wrote:
On Sun, 24 Apr 2016 19:57:48 +0000 (UTC), Cydrome Leader
wrote:

wrote:
On Sunday, April 24, 2016 at 8:49:03 AM UTC-4, Ed Huntress wrote:


Anyway, the point is that no one here is old enough to remember the
use of "mil" for thousandths of an inch, but some of us who were
deeply involved in metalworking history have seen it used a lot in the
deep past.


--
Ed Huntress




Sorry about that, but I and Cydrome Leader both remember mil as being the same as a thousandth. We are not all as young as you.

I've been trying to figure out where I learned mil from. While I do have
an electronic-ish background, it's not really a unit you'd use when
repairing something. It's likely from an an older designer or engineer
friend.

Circular mils are still common enough when it comes to electrical guages,
such as a 500MCM cable, even though that's sort of a weird unit- "thousand
circular mils." Pretty sure that's the same as a 1/2" copper rod.


You sure about that???
Comes out to more like a 3/4 inch copper rod (actually 0.8" diameter)

Not completely sure at this point- and it looks like there are three ideas
as to what 500MCM cable is equivalent to if it was just a rod. May have to
look this one up.

On 24-Apr-16 9:10 AM, DoN. Nichols wrote:
On 2016-04-23, Gunner Asch wrote:
On Fri, 22 Apr 2016 16:27:05 +0000 (UTC), Cydrome Leader
wrote:

I indicated 3/8" barstock to "close enough" of about 3 mils in a 3 jaw,
centerdrilled and used a livecenter.

3 mils????

Common phrase in dimensioning electronics layouts and some other
fields. one "mil" is 0.001". (We are more likely to call it a "thou".
:-) Just depends on in which field you have worked in the past.

Enjoy,
DoN.




Very common in countries that use the metric system , 1 Mil = 1 millimeter.

On Tue, 26 Apr 2016 08:16:19 +0930, Bluey69
wrote:

On 24-Apr-16 9:10 AM, DoN. Nichols wrote:
On 2016-04-23, Gunner Asch wrote:
On Fri, 22 Apr 2016 16:27:05 +0000 (UTC), Cydrome Leader
wrote:

I indicated 3/8" barstock to "close enough" of about 3 mils in a 3 jaw,
centerdrilled and used a livecenter.

3 mils????

Common phrase in dimensioning electronics layouts and some other
fields. one "mil" is 0.001". (We are more likely to call it a "thou".
:-) Just depends on in which field you have worked in the past.

Enjoy,
DoN.




Very common in countries that use the metric system , 1 Mil = 1 millimeter.

Which is 39.37 thousandths of an inch.

On Mon, 25 Apr 2016 16:00:39 -0700, Gunner Asch
wrote:

On Tue, 26 Apr 2016 08:16:19 +0930, Bluey69
wrote:

On 24-Apr-16 9:10 AM, DoN. Nichols wrote:
On 2016-04-23, Gunner Asch wrote:
On Fri, 22 Apr 2016 16:27:05 +0000 (UTC), Cydrome Leader
wrote:

I indicated 3/8" barstock to "close enough" of about 3 mils in a 3 jaw,
centerdrilled and used a livecenter.

3 mils????

Common phrase in dimensioning electronics layouts and some other
fields. one "mil" is 0.001". (We are more likely to call it a "thou".
:-) Just depends on in which field you have worked in the past.

Enjoy,
DoN.




Very common in countries that use the metric system , 1 Mil = 1 millimeter.

Which is 39.37 thousandths of an inch.

Plastic bags and sheeting are still sold in mils. 2 mil = 0.002"

--
If you want to make your dreams come true,
the first thing you have to do is wake up!
--anon

On Mon, 25 Apr 2016 08:26:16 -0400, Leon Fisk
wrote:

On Sun, 24 Apr 2016 21:50:30 -0400
Ed Huntress wrote:

On Mon, 25 Apr 2016 08:44:12 +0700, John B.
wrote:

Interestingly he tried a number of alloys for his counterfeit quarters
and the Coke Machine rejected them all :-)

On Sun, 24 Apr 2016 09:53:34 -0400, Ed Huntress
wrote:

He was too early. Today, he probably could get away with any scrap
metal. g

The machines I looked at several years ago only took bills. I guess
they have them now that you can pay with your smart phone...

A different kind of counterfeiting required to bypass them

30+ years ago I was takeing a "night school" Saturday morning class at
the local community college. Since the winter class was held outdoors,
we were happy to indulge in the mid class coffee break in the
automated caffeteria. One Saturday, the coffee machine refused to
co-operate. After I "thumped" it a couple times, everyone had a free
coffee an I had over $5.00 in leftover coins!
---

Gerry :-)}
London,Canada

On Mon, 25 Apr 2016 09:47:39 -0400, Ed Huntress
wrote:

On Mon, 25 Apr 2016 09:35:47 -0400, Leon Fisk
wrote:

On Mon, 25 Apr 2016 08:44:12 +0700
John B. wrote:

snip
Interestingly he tried a number of alloys for his counterfeit quarters
and the Coke Machine rejected them all :-)

Mid 70's... one of my fellow shop class students figured out that he
could re-size pennies using the 1 inch vertical belt sander. Schools
vending machines took them as dimes. He was caught a short time later
working at the belt sander

Imagine doing time in a federal prison for counterfeiting dimes. g
We used to dip clean pennies in mercury and pass them as dimes with
local merchants
---

Gerry :-)}
London,Canada

On Mon, 25 Apr 2016 19:55:41 -0400, wrote:

On Mon, 25 Apr 2016 09:47:39 -0400, Ed Huntress
wrote:

On Mon, 25 Apr 2016 09:35:47 -0400, Leon Fisk
wrote:

On Mon, 25 Apr 2016 08:44:12 +0700
John B. wrote:

snip
Interestingly he tried a number of alloys for his counterfeit quarters
and the Coke Machine rejected them all :-)

Mid 70's... one of my fellow shop class students figured out that he
could re-size pennies using the 1 inch vertical belt sander. Schools
vending machines took them as dimes. He was caught a short time later
working at the belt sander

Imagine doing time in a federal prison for counterfeiting dimes. g
We used to dip clean pennies in mercury and pass them as dimes with
local merchants
---

Gerry :-)}
London,Canada

Oh, right...you're a Canadian. They had to put facets on your nickels
to keep you from shaving them on those long winter nights. g!

--
Ed Huntress

On Mon, 25 Apr 2016 08:48:03 -0400, Ed Huntress
wrote:

On Mon, 25 Apr 2016 19:38:27 +0700, John B.
wrote:

On Sun, 24 Apr 2016 21:50:30 -0400, Ed Huntress
wrote:

On Mon, 25 Apr 2016 08:44:12 +0700, John B.
wrote:

On Sun, 24 Apr 2016 09:53:34 -0400, Ed Huntress
wrote:

On Sun, 24 Apr 2016 20:12:37 +0700, John B.
wrote:

On Sun, 24 Apr 2016 08:48:57 -0400, Ed Huntress
wrote:

On Sun, 24 Apr 2016 18:21:21 +0700, John B.
wrote:

On Sun, 24 Apr 2016 06:43:15 -0400, Ed Huntress
wrote:

On Sun, 24 Apr 2016 14:21:47 +0700, Good Soldier Schweik
wrote:

On Sat, 23 Apr 2016 20:00:29 -0700, Gunner Asch
wrote:

On Sat, 23 Apr 2016 23:23:18 +0000 (UTC), Cydrome Leader
wrote:

Gunner Asch wrote:
On Fri, 22 Apr 2016 16:27:05 +0000 (UTC), Cydrome Leader
wrote:

I indicated 3/8" barstock to "close enough" of about 3 mils in a 3 jaw,
centerdrilled and used a livecenter.

3 mils????

0.003"

Oh..you mean 3 thousandths. NOBODY says 3 mils when machining..least
not in the US.

Only in plastic sheet making will you find it..and thats not
machining..thats extruding

Slang would be 3/1000s, 3k, an RCH, etc etc


I hate to agree with you but I never heard the term "mil" until very
recently and I worked in and around the business since I was in High
School. It was always 3 thousandths (.003) or 3 tenths (.0003) for
smaller dimensions.

Before the late 1930s, "mil" was used commonly in machining, too.


Well, I wasn't around the shops in the "late 1930's" :-)

But I did for a couple of weeks run a lathe that the cross slide was
calibrated in 1/128th of an inch. The owner of the shop reckoned it
dated from "Civil War Days".

When they're that old, you should sell them to interior decorators for
use as foliage planters. They look nice with a Wandering Jew twined
around the bedways, standing between a miniature palm and a ficus
tree. d8-)

Well, this was when I was in High School and the shop was at least 2nd
generation in the same building. It was owned and operated by two
bachelor brothers who didn't talk to each other. The entire shop
except for some bench grinders operated from a single electric motor
"out back" driving an overhead shaft system. Strangely I don't
remember thinking it was an odd place to work :-)

One of the brothers had an absolutely like new Henderson 4 cylinder
motorcycle that he used to ride to work occasionally which certainly
was interesting.

As a summer hire apprentice I wasn't doing any high tech stuff, they
had me making nuts on the old lathe. Even then, making 50 cents an
hour, I can't see how the finances worked. 12 ft of hex stock in an
antique lathe, Drill, tap, part off, advance the stock a bit and do it
again. Sort of a human screw machine :-)

At least he didn't have you start with round bar stock...


But they paid every Friday afternoon at quitting time. Cash in the
hand.

When I hear stories like that, I wonder how the United States, and the
West in general, ever managed to produce anything that anyone could
afford.

Just before wire EDM came into use, I started covering tool and
diemaking, and visited a lot of t&d shops. I watched diemakers rough
out blanking dies with a bandsaw, breaking the blade, threading it
through the work (they milled out a really rough hole first, but it
usually was nowhere near the final size), and then re-welding the
blade back together. Then they'd break the blade to remove the die
from the saw, and they'd go to work with diemaker's chisels, cutting
close to the line and chiseling in some die relief. Then, possibly, on
to the die-filer. Next, hand-filing with files down to jeweler-file
size. After that, the die would go out for heat-treating.


When I was at Edwards AFB they had an "Electric Spark Machine". I was
there for about a year and saw it used just once. A guy made a set of
dies to punch out counterfeit quarters for the Coke Machine.

I'm curious -- what year was that?


It must have been in the mid 1960's.

Ah, OK, that fits. Sinker-type EDMs were pretty capable by then, and
you could use a quarter, say, as an electrode, to burn the end of a
punch or die.

But I think you'd go through a lot of quarters doing it.
Tungsten-silver was a premium electrode material, but I think that
plain silver would melt off pretty quickly.


Good Lord! Fifty years ago? I can just barely remember the incident,
the details are gone for ever :-)


They also had a "tape controlled" machine there that would do things
automatically. It could even change tools, or so I was told. One guy
had been to school on the control system but it was never used while I
was there.

I did ask the guy how it worked and it used a punched tape like a
telex machine. The left column was, say longitudinal travel, and one
punch was one increment of movement.

Um...that's how I learned lathe programming. We had a Sheldon 1710H
controlled by a Bendix 5 NC, and a teletypewriter to key in and punch
the paper tape. I could program straight cylinders and tapers, and
face them off, IIRC. g I never did any actual work with it; the real
machinists wanted to play with it and hogged the keyboard.

For anything complex, we used a telephone-connected time-sharing
system that did the programming by computer.
--

Cheers,

John B.

On Mon, 25 Apr 2016 09:54:34 -0400, Leon Fisk
wrote:

On Mon, 25 Apr 2016 09:47:39 -0400
Ed Huntress wrote:

On Mon, 25 Apr 2016 09:35:47 -0400, Leon Fisk
wrote:

On Mon, 25 Apr 2016 08:44:12 +0700
John B. wrote:

snip
[...]

Mid 70's... one of my fellow shop class students figured out that he
could re-size pennies using the 1 inch vertical belt sander. Schools
vending machines took them as dimes. He was caught a short time later
working at the belt sander

Imagine doing time in a federal prison for counterfeiting dimes. g

After reading John's story I wonder if the pennies material helped it
to be accepted. Some of those machines had pretty innovative means of
detecting real coins. The thing that tripped the kid up was using the
schools shop equipment. If he could have done the work elsewhere it
would have taken a lot longer to catch him.

At another base one of the guys tried turning coin sized blanks for
the Coke Machine. It didn't work either but somehow one of the
machined blanks got stuck in the machine and the Coke Machine Guy went
to the Squadron Commander and a great investigation ensued... "My guy
made a fake coin" Nah, couldn't be, none of them drink Coke".

But it did appear that a Coke machine was a bit "smarter then the
average bear", to paraphrase Pooh.

A far better scheme was discovered by "one of the guys" while TDY to
Okinawa to support the "Black Birds". In wandering around he
discovered that the Jet Engine Shop had bins of some sort of "bronze"
nuts that could be bored out to finger size and when machined and
polished a bit looked surprisingly like a gold ring. Subsequently he
discovered that the "ladies" in the pubs would trade their services
for gold rings.

He said that if he had any more spare time to make rings he probably
would have "died in a foreign land" :-)
--

Cheers,

John B.

On 2016-04-24, Ed Huntress wrote:
On Sun, 24 Apr 2016 18:21:21 +0700, John B.
wrote:

[ ... ]

Anyway, the point is that no one here is old enough to remember the
use of "mil" for thousandths of an inch, but some of us who were
deeply involved in metalworking history have seen it used a lot in the
deep past.

Depends. Back as late as the 1970s, I would commonly see the
term "mil" used in integrated circuit data sheets -- for things like the
spacing between pins on a given side (typically 100 mils), and the
separation between two rows of pins (for common TTL ICs, typically 300
mils -- though some were larger, 400 mils, 600 mils and such). The same
units were used for the dimensions of the bodies of the chips, between
the pins, too. So, the term stuck around for a while longer in certain
industries.

Now -- the surface mount chips -- with rows of ribbon leads
soldered to a single surface of the board were 50 mil centers back then,
though smaller now, I believe.

I don't have any recent data sheets ready to hand, so they may
have changed since then.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

Coming from Semi on the last three jobs - 10 years ago ...

The BGA ball grid arrays were metric. And some of the other Modern
forms of surface mount.

Science and Engineering was metric all along, just took some time for
the general industry to go that way.

The older stuff was designed by Fairchild and TI and later EIA and JEDEC
who created specks on the actual leadframe and therefore pinouts.
Yes RCA and Harris and ..... created stuff as they needed and were all
brought in to have common pinouts, form and function. Competition was
not part of the scene, we were design engineers and loved our jobs.

I was a EIA/JEDEC member Specs or 4 companies, DRAMS, SD, DD, DIMM SoDIM
SIM and Sram and packaging and motherboards. I was a busy guy in a
week or two during JEDEC meetings.

JEDEC was the old name but the group went International in nature.

It was nice, I had friends in dozen or more companies.
We all assigned each other tasks to get done to complete specifications
on this or that.

Martin

On 4/26/2016 8:44 PM, DoN. Nichols wrote:
On 2016-04-24, Ed Huntress wrote:
On Sun, 24 Apr 2016 18:21:21 +0700, John B.
wrote:

[ ... ]

Anyway, the point is that no one here is old enough to remember the
use of "mil" for thousandths of an inch, but some of us who were
deeply involved in metalworking history have seen it used a lot in the
deep past.

Depends. Back as late as the 1970s, I would commonly see the
term "mil" used in integrated circuit data sheets -- for things like the
spacing between pins on a given side (typically 100 mils), and the
separation between two rows of pins (for common TTL ICs, typically 300
mils -- though some were larger, 400 mils, 600 mils and such). The same
units were used for the dimensions of the bodies of the chips, between
the pins, too. So, the term stuck around for a while longer in certain
industries.

Now -- the surface mount chips -- with rows of ribbon leads
soldered to a single surface of the board were 50 mil centers back then,
though smaller now, I believe.

I don't have any recent data sheets ready to hand, so they may
have changed since then.

Enjoy,
DoN.