I just found out JO bloks increase in size over time naturally?????
Also they expand .0000115 * Length for every 1.8 dgrees F above 68 degrees.
They are calibrated with grren light due to its short wavelength.
If only i could find out what wringing means, how its done.

Any who are interested check out
http://ts.nist.gov/ts/htdocs/230/233...pubs/MN180.pdf
for THE nist gage block manual

"Ben" wrote in message
. ..
I just found out JO bloks increase in size over time naturally?????
Also they expand .0000115 * Length for every 1.8 dgrees F above 68
degrees.
They are calibrated with grren light due to its short wavelength.
If only i could find out what wringing means, how its done.

If you're interested in a short article I wrote about wringing a couple of
years ago -- based on an interview with NIST's top gage-block guy -- I could
send it to you. Or I could post it here, if a few others wanted to see it. I
think it's only around 600 words.

Ed Huntress

Ed:

Please post it here or to the dropbox. I would be interested in
having my students read it.

Errol Groff




On Sun, 30 Nov 2003 22:12:42 GMT, "Ed Huntress"
wrote:

"Ben" wrote in message
...
I just found out JO bloks increase in size over time naturally?????
Also they expand .0000115 * Length for every 1.8 dgrees F above 68
degrees.
They are calibrated with grren light due to its short wavelength.
If only i could find out what wringing means, how its done.

If you're interested in a short article I wrote about wringing a couple of
years ago -- based on an interview with NIST's top gage-block guy -- I could
send it to you. Or I could post it here, if a few others wanted to see it. I
think it's only around 600 words.

Ed Huntress

"Errol Groff" wrote in message
...

Ed:

Please post it here or to the dropbox. I would be interested in
having my students read it.

Errol Groff

Oh, jeez, Errol, I just remembered -- I've got that book here all wrapped
for you, and I forgot to send it! Man, I'm losing my mind here. I'm awfully
sorry about that. I just put it on the dining room table so I'll remember it
at breakfast tomorrow and take it down to the UPS office. I hate getting
old...

As for the article, it's short enough that maybe people won't mind it if I
put it here. If anybody objects then they can yell at me like we yell at
Gunner. g This is about WHY they wring (although it doesn't answer the
question very well, it appears to be as well as it can be answered), not how
to wring them. I assume you teach them that:

==================================================

Machine Shop Guide
March, 2001 Issue

[Department]

How It's Done

By Ed Huntress, Senior Editor

[Headline]

Why Do Gage Blocks Wring?

[text]

Wringing gage blocks is such a commonplace that the phenomenon has lost its
parlor-trick appeal, as in, "Watch as I make these simple blocks of steel
defy gravity, without benefit of magnetism, adhesives, or
sleight-of-hand..." It's in the low tier of tricks, a notch below gyroscopes
and Jacob's Ladders. But for all science knows it could be sleight-of-hand,
because the time-honored theories about why these flat blocks stick together
have been debunked.

One would think that scanning electron microscopes and high-velocity
particle accelerators, at least, would have cleared it up. Asked why gage
blocks wring, really, physicist Ted Doiron says, "Theories are all you'll
get. There probably are several phenomena going on. It's not a case of
squeezing out the air, because the resulting pressure holding them together
couldn't be more than atmospheric (14.7 lb./sq. in.), and we know that the
force can be greater than that in practice. It isn't just moisture, because
they've been wrung in low-humidity boxes with virtually no water vapor in
the air. And it isn't just physical bonding, because they can be taken
apart. In practice, it may be some molecular bonding, some water-vapor, who
knows what-all."

One wishes for a clear, singular explanation. If there was one to be had,
Doiron would know it, as the metrologist and physicist at the National
Institute for Standards and Technology (NIST, Gaithersburg, MD) who's job,
as he puts it, includes reading every paper ever published about gage
blocks. "Every country has one person who has to read them all. I'm it for
the US," he says.

If one has to spend a lot of time with gage blocks, a bit of mystery may be
welcome. Much of the work Doiron's department does involves uncovering those
mysteries that can be resolved. Their resolution skills are considerable.
"Gage blocks don't wring consistently," says Doiron. "I've had four of my
technicians wring down a set, and there was a height variation in the stacks
of half of a microinch. One guy wrings them down a microinch smaller than
the sum of their lengths would normally indicate."

When you work in half-microinches, your view of the world changes. "Gage
blocks really aren't flat," Doiron says. "The faces of some are bell-shaped,
others are wavy, others are this or that. Both ends can be out of flat by a
fair amount -- as much as four microinches. Wring two together, then rotate
one 180 degrees and wring them again...they'll wring differently. They can
vary by a half-microinch, just by rotating them. At international metrology
conferences they've had us wring blocks at opposite ends, and we get a
variation of a half-microinch that way, too." We hadn't the temerity to ask
if that was part of the conference proceeding or part of the entertainment.

Wringing gage blocks against an optical flat reveals variations in the gap
that depend on how you wring them together. Nothing is ever perfectly clean,
and it's difficult to get a strain-free wring. You can see fringes, says
Doiron, that sometimes disappear if you tap the end of the block with a
hammer, or even with a pencil. At this scale, everything seems a bit
rubbery.

"At the microinch level, we run into limits of gage-block accuracy and we're
well into the range of wringing variability. We've had numbers of cases of
different gage-block companies disagreeing on the height of a given
three-block stack. And they're all right. Wringing and other variables, all
within accepted practice, can cause a variation of three or four microinches
in that three-block stack."

When one gets serious, he uses an interferometer to measure height and he
doesn't wring the stack. The methods NIST and other top-end certifying
organizations use involve measuring from a point at the top of the stack to
the flat surface they rest on. "I'd like to change that to point-to-point,"
says Doiron, "but the equipment to measure that way doesn't exist."

Doiron points out that gage blocks can be made flatter and more parallel
than they are. "But who needs a microinch?," he asks. To which we respond,
hardly anyone. But we're glad there are people like Ted Doiron and his
department who can answer the need if it should arise.

--end--

Ed:

No problem at al about the book. Tell the truth I had forgotten about
it myself. Now that you mention it though I am looking forward to
looking it over.

Errol Groff
Instructor, Machine Tool Department
H.H. Ellis Tech
613 Upper Maple Street
Danielson, CT 06239

860 774 8511 x1811

http://pages.cthome.net/errol.groff/

http://newenglandmodelengineeringsociety.org/



On Sun, 30 Nov 2003 23:19:59 GMT, "Ed Huntress"
wrote:

"Errol Groff" wrote in message
.. .

Ed:

Please post it here or to the dropbox. I would be interested in
having my students read it.

Errol Groff

Oh, jeez, Errol, I just remembered -- I've got that book here all wrapped
for you, and I forgot to send it! Man, I'm losing my mind here. I'm awfully
sorry about that. I just put it on the dining room table so I'll remember it
at breakfast tomorrow and take it down to the UPS office. I hate getting
old...

As for the article, it's short enough that maybe people won't mind it if I
put it here. If anybody objects then they can yell at me like we yell at
Gunner. g This is about WHY they wring (although it doesn't answer the
question very well, it appears to be as well as it can be answered), not how
to wring them. I assume you teach them that:

================================================= =

Machine Shop Guide
March, 2001 Issue

[Department]

How It's Done

By Ed Huntress, Senior Editor

[Headline]

Why Do Gage Blocks Wring?

[text]

Wringing gage blocks is such a commonplace that the phenomenon has lost its
parlor-trick appeal, as in, "Watch as I make these simple blocks of steel
defy gravity, without benefit of magnetism, adhesives, or
sleight-of-hand..." It's in the low tier of tricks, a notch below gyroscopes
and Jacob's Ladders. But for all science knows it could be sleight-of-hand,
because the time-honored theories about why these flat blocks stick together
have been debunked.

One would think that scanning electron microscopes and high-velocity
particle accelerators, at least, would have cleared it up. Asked why gage
blocks wring, really, physicist Ted Doiron says, "Theories are all you'll
get. There probably are several phenomena going on. It's not a case of
squeezing out the air, because the resulting pressure holding them together
couldn't be more than atmospheric (14.7 lb./sq. in.), and we know that the
force can be greater than that in practice. It isn't just moisture, because
they've been wrung in low-humidity boxes with virtually no water vapor in
the air. And it isn't just physical bonding, because they can be taken
apart. In practice, it may be some molecular bonding, some water-vapor, who
knows what-all."

One wishes for a clear, singular explanation. If there was one to be had,
Doiron would know it, as the metrologist and physicist at the National
Institute for Standards and Technology (NIST, Gaithersburg, MD) who's job,
as he puts it, includes reading every paper ever published about gage
blocks. "Every country has one person who has to read them all. I'm it for
the US," he says.

If one has to spend a lot of time with gage blocks, a bit of mystery may be
welcome. Much of the work Doiron's department does involves uncovering those
mysteries that can be resolved. Their resolution skills are considerable.
"Gage blocks don't wring consistently," says Doiron. "I've had four of my
technicians wring down a set, and there was a height variation in the stacks
of half of a microinch. One guy wrings them down a microinch smaller than
the sum of their lengths would normally indicate."

When you work in half-microinches, your view of the world changes. "Gage
blocks really aren't flat," Doiron says. "The faces of some are bell-shaped,
others are wavy, others are this or that. Both ends can be out of flat by a
fair amount -- as much as four microinches. Wring two together, then rotate
one 180 degrees and wring them again...they'll wring differently. They can
vary by a half-microinch, just by rotating them. At international metrology
conferences they've had us wring blocks at opposite ends, and we get a
variation of a half-microinch that way, too." We hadn't the temerity to ask
if that was part of the conference proceeding or part of the entertainment.

Wringing gage blocks against an optical flat reveals variations in the gap
that depend on how you wring them together. Nothing is ever perfectly clean,
and it's difficult to get a strain-free wring. You can see fringes, says
Doiron, that sometimes disappear if you tap the end of the block with a
hammer, or even with a pencil. At this scale, everything seems a bit
rubbery.

"At the microinch level, we run into limits of gage-block accuracy and we're
well into the range of wringing variability. We've had numbers of cases of
different gage-block companies disagreeing on the height of a given
three-block stack. And they're all right. Wringing and other variables, all
within accepted practice, can cause a variation of three or four microinches
in that three-block stack."

When one gets serious, he uses an interferometer to measure height and he
doesn't wring the stack. The methods NIST and other top-end certifying
organizations use involve measuring from a point at the top of the stack to
the flat surface they rest on. "I'd like to change that to point-to-point,"
says Doiron, "but the equipment to measure that way doesn't exist."

Doiron points out that gage blocks can be made flatter and more parallel
than they are. "But who needs a microinch?," he asks. To which we respond,
hardly anyone. But we're glad there are people like Ted Doiron and his
department who can answer the need if it should arise.

--end--