CBM edge connectors pitch?

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CBM edge connectors pitch?

silverdr-2
Do we know what is the norm used in the CBM edge connectors? Like the IEEE, USER PORT or CASSETTE?

I found out mentions that it uses a 0.156" pitch. Where the heck does that come from? Nothing "round" in either metric or imperial..

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Re: CBM edge connectors pitch?

Jim Brain
On 10/13/2016 12:31 PM, [hidden email] wrote:
Do we know what is the norm used in the CBM edge connectors? Like the IEEE, USER PORT or CASSETTE?

I found out mentions that it uses a 0.156" pitch. Where the heck does that come from? Nothing "round" in either metric or imperial..


I can confirm it is .156", and I agree it is odd.


But, it was very common in the early 70's.  Lots of stuff was .156"


Your question seems very interesting, I am reposting it to cctalk, as folks on there are usually a fountain of good info, and I suspect someone on there has the true scoop.


Jim




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smf
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Re: CBM edge connectors pitch?

smf
On 13/10/2016 18:38, Jim Brain wrote:
> But, it was very common in the early 70's.  Lots of stuff was .156"

It's common now as well, I'd be interested in the history of that. It's
probably boring, like someone used it for some random reason then
everyone copied it.

It's not just computers that have strange measurements, 2 by fours are
around 1.5 x 3.5 inches (metric 2 by fours are different again).


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Re: CBM edge connectors pitch?

silverdr-2

> On 2016-10-13, at 20:12, smf <[hidden email]> wrote:
>
> On 13/10/2016 18:38, Jim Brain wrote:
>> But, it was very common in the early 70's.  Lots of stuff was .156"
>
> It's common now as well, I'd be interested in the history of that. It's probably boring, like someone used it for some random reason then everyone copied it.

It would also be interesting to know if it's really .156" or this comes from something like .1556847636 rounded to "reasonable" precision?

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Re: CBM edge connectors pitch?

Jim Brain
In reply to this post by smf
On 10/13/2016 1:12 PM, smf wrote:
On 13/10/2016 18:38, Jim Brain wrote:
But, it was very common in the early 70's.  Lots of stuff was .156"

It's common now as well, I'd be interested in the history of that. It's probably boring, like someone used it for some random reason then everyone copied it.

It's not just computers that have strange measurements, 2 by fours are around 1.5 x 3.5 inches (metric 2 by fours are different again).


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Not to get off-topic long term, but I completely understand 2x4s.


http://www.fpl.fs.fed.us/documnts/misc/miscpub_6409.pdf


Short answer:

They were originally 2" by 4", but were rough.  "Dressing" them to finished lumber brought down the size, and the demands for dressed lumber, at consistent sizes, shipped via rail, forced the 2x4 to become 1.5" by 3.5"

At one point, the size was 1 5/8 * 3 5/8, but it was harder to calculate, so 1.5 by 3.5 became the norm.

Of course, that's in horrid imperial measurements.  No idea on metric.

Jim
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Re: CBM edge connectors pitch?

Justin-2
Jim, the metric system was invented because Europeans can't do fractional math.

Justin

On Oct 13, 2016, at 18:57, Jim Brain <[hidden email]> wrote:

On 10/13/2016 1:12 PM, smf wrote:
On 13/10/2016 18:38, Jim Brain wrote:
But, it was very common in the early 70's.  Lots of stuff was .156"

It's common now as well, I'd be interested in the history of that. It's probably boring, like someone used it for some random reason then everyone copied it.

It's not just computers that have strange measurements, 2 by fours are around 1.5 x 3.5 inches (metric 2 by fours are different again).


      Message was sent through the cbm-hackers mailing list

Not to get off-topic long term, but I completely understand 2x4s.


http://www.fpl.fs.fed.us/documnts/misc/miscpub_6409.pdf


Short answer:

They were originally 2" by 4", but were rough.  "Dressing" them to finished lumber brought down the size, and the demands for dressed lumber, at consistent sizes, shipped via rail, forced the 2x4 to become 1.5" by 3.5"

At one point, the size was 1 5/8 * 3 5/8, but it was harder to calculate, so 1.5 by 3.5 became the norm.

Of course, that's in horrid imperial measurements.  No idea on metric.

Jim
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Re: CBM edge connectors pitch?

Jim Brain
On 10/13/2016 7:09 PM, Justin Cordesman wrote:
> Jim, the metric system was invented because Europeans can't do
> fractional math.
Oooh, let me go get some popcorn.  this gun' be good...

Let's see, it's around midnight there.  Give it a few hours... :-)

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Re: CBM edge connectors pitch?

Clockmeister
In reply to this post by Justin-2


On 14/10/2016 8:09 AM, Justin Cordesman wrote:
> Jim, the metric system was invented because Europeans can't do
> fractional math.
>


Metric is a rational system. Given that one of the US presidential
candidates is Donald Trump, It's understood that Americans have a
natural aversion to anything that is rational.

(there you go Jim :-)







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Re: CBM edge connectors pitch?

Anders Carlsson
Clockmeister wrote:

> one of the US presidential candidates is Donald Trump

I'm sure Donald has something that is 0.156" tall, I just don't know which
part of him. ;-)

Best regards

Anders Carlsson


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Re: CBM edge connectors pitch?

smf
In reply to this post by Justin-2
On 14/10/2016 01:09, Justin Cordesman wrote:
> Jim, the metric system was invented because Europeans can't do fractional math.

It all started when the Coinage Act of 1792 created the US dollar. Who
can't do fractional math?

And let's not go into why American English was invented....

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Re: CBM edge connectors pitch?

smf
In reply to this post by Anders Carlsson
On 14/10/2016 08:02, Anders Carlsson wrote:
> I'm sure Donald has something that is 0.156" tall, I just don't know
> which part of him. ;-)

His little tiny baby pouting mouth?


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Re: CBM edge connectors pitch?

silverdr-2
In reply to this post by Clockmeister

> On 2016-10-14, at 02:59, Clockmeister <[hidden email]> wrote:
>
> On 14/10/2016 8:09 AM, Justin Cordesman wrote:
>> Jim, the metric system was invented because Europeans can't do fractional math.
>
> Metric is a rational system. Given that one of the US presidential candidates is Donald Trump, It's understood that Americans have a natural aversion to anything that is rational.

Given the rational alternative of a slimy crook, the irrational choice seems so much more appealing. Vote for Trump, Americans.

There you go too :-P
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Re: CBM edge connectors pitch?

smf
On 14/10/2016 11:16, [hidden email] wrote:
> Given the rational alternative of a slimy crook, the irrational choice seems so much more appealing. Vote for Trump, Americans.
>
> There you go too :-P

 From the outside, it appears that the slimy crook is Trump (*). He's
just got the same reality distortion field as Steve Jobs had.

Which is fine, as long as the reality distortion works on everyone. But
it doesn't even work on all the US population, it works less on people
outside the US.

(*) The only thing Hilary appears to be guilty of is having an email
server (like other politicians had) and deleted mail (which most people
do). While Trump has run some seriously fraudulent enterprises and
"cleverly" avoided paying any taxes (which means he thinks anyone who
pays taxes is stupid).


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Re: CBM edge connectors pitch?

silverdr-2

> On 2016-10-14, at 12:28, smf <[hidden email]> wrote:
>
> On 14/10/2016 11:16, [hidden email] wrote:
>> Given the rational alternative of a slimy crook, the irrational choice seems so much more appealing. Vote for Trump, Americans.
>>
>> There you go too :-P
>
> From the outside, [...],

No - Let's not get into this anymore ;-) We still have the interesting history of 0.1556873546 inch connector pitch to uncover and I wonder what Jim can bring to the table from the other circle of his.

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SD!


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Re: CBM edge connectors pitch?

Marko Mäkelä
In reply to this post by smf
On Fri, Oct 14, 2016 at 11:28:12AM +0100, smf wrote:
>On 14/10/2016 11:16, [hidden email] wrote:
>>Given the rational alternative of a slimy crook, the irrational choice
>>seems so much more appealing. Vote for Trump, Americans.
>>
>>There you go too :-P
>
>From the outside, it appears that the slimy crook is Trump (*). He's
>just got the same reality distortion field as Steve Jobs had.

Isn't any seasoned politician essentially a liar? Telling what they
think the audience wants to hear, instead of telling what they think,
and so on. Some only are better (or more consistent) at it than others.  
At a suitably high level of abstraction, both alternatives are slimy
crooks. :)

>Which is fine, as long as the reality distortion works on everyone.  
>But it doesn't even work on all the US population, it works less on
>people outside the US.

This reminds me of the saying that is sometimes attributed to Abraham
Lincoln but apparently has European origins, saying that you can fool
some for all the time, all for some time, but not all for all the time:

http://quoteinvestigator.com/2013/12/11/cannot-fool/

That said, back on topic: I wonder if it actually is 1.559" = 39.5986mm
nowadays.

        Marko

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Re: CBM edge connectors pitch?

Anders Carlsson
In reply to this post by silverdr-2

silverdr wrote:

We still have the interesting history of 0.1556873546 inch connector pitch to uncover

To begin with, I found this document from September 1970. On page 31, the system is specified with 0.156" spacing on the edge connectors.

https://cds.cern.ch/record/1249526/files/ISR-70-40.pdf

Here are some screws (!) where 5/32 and 0.156 are used. If the number actually is a truncated 0.15625 inch, it isn't that odd anymore but also the 3.96 mm spacing should rather be rounded to 3.97 mm.

http://www1.mscdirect.com/pdf/fasteners/socketheadcapscrews.pdf

Of course the question remains when the 5/32 or 0.156" was introduced for spacing in electronics. I would assume during the 1960s.

Best regards

Anders Carlsson

 

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Re: CBM edge connectors pitch?

Jim Brain
In reply to this post by silverdr-2
On 10/14/2016 5:52 AM, [hidden email] wrote:
>> On 2016-10-14, at 12:28, smf <[hidden email]> wrote:
>>
>> On 14/10/2016 11:16, [hidden email] wrote:
>>> Given the rational alternative of a slimy crook, the irrational choice seems so much more appealing. Vote for Trump, Americans.
>>>
>>> There you go too :-P
>>  From the outside, [...],
> No - Let's not get into this anymore ;-)
Yeah, I feel bad, as I think I started this, I am a mailing list
moderator (on a different list), and I know politics in a technology
list is never going to add value.  I should have probably self censored
my posts :-)

Suffice it to say that I live in the US, and I am generally proud of my
country, but the recent political landscape exhibits a distinct election
process design "corner case" that many would consider an error.  How to
patch a running system, though, is a tough thing to determine.
> We still have the interesting history of 0.1556873546 inch connector pitch to uncover and I wonder what Jim can bring to the table from the other circle of his.
>
Well, I have good news and bad news.  As some have noted here, it
appears to be a mutation of 5/32", but folks are still trying to
determine the significance of 5/32".  I mean, 1/8" was in general use as
a measurement (earphone connector) in this timeframe, so I would expect
.125" to be more realistic.

But, I continue to ask.

Jim


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[hidden email]
www.jbrain.com


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Re: CBM edge connectors pitch?

William Levak
In reply to this post by Marko Mäkelä
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Re: CBM edge connectors pitch?

Greg King-3
In reply to this post by Jim Brain
On 2016-10-14 1:33 PM, Jim Brain wrote:
>
> Well, I have good news and bad news.  As some have noted here, it
> appears to be a mutation of 5/32"; but, folks are still trying to
> determine the significance of 5/32".  I mean, 1/8" was in general use as
> a measurement (earphone connector) in that timeframe; so, I would expect
> .125" to be more realistic.  But, I continue to ask.

Maybe, it was economics.  Manufacturers already had tools to handle
screw pitches.  Maybe, they adapted them to manufacturing electronic
connectors, instead of spending (more) money to create new tools (with
new sizes).

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