact.
:
:> **We're discussing CRIMP terminals. Like this:
:
:> http://www.ami.ac.uk/courses/topics/0119_crmp/index.html
:
:> Copper is the material, not brass.
:
:Heavy duty electrical ones may be - but the most common ones like in
:computers and cars are brass.


Aha! Now you have finally made the distinction in your argument...

Commonly used terminals in the whitegoods and automotive areas (ie. QC crimp
terminals) are indeed made of brass. But that is about the limit of use for this
material. When it comes to electrical crimp lugs, spade terminals etc, then the
lug/terminal material is always copper, unless you are using aluminium
conductors where the terminal material will be aluminium.

Take a look at the Utilux catalogue (small insulated and un-insulated terminals)
http://www.utilux.com.au/pdf/4.pdf and you will see mentioned at the top of
several pages the material is electro-tinned copper. Only the QC tabs are brass.

 

[Dave Plowman (News)]

In article <kg0mh5d3rvkij3o71ogh0lgdipcdlv8ves@4ax.com>,
Ross Herbert <rherber1@bigpond.net.au> wrote:

Aha! Now you have finally made the distinction in your argument...

Made it pretty well from the start. As I got the impression the OP wasn't
talking about heavy duty power connections.

Commonly used terminals in the whitegoods and automotive areas (ie. QC
crimp terminals) are indeed made of brass. But that is about the limit
of use for this material. When it comes to electrical crimp lugs, spade
terminals etc, then the lug/terminal material is always copper, unless
you are using aluminium conductors where the terminal material will be
aluminium.

Almost anywhere you go, there will be more crimped terminals which aren't
copper - as they are sprung as part of a plug and socket arrangement. Many
inside your computer, for a start. TV as well. Etc.

--
*If you ate pasta and anti-pasta, would you still be hungry?

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.

 

[Bob Larter]

Sylvia Else wrote:

Bob Larter wrote:
Dave Plowman (News) wrote:
In article <00879530$0$8181$c3e8da3@news.astraweb.com>,
Sylvia Else <sylvia@not.at.this.address> wrote:
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.

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

Exactly. It's there for strain relief.


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

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

--
W
. | ,. w , "Some people are alive only because
\|/ \|/ it is illegal to kill them." Perna condita delenda est
---^----^---------------------------------------------------------------

 

[Van Chocstraw]

On 11/30/2009 07:54 AM, Sylvia Else wrote:

The obvious answer is that you bend the metal of the connector so that
it holds the wire in place.

This doesn't seem very satisfactory. Metal always retains some
flexibility, even when bent beyond its yield point. No matter how hard
you squeeze, there'll be some rebound when you release the pressure,
which should result in a loose joint.

After having had a bad experience trying to crip a lug some years ago, I
recently faced the need to do this again. So I bought a moderately
expensive ratchet based crimping tool. And, rather to my surprise, it
actually works.

But that doesn't answer the question of how.

Sylvia.

Crimping is an emergency fix to me. It's a piss poor connection that can
corrode and pull apart. I always use solder after crimping.

 

[F Murtz]

Van Chocstraw wrote:

On 11/30/2009 07:54 AM, Sylvia Else wrote:
The obvious answer is that you bend the metal of the connector so that
it holds the wire in place.

This doesn't seem very satisfactory. Metal always retains some
flexibility, even when bent beyond its yield point. No matter how hard
you squeeze, there'll be some rebound when you release the pressure,
which should result in a loose joint.

After having had a bad experience trying to crip a lug some years ago, I
recently faced the need to do this again. So I bought a moderately
expensive ratchet based crimping tool. And, rather to my surprise, it
actually works.

But that doesn't answer the question of how.

Sylvia.

Crimping is an emergency fix to me. It's a piss poor connection that can
corrode and pull apart. I always use solder after crimping.
solder is not as flexible and causes more trouble than crimping in some

circumstances (in areas of vibration etc)

 

[Trevor Wilson]

"Van Chocstraw" <boobooililililil@roadrunner.com> wrote in message
newsKydndsHEfSm583WnZ2dnUVZ_q5i4p2d@giganews.com...

On 11/30/2009 07:54 AM, Sylvia Else wrote:
The obvious answer is that you bend the metal of the connector so that
it holds the wire in place.

This doesn't seem very satisfactory. Metal always retains some
flexibility, even when bent beyond its yield point. No matter how hard
you squeeze, there'll be some rebound when you release the pressure,
which should result in a loose joint.

After having had a bad experience trying to crip a lug some years ago, I
recently faced the need to do this again. So I bought a moderately
expensive ratchet based crimping tool. And, rather to my surprise, it
actually works.

But that doesn't answer the question of how.

Sylvia.

Crimping is an emergency fix to me. It's a piss poor connection that can
corrode and pull apart. I always use solder after crimping.

**Then you're doing it wrong.


--
Trevor Wilson
www.rageaudio.com.au

 

[Ray]

"Trevor Wilson" <trevor@rageaudio.com.au> wrote in
news:7rc2f8F8rnU1@mid.individual.net:

"Van Chocstraw" <boobooililililil@roadrunner.com> wrote in message
newsKydndsHEfSm583WnZ2dnUVZ_q5i4p2d@giganews.com...
On 11/30/2009 07:54 AM, Sylvia Else wrote:

After having had a bad experience trying to crip a lug some years
ago, I recently faced the need to do this again. So I bought a
moderately expensive ratchet based crimping tool. And, rather to my
surprise, it actually works.


Crimping is an emergency fix to me. It's a piss poor connection that
can corrode and pull apart. I always use solder after crimping.

**Then you're doing it wrong.

Yup, adding solder will make the connection brittle, and more prone to
failure in a vibration environment.

Crimping is actually far more reliable.