I use the Molex KK series of connectors extensively. In 1988 I purchased
a small crimper in the Akahabara (sp) in Tokyo and this works well. If
Memory serves, I paid approximately $10US for it. I would like to find
another crimper that won't break my bank (less than $20). I do not have
a need for an industrial strength, high production unit. Any suggestions
where I might find such a critter without having to go to Toyko?
I found the proper Molex ratchet crimper (xxx-2300?) to be worth every penny
(~$215USD).
Short of that I might try the simple universal molex crimper (digikey wm9999
? ~$50 ).
Cheap copies of ratchet crimpers have always caused us grief
>
> I use the Molex KK series of connectors extensively. In 1988 I purchased
> a small crimper in the Akahabara (sp) in Tokyo and this works well. If
> Memory serves, I paid approximately $10US for it. I would like to find
> another crimper that won't break my bank (less than $20). I do not have
> a need for an industrial strength, high production unit. Any suggestions
> where I might find such a critter without having to go to Toyko?
>
> Any enlightenment will be appreciated.
>
> Vic
> --
>
>
> *____________________________________________________________________________________________*
>
> *Victor Fraenckel
> KC2GUI
> victorf ATSIGN windreader DOT com**
> *
>
>
On Fri, 09 Nov 2007 07:27:44 -0500, Victor Fraenckel wrote:
> I use the Molex KK series of connectors extensively. In 1988 I purchased
> a small crimper in the Akahabara (sp) in Tokyo and this works well. If
> Memory serves, I paid approximately $10US for it. I would like to find
> another crimper that won't break my bank (less than $20). I do not have
> a need for an industrial strength, high production unit. Any suggestions
> where I might find such a critter without having to go to Toyko?
>
> Any enlightenment will be appreciated.
I too have used molex KK series connectors what seems like forever (almost
30 years!) I'm lucky in that I scavenged a genuine Molex KK ratcheting
crimp tool in a "grab bag" box of lab supplies that was being auctioned at
going out of business sale many years ago. The tool must be at least 25
years old but still works perfectly after 1000's of crimp operations.
That said, I'm always looking around for sources of crimpers and connectors
and found these:
Search for PHT-98-601 crimp tool (or scroll down near the bottom of the
page until you see it). Not bad at $39.90 for a ratcheting crimper. I have
*not* used this tool so I can't vouch for the quality but if it's as shown
in the picture appears to be a well made tool.
They also have very good prices on connectors and housings themselves. I
plan to order some to re-stock my lab kit. I may try the crimp tool
mentioned above.
> Short of that I might try the simple universal molex crimper (digikey wm9999
> ? ~$50 ).
I'm using this beast now, seems pretty good.
The one that's recommended for the pins I'm using is $800. (!)
I'm not sure how it's $750 worth of better..
Dave Lagzdin wrote:
> I found the proper Molex ratchet crimper (xxx-2300?) to be worth every penny
> (~$215USD).
> Short of that I might try the simple universal molex crimper (digikey wm9999
> ? ~$50 ).
>
Dave,
$215 is a bit rich for my blood, I'm afraid. I will check on the digikey
crimper though. Thanks for taking the time to reply.
Matt Pobursky wrote:
> I too have used molex KK series connectors what seems like forever (almost
> 30 years!) I'm lucky in that I scavenged a genuine Molex KK ratcheting
> crimp tool in a "grab bag" box of lab supplies that was being auctioned at
> going out of business sale many years ago. The tool must be at least 25
> years old but still works perfectly after 1000's of crimp operations.
>
I would never be lucky enough to stumble on to something like that! I
had a quick look at the Action-Electronics pages last night and will
study them more today. I am a bit confused, though, about which crimper
will work for me.
David VanHorn wrote:
>> Short of that I might try the simple universal molex crimper (digikey wm9999
>> ? ~$50 ).
>>
>
> I'm using this beast now, seems pretty good.
> The one that's recommended for the pins I'm using is $800. (!)
> I'm not sure how it's $750 worth of better..
$50 beats $800 every time in my budget! I will have a look at the
digikey suggestion though. Thanks for taking the time to reply.
>Dave Lagzdin wrote:
>
>
>>I found the proper Molex ratchet crimper (xxx-2300?) to be worth every penny
>>(~$215USD).
>>Short of that I might try the simple universal molex crimper (digikey wm9999
>>? ~$50 ).
>>
>>
>>
>
>Dave,
>
>$215 is a bit rich for my blood, I'm afraid. I will check on the digikey
>crimper though. Thanks for taking the time to reply.
>
>Vic
>
>*____________________________________________________________________________________________*
>
>*Victor Fraenckel
>KC2GUI
>victorf ATSIGN windreader DOT com**
>*
>
>
>
>
I have one I bought from Radio Shack that looks identical to the molex
wm9999. It cost me less then $20, that was maybe 5 Years ago. I
polished the female crimp die that curls the metal tabs back into the wire.
I only use it for hobby and some repair work.
Victor Fraenckel wrote:
> Matt Pobursky wrote:
>
>> I too have used molex KK series connectors what seems like forever (almost
>> 30 years!) I'm lucky in that I scavenged a genuine Molex KK ratcheting
>> crimp tool in a "grab bag" box of lab supplies that was being auctioned at
>> going out of business sale many years ago. The tool must be at least 25
>> years old but still works perfectly after 1000's of crimp operations.
>>
>>
> I would never be lucky enough to stumble on to something like that! I
> had a quick look at the Action-Electronics pages last night and will
> study them more today. I am a bit confused, though, about which crimper
> will work for me.
>
> Thanks for taking the time to reply.
>
>
In the not-so-distant past I consulted for some pretty big companies to
solve intermittent design problems.
Want to take a guess as to what is the cause of 99.9999% of all such
problems? Bad connections due to:
(1) poorly-designed connectors, such as the Molex KK. There is only ONE
wiping surface, which means
that even when properly installed, it is highly sensitive to vibration.
I am continually surprised that Molex
is still selling the KK pins and housings. It is worst than useless, it
is almost criminal.
(2) bad wire-to-pin crimps. Usually this is caused by handheld crimping
tools, which are unable to apply
enough force to the wire-pin surface. To be reliable, hydraulic crimping
tools should be used.
For small companies, the solution is to purchase wires with the crimps
already installed by hydraulic crimping
tools. MANY cable companies offer such crimping services, just call around.
So what is a good connection pin? Select one in which the pin grips the
post on at LEAST two sides with good
spring force. Mill-Max makes the very best wiping connectors for round
pins. Berg (now FLC?) makes the
best wiping connectors for square pins (MiniPV or MaxiPV) because their
powerful internal spring grips the post
like the bite of a junkyard dog.
Does gold make a difference? yes, but not initially. When a pin is
initially crimped, the tin/copper (wire) interface
is acceptable. But with time , the tin corrodes, whereas the gold (being
malleable and inert) maintains a good
connection. The fact that time is a factor causes even the best of
engineers to overlook the advantages of gold pins.
For the record, Molex DOES make some good pins (but KK isn't one of them).
I second the motion for BERG (FCI) being the best connector for square
posts.
We use these almost exclusively for our internal test fixtures because of
the reliability.
We have several house built test setups that have been running almost
continuously for
5 or 6 years using the BERG connectors. We have yet to have a machine break
down
because of these connectors. We have had down time due to other causes, but
not because
of the connectors.
They're a little pricey, but the reliability more than justifies the cost.
So, if you need a reliable connection that doesn't use loads of current,
BERG (FCI) is the
way to go.
> Does gold make a difference? yes, but not initially. When a pin is
> initially crimped, the tin/copper (wire) interface
> is acceptable. But with time , the tin corrodes, whereas the gold (being
> malleable and inert) maintains a good
> connection. The fact that time is a factor causes even the best of
> engineers to overlook the advantages of gold pins.
>
> For the record, Molex DOES make some good pins (but KK isn't one of them).
>
> --Bob A
For the 0.156" I have been using a KK contact with 3 wipers.
Yes, do wish they made the same for 0.10".
Even the C-grid grabs from 2 sides....
Victor Fraenckel wrote:
> I use the Molex KK series of connectors extensively. In 1988 I purchased
> a small crimper in the Akahabara (sp) in Tokyo and this works well. If
> Memory serves, I paid approximately $10US for it. I would like to find
> another crimper that won't break my bank (less than $20). I do not have
> a need for an industrial strength, high production unit. Any suggestions
> where I might find such a critter without having to go to Toyko?
>
> Any enlightenment will be appreciated.
>
> Vic
>
Vic,
Have you seen this link? http://www.marvin3m.com/connect/#good
----- Original Message ----
From: jim <.....jimKILLspam@spam@jpes.com>
To: Microcontroller discussion list - Public. <piclistKILLspammit.edu>
Sent: Saturday, November 10, 2007 9:51:46 AM
Subject: Re: [EE] Crimper Source
All,
I second the motion for BERG (FCI) being the best connector for square
posts.
We use these almost exclusively for our internal test fixtures because of
the reliability.
We have several house built test setups that have been running almost
continuously for
5 or 6 years using the BERG connectors. We have yet to have a machine break
down
because of these connectors. We have had down time due to other causes, but
not because
of the connectors.
They're a little pricey, but the reliability more than justifies the cost.
So, if you need a reliable connection that doesn't use loads of current,
BERG (FCI) is the
way to go.
part 1 6844 bytes content-type:text/plain; charset="us-ascii" (decoded quoted-printable)
Bob,
Usually you and I agree almost totally about things electronic but in this
case I can't agree...
On Sat, 10 Nov 2007 07:29:39 -0700, Bob Axtell wrote: {Quote hidden}
> Victor Fraenckel wrote:
>> Matt Pobursky wrote:
>>
>>> I too have used molex KK series connectors what seems like forever
>>> (almost 30 years!) I'm lucky in that I scavenged a genuine Molex KK
>>> ratcheting crimp tool in a "grab bag" box of lab supplies that was
>>> being auctioned at going out of business sale many years ago. The
>>> tool must be at least 25 years old but still works perfectly after
>>> 1000's of crimp operations.
>>>
>>>
>> I would never be lucky enough to stumble on to something like that! I
>> had a quick look at the Action-Electronics pages last night and will
>> study them more today. I am a bit confused, though, about which crimper
>> will work for me.
>>
>> Thanks for taking the time to reply.
>>
>>
> In the not-so-distant past I consulted for some pretty big companies to
> solve intermittent design problems.
> Want to take a guess as to what is the cause of 99.9999% of all such
> problems? Bad connections due to:
>
> (1) poorly-designed connectors, such as the Molex KK. There is only ONE
> wiping surface, which means
> that even when properly installed, it is highly sensitive to vibration. I
> am continually surprised that Molex
> is still selling the KK pins and housings. It is worst than useless, it
> is almost criminal.
My experience has been about 180º opposite yours. I've put millions, heck
with a quick count at least 10 Million+ KK connectors into production
products or production quality products. This would include all sorts of
medical devices, life safety equipment (mostly fire suppression systems),
all sorts of industrial controls, production test sets and the like. I've
never had *one* failure reported to me that was related to the KK connector
design. Believe me, most of these products are the type that I'll hear
about ANY failure almost immediately.
I don't find the KK connectors to be "highly sensitive to vibration", in
fact quite the opposite. Then again, I never use anything but the version
with locking ramps and side ribs. Once they are seated it takes several
pounds of pressure to unseat them. If vibration from the wire harness
itself causes a problem then it's a bad design and the wire harness should
be secured.
I wouldn't put them in an aircraft cockpit or underhood in a car but I
would feel comfortable using them almost anywhere else.
> (2) bad wire-to-pin crimps. Usually this is caused by handheld crimping
> tools, which are unable to apply
> enough force to the wire-pin surface. To be reliable, hydraulic crimping
> tools should be used.
This is one area we can mostly agree. The only KK related failures I've
seen were due to poor crimps. I believe that this is why the KK terminals
work so poorly for a lot of people. I've fixed a few production problems
related to this and improper crimping was almost always the culprit.
I do disagree however, that machine crimped pins are the only reliable
ones. A KK terminal crimped with a proper ratcheting crimp tool and the
correct dies will be indistinguishable from a machine crimped pin. I have
made this demonstration before -- take a wire crimped by me with my proper
hand tool and one machine crimped. They will look identical. Subject them
both to a pull test. Both crimps will hold and the wire will break before
the crimped wire pulls out. That's about as reliable a crimp as you can
get.
Most hand tools sold for Molex pins are crap. It has to be a ratcheting
crimper and it has to have correctly designed dies. Anything else is a toy
and should be avoided. That's why the typical $20 crimpers are virtually
always a *bad thing*. If you see a $20 crimper, run for the hills as you
will have problems with it sooner or later. I normally expect to pay at
least $50-80 (and sometimes a lot more) for a good quality ratcheting
crimper. The more obscure the pin you are wanting to crimp, generally the
more expensive the crimper will be.
> For small companies, the solution is to purchase wires with the crimps
> already installed by hydraulic crimping
> tools. MANY cable companies offer such crimping services, just call
> around.
Agreed. There are many production houses that specialize in wire harnesses
and terminal crimping. Most of the Contract Manufacturers I work with also
have well equipped wire harness assembly lines. They should have the proper
tools and know how to correctly crimp the wires. They typically will do a
better job, cheaper, than you can do it yourself (unless you invest in the
equipment to do it right).
> So what is a good connection pin? Select one in which the pin grips the
> post on at LEAST two sides with good
> spring force. Mill-Max makes the very best wiping connectors for round
> pins. Berg (now FLC?) makes the
> best wiping connectors for square pins (MiniPV or MaxiPV) because their
> powerful internal spring grips the post like the bite of a junkyard dog.
In general I agree with this too. But I've also seen multi-contact pins
that weren't worth spit too.
> Does gold make a difference? yes, but not initially. When a pin is
> initially crimped, the tin/copper (wire) interface
> is acceptable. But with time , the tin corrodes, whereas the gold (being
> malleable and inert) maintains a good
> connection. The fact that time is a factor causes even the best of
> engineers to overlook the advantages of gold pins.
At least partial agreement here again. I think it's highly application
dependent. I've found that gold pins and contacts are more reliable long
term, depending on the environment. I have *not* found any problems with
the tin contact/wire crimp interface at all. I've seen wires so corroded
that they were effectively gone, but the wire section of the crimp area was
still intact. It's pretty much a multi-contact gas tight fit when propoerly
crimped. If the corrosion is really that bad then I would argue it's a mis-
application of the connector (and probably the wire harness too) and should
be re-thought.
Bah, connectors are the devil's spawn anyway. The biggest failure mode of
electronic assemblies is the mechanical connections regardless how they're
done. I try to minimize connector usage as much as possible. Sadly, we must
design things that have to hookup to the outside world and can't avoid them
entirely...
> For the record, Molex DOES make some good pins (but KK isn't one of them).
>
> --Bob A
Matt Pobursky
Maximum Performance Systems
part 2 35 bytes content-type:text/plain; charset="us-ascii" (decoded 7bit)
On Sat, 10 Nov 2007 08:51:46 -0600, jim wrote:
> All,
>
> I second the motion for BERG (FCI) being the best connector for square
> posts. We use these almost exclusively for our internal test fixtures
> because of the reliability. We have several house built test setups that
> have been running almost continuously for 5 or 6 years using the BERG
> connectors. We have yet to have a machine break down because of these
> connectors. We have had down time due to other causes, but not because
> of the connectors.
>
> They're a little pricey, but the reliability more than justifies the cost.
>
> So, if you need a reliable connection that doesn't use loads of current,
> BERG (FCI) is the way to go.
Bah, 5-6 years? They're just infants. ;-)
I've got KK series connectors that have been running along for 20+ years in
equipment shacks in Saudi Arabia, Aluminum mills in South America and
Hydroelectric power plants all over the world world with no failures.
I do think FCI makes some good connectors as well. Other than asian knock-
offs, I feel pretty comfortable using connectors from most all the "big
name" connector suppliers. It's a matter of cost, application fit and
availability (both parts and tooling).
On Sat, 10 Nov 2007 10:04:11 -0500, Dave Lag wrote:
> Bob Axtell wrote:
>
>> Does gold make a difference? yes, but not initially. When a pin is
>> initially crimped, the tin/copper (wire) interface
>> is acceptable. But with time , the tin corrodes, whereas the gold
>> (being malleable and inert) maintains a good
>> connection. The fact that time is a factor causes even the best of
>> engineers to overlook the advantages of gold pins.
>>
>> For the record, Molex DOES make some good pins (but KK isn't one of
>> them).
>>
>> --Bob A
>>
> For the 0.156" I have been using a KK contact with 3 wipers. Yes, do wish
> they made the same for 0.10". Even the C-grid grabs from 2 sides....
Molex used to make a "box contact" for the 0.1" KK series connectors with
multiple wipe contacts. I used them in the distant past but didn't find
they performed any better (or worse) than the single leaf style contacts.
You might check their catalog to see if the still make them. I know that no
one used to stock them and we had to order reels of them so they may still
be in existence but hard to find.
On Sat, 10 Nov 2007 10:05:16 -0500, Gaston Gagnon wrote:
> Victor Fraenckel wrote:
>> I use the Molex KK series of connectors extensively. In 1988 I
>> purchased a small crimper in the Akahabara (sp) in Tokyo and this works
>> well. If Memory serves, I paid approximately $10US for it. I would like
>> to find another crimper that won't break my bank (less than $20). I do
>> not have a need for an industrial strength, high production unit. Any
>> suggestions where I might find such a critter without having to go to
>> Toyko?
>>
>> Any enlightenment will be appreciated.
>>
>> Vic
>>
> Vic,
> Have you seen this link?
> http://www.marvin3m.com/connect/#good
I think that's generally a very good page and anyone that uses crimp pins
ought to read it. Molex also has a similar application note on crimped pins
(it appears a lot of his information came from the Molex note).
I would disagree with his choice of crimpers though. I won't waste my time
on a non-ratcheting crimper anymore. The ratcheting crimpers take the user
error (at least not applying the right crimp pressure) out of the equation.
> Victor Fraenckel wrote:
>
>> Matt Pobursky wrote:
>>
>>
>>> I too have used molex KK series connectors what seems like forever (almost
>>> 30 years!) I'm lucky in that I scavenged a genuine Molex KK ratcheting
>>> crimp tool in a "grab bag" box of lab supplies that was being auctioned at
>>> going out of business sale many years ago. The tool must be at least 25
>>> years old but still works perfectly after 1000's of crimp operations.
>>>
>>>
>>>
>> I would never be lucky enough to stumble on to something like that! I
>> had a quick look at the Action-Electronics pages last night and will
>> study them more today. I am a bit confused, though, about which crimper
>> will work for me.
>>
>> Thanks for taking the time to reply.
>>
>>
>>
> In the not-so-distant past I consulted for some pretty big companies to
> solve intermittent design problems.
> Want to take a guess as to what is the cause of 99.9999% of all such
> problems? Bad connections due to:
>
> (1) poorly-designed connectors, such as the Molex KK. There is only ONE
> wiping surface, which means
> that even when properly installed, it is highly sensitive to vibration.
> I am continually surprised that Molex
> is still selling the KK pins and housings. It is worst than useless, it
>
Clarification: I am referring to the 0.1" kk pins, that are shaped like
the letter 'D'.
> is almost criminal.
>
> (2) bad wire-to-pin crimps. Usually this is caused by handheld crimping
> tools, which are unable to apply
> enough force to the wire-pin surface. To be reliable, hydraulic crimping
> tools should be used.
>
> For small companies, the solution is to purchase wires with the crimps
> already installed by hydraulic crimping
> tools. MANY cable companies offer such crimping services, just call around.
>
> So what is a good connection pin? Select one in which the pin grips the
> post on at LEAST two sides with good
> spring force. Mill-Max makes the very best wiping connectors for round
> pins. Berg (now FLC?) makes the
> best wiping connectors for square pins (MiniPV or MaxiPV) because their
> powerful internal spring grips the post
> like the bite of a junkyard dog.
>
> Does gold make a difference? yes, but not initially. When a pin is
> initially crimped, the tin/copper (wire) interface
> is acceptable. But with time , the tin corrodes, whereas the gold (being
> malleable and inert) maintains a good
> connection. The fact that time is a factor causes even the best of
> engineers to overlook the advantages of gold pins.
>
> For the record, Molex DOES make some good pins (but KK isn't one of them).
>
> --Bob A
>
BTW, there is one MORE source of connector problems: surface-mounted
connectors. Instead of being thru-hole
mounted, each post is tacked to a surface pad. These ARE _definitely_
criminal. The adhesive that holds the pad
to the PCB core does NOT have enough strength to accommodate the force
of connector removal, so the adhesive
breaks and the connector post wobbles until the foil of the pad finally
cracks apart.
ALL connectors that are removable with any force over 1/2kg MUST be
thru-hole.
> On Sat, 10 Nov 2007 10:04:11 -0500, Dave Lag wrote:
>
>> Bob Axtell wrote:
>>
>>
>>> Does gold make a difference? yes, but not initially. When a pin is
>>> initially crimped, the tin/copper (wire) interface
>>> is acceptable. But with time , the tin corrodes, whereas the gold
>>> (being malleable and inert) maintains a good
>>> connection. The fact that time is a factor causes even the best of
>>> engineers to overlook the advantages of gold pins.
>>>
>>> For the record, Molex DOES make some good pins (but KK isn't one of
>>> them).
>>>
>>> --Bob A
>>>
>>>
>> For the 0.156" I have been using a KK contact with 3 wipers. Yes, do wish
>> they made the same for 0.10". Even the C-grid grabs from 2 sides....
>>
>
> Molex used to make a "box contact" for the 0.1" KK series connectors with
> multiple wipe contacts. I used them in the distant past but didn't find
> they performed any better (or worse) than the single leaf style contacts.
> You might check their catalog to see if the still make them. I know that no
> one used to stock them and we had to order reels of them so they may still
> be in existence but hard to find.
>
> Matt Pobursky
> Maximum Performance Systems
>
>
Good comments.
There was solid analysis done on what was happening to the kk
connectors, using a laboratory to assist
us. What was happening was that high current sometimes flowed through
some of the connector pins. Over time-
and not much was needed- the springiness of the connector faded due to
the high current it was handling,
and the contact pressure lessened and lessened until there was almost NO
electrical contact. I decided
that if the connector had been sturdier, the problem wouldn't have
occurred, although we could have
fixed it by (1) better sharing the load at the connector pins; (2)
replacing the post with a gold-plated or
smoother one (high spots on the post plating were contributing to "hot
spots"); increasing the number of
pins used. We fixed it by replacing the post AND the connector type; I
wanted berg MiniPV but the
client settled on a quality AMP gold connector and a gold-plated post, I
think from 3M. In any case, the
problem completely went away.
Matt Pobursky wrote:
> Bob,
>
> Usually you and I agree almost totally about things electronic but in this
> case I can't agree...
>
>
I noticed that, too; I think our experience runs (or ran) along the same
path.
> On Sat, 10 Nov 2007 07:29:39 -0700, Bob Axtell wrote:
>
>> Victor Fraenckel wrote:
>>
>>> Matt Pobursky wrote:
>>>
>>>
>>>> I too have used molex KK series connectors what seems like forever
>>>> (almost 30 years!) I'm lucky in that I scavenged a genuine Molex KK
>>>> ratcheting crimp tool in a "grab bag" box of lab supplies that was
>>>> being auctioned at going out of business sale many years ago. The
>>>> tool must be at least 25 years old but still works perfectly after
>>>> 1000's of crimp operations.
>>>>
>>>>
>>>>
>>> I would never be lucky enough to stumble on to something like that! I
>>> had a quick look at the Action-Electronics pages last night and will
>>> study them more today. I am a bit confused, though, about which crimper
>>> will work for me.
>>>
>>> Thanks for taking the time to reply.
>>>
>>>
>>>
>> In the not-so-distant past I consulted for some pretty big companies to
>> solve intermittent design problems.
>> Want to take a guess as to what is the cause of 99.9999% of all such
>> problems? Bad connections due to:
>>
>> (1) poorly-designed connectors, such as the Molex KK. There is only ONE
>> wiping surface, which means
>> that even when properly installed, it is highly sensitive to vibration. I
>> am continually surprised that Molex
>> is still selling the KK pins and housings. It is worst than useless, it
>> is almost criminal.
>>
>
> My experience has been about 180º opposite yours. I've put millions, heck
> with a quick count at least 10 Million+ KK connectors into production
> products or production quality products. This would include all sorts of
> medical devices, life safety equipment (mostly fire suppression systems),
> all sorts of industrial controls, production test sets and the like. I've
> never had *one* failure reported to me that was related to the KK connector
> design. Believe me, most of these products are the type that I'll hear
> about ANY failure almost immediately.
>
> I don't find the KK connectors to be "highly sensitive to vibration", in
> fact quite the opposite. Then again, I never use anything but the version
> with locking ramps and side ribs. Once they are seated it takes several
> pounds of pressure to unseat them. If vibration from the wire harness
> itself causes a problem then it's a bad design and the wire harness should
> be secured.
>
> I wouldn't put them in an aircraft cockpit or underhood in a car but I
> would feel comfortable using them almost anywhere else.
>
>
>> (2) bad wire-to-pin crimps. Usually this is caused by handheld crimping
>> tools, which are unable to apply
>> enough force to the wire-pin surface. To be reliable, hydraulic crimping
>> tools should be used.
>>
>
> This is one area we can mostly agree. The only KK related failures I've
> seen were due to poor crimps. I believe that this is why the KK terminals
> work so poorly for a lot of people. I've fixed a few production problems
> related to this and improper crimping was almost always the culprit.
>
> I do disagree however, that machine crimped pins are the only reliable
> ones. A KK terminal crimped with a proper ratcheting crimp tool and the
> correct dies will be indistinguishable from a machine crimped pin. I have
> made this demonstration before -- take a wire crimped by me with my proper
> hand tool and one machine crimped. They will look identical. Subject them
> both to a pull test. Both crimps will hold and the wire will break before
> the crimped wire pulls out. That's about as reliable a crimp as you can
> get.
>
> Most hand tools sold for Molex pins are crap. It has to be a ratcheting
> crimper and it has to have correctly designed dies. Anything else is a toy
> and should be avoided. That's why the typical $20 crimpers are virtually
> always a *bad thing*. If you see a $20 crimper, run for the hills as you
> will have problems with it sooner or later. I normally expect to pay at
> least $50-80 (and sometimes a lot more) for a good quality ratcheting
> crimper. The more obscure the pin you are wanting to crimp, generally the
> more expensive the crimper will be.
>
>
>> For small companies, the solution is to purchase wires with the crimps
>> already installed by hydraulic crimping
>> tools. MANY cable companies offer such crimping services, just call
>> around.
>>
>
> Agreed. There are many production houses that specialize in wire harnesses
> and terminal crimping. Most of the Contract Manufacturers I work with also
> have well equipped wire harness assembly lines. They should have the proper
> tools and know how to correctly crimp the wires. They typically will do a
> better job, cheaper, than you can do it yourself (unless you invest in the
> equipment to do it right).
>
>
>> So what is a good connection pin? Select one in which the pin grips the
>> post on at LEAST two sides with good
>> spring force. Mill-Max makes the very best wiping connectors for round
>> pins. Berg (now FLC?) makes the
>> best wiping connectors for square pins (MiniPV or MaxiPV) because their
>> powerful internal spring grips the post like the bite of a junkyard dog.
>>
>
> In general I agree with this too. But I've also seen multi-contact pins
> that weren't worth spit too.
>
>
>> Does gold make a difference? yes, but not initially. When a pin is
>> initially crimped, the tin/copper (wire) interface
>> is acceptable. But with time , the tin corrodes, whereas the gold (being
>> malleable and inert) maintains a good
>> connection. The fact that time is a factor causes even the best of
>> engineers to overlook the advantages of gold pins.
>>
>
> At least partial agreement here again. I think it's highly application
> dependent. I've found that gold pins and contacts are more reliable long
> term, depending on the environment. I have *not* found any problems with
> the tin contact/wire crimp interface at all. I've seen wires so corroded
> that they were effectively gone, but the wire section of the crimp area was
> still intact. It's pretty much a multi-contact gas tight fit when propoerly
> crimped. If the corrosion is really that bad then I would argue it's a mis-
> application of the connector (and probably the wire harness too) and should
> be re-thought.
>
> Bah, connectors are the devil's spawn anyway. The biggest failure mode of
> electronic assemblies is the mechanical connections regardless how they're
> done. I try to minimize connector usage as much as possible. Sadly, we must
> design things that have to hookup to the outside world and can't avoid them
> entirely...
>
>
Agreed, as are other mechanical devices, such as switches and/or
jumpers. I try my best to avoid
using jumpers. I now include a tiny EEPROM if settings are needed for
anything.
> There was solid analysis done on what was happening to the kk
> connectors, using a laboratory to assist
> us. What was happening was that high current sometimes flowed through
> some of the connector pins. Over time-
> and not much was needed- the springiness of the connector faded due to
> the high current it was handling,
>
What kind of current are you talking about? tens of milliamps? hundreds
of milliamps? amps? tens of amps?
> Most hand tools sold for Molex pins are crap. It has to be a ratcheting
> crimper and it has to have correctly designed dies. Anything else is a toy
> and should be avoided. That's why the typical $20 crimpers are virtually
> always a *bad thing*. If you see a $20 crimper, run for the hills as you
> will have problems with it sooner or later. I normally expect to pay at
> least $50-80 (and sometimes a lot more) for a good quality ratcheting
> crimper. The more obscure the pin you are wanting to crimp, generally the
> more expensive the crimper will be.
>
>
>>For small companies, the solution is to purchase wires with the crimps
>>already installed by hydraulic crimping
>>tools. MANY cable companies offer such crimping services, just call
>>around.
>
The very latest Molex hand crimper is German made and has a calibrated
spring to apply uniform force.(good)
No adjustments , if it doesn't crimp anymore throw it away. (bad)
>
> BTW, there is one MORE source of connector problems: surface-mounted
> connectors. Instead of being thru-hole
> mounted, each post is tacked to a surface pad. These ARE _definitely_
> criminal.
I agree, I've repaired a number of these for people where the solder
joints that held the connector to the pcb fatigued and failed over
time, a failure mode that you just don't ever see with thru-hole. In
fact, I designed this failure mode into a system, where impact that
couldn't be handled by the case flexure was designed to shear the
connector from a plug-in board rather than cause damage to the
motherboard that would have been a much more difficult repair.
I've seen the failures in connectors that didn't have much force at
all applied, so I'm saying that all external interface connectors must
be thruhole.
peter green wrote:
>> There was solid analysis done on what was happening to the kk
>> connectors, using a laboratory to assist
>> us. What was happening was that high current sometimes flowed through
>> some of the connector pins. Over time-
>> and not much was needed- the springiness of the connector faded due to
>> the high current it was handling,
>>
>>
> What kind of current are you talking about? tens of milliamps? hundreds
> of milliamps? amps? tens of amps?
>
Two or more amps.
> Matt Pobursky wrote:
>
> > Most hand tools sold for Molex pins are crap. It
> has to be a ratcheting
> > crimper and it has to have correctly designed
> dies. Anything else is a toy
> > and should be avoided. That's why the typical $20
> crimpers are virtually
> > always a *bad thing*. If you see a $20 crimper,
> run for the hills as you
> > will have problems with it sooner or later. I
> normally expect to pay at
> > least $50-80 (and sometimes a lot more) for a good
> quality ratcheting
> > crimper. The more obscure the pin you are wanting
> to crimp, generally the
> > more expensive the crimper will be.
> >
> >
> >>For small companies, the solution is to purchase
> wires with the crimps
> >>already installed by hydraulic crimping
> >>tools. MANY cable companies offer such crimping
> services, just call
> >>around.
> >
>
> The very latest Molex hand crimper is German made
> and has a calibrated
> spring to apply uniform force.(good)
> No adjustments , if it doesn't crimp anymore throw
> it away. (bad)
>
> Dave
> --
Which model are you refering too?
John
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
> Over time- and not much was needed- the springiness of the
> connector faded due to the high current it was handling,
You mean the connector HEATED enough to un-temper, due to the
current through it?! Sounds to me like that was just the
wrong type of connector to start with (and it seems that
you agree.) (although I suppose "behavior when abused"
still factors into the "goodness" of a connector.)
John Chung wrote:
..
>>The very latest Molex hand crimper is German made
>>and has a calibrated
>>spring to apply uniform force.(good)
>>No adjustments , if it doesn't crimp anymore throw
>>it away. (bad)
>>
>>Dave
>>--
>
> Which model are you refering too?
>
> John
No access to one right now,(poking 'round Mouser..)
should be either 63811-7500 or 63811-2300
D
>> there is one MORE source of connector problems: surface-mounted
>> connectors. Instead of being thru-hole
>> mounted, each post is tacked to a surface pad.
What about the connectors with surface mount pads and plastic
"posts" that mate up with holes? Do the posts provide enough
strain relief ? This seems to be particularly possible with
things like MUSB and flash sockets, where the expected number
of insertions and removals is pretty high compared to other
connectors...
On Sat, 2007-11-10 at 12:52 -0500, David VanHorn wrote:
> >
> > BTW, there is one MORE source of connector problems: surface-mounted
> > connectors. Instead of being thru-hole
> > mounted, each post is tacked to a surface pad. These ARE _definitely_
> > criminal.
>
> I agree, I've repaired a number of these for people where the solder
> joints that held the connector to the pcb fatigued and failed over
> time, a failure mode that you just don't ever see with thru-hole. In
> fact, I designed this failure mode into a system, where impact that
> couldn't be handled by the case flexure was designed to shear the
> connector from a plug-in board rather than cause damage to the
> motherboard that would have been a much more difficult repair.
>
> I've seen the failures in connectors that didn't have much force at
> all applied, so I'm saying that all external interface connectors must
> be thruhole.
What about SMT connectors that have through hole mounting points, either
through hole solder tabs or holes with nuts and bolts holding the
connector to the PCB? Just curious since so many connectors these days
have pitches way to small to do through hole.
> What about SMT connectors that have through hole mounting points, either
> through hole solder tabs or holes with nuts and bolts holding the
> connector to the PCB? Just curious since so many connectors these days
> have pitches way to small to do through hole.
Those I've not had problems with, and I'd call them substantially thruhole.
William "Chops" Westfield wrote:
> On Nov 10, 2007, at 8:40 AM, Bob Axtell wrote:
>
>
>> Over time- and not much was needed- the springiness of the
>> connector faded due to the high current it was handling,
>>
>
> You mean the connector HEATED enough to un-temper, due to the
> current through it?! Sounds to me like that was just the
> wrong type of connector to start with (and it seems that
> you agree.) (although I suppose "behavior when abused"
> still factors into the "goodness" of a connector.)
>
> BillW
>
>
That's about it.
> On Sat, 2007-11-10 at 12:52 -0500, David VanHorn wrote:
>
>>> BTW, there is one MORE source of connector problems: surface-mounted
>>> connectors. Instead of being thru-hole
>>> mounted, each post is tacked to a surface pad. These ARE _definitely_
>>> criminal.
>>>
>> I agree, I've repaired a number of these for people where the solder
>> joints that held the connector to the pcb fatigued and failed over
>> time, a failure mode that you just don't ever see with thru-hole. In
>> fact, I designed this failure mode into a system, where impact that
>> couldn't be handled by the case flexure was designed to shear the
>> connector from a plug-in board rather than cause damage to the
>> motherboard that would have been a much more difficult repair.
>>
>> I've seen the failures in connectors that didn't have much force at
>> all applied, so I'm saying that all external interface connectors must
>> be thruhole.
>>
>
> What about SMT connectors that have through hole mounting points, either
> through hole solder tabs or holes with nuts and bolts holding the
> connector to the PCB? Just curious since so many connectors these days
> have pitches way to small to do through hole.
>
> Thanks, TTYL
>
If you have a way to relieve the pressure of removal then you should be
OK, I think.
windreader.com> wrote:
