What's the difference between +- .001 and +- 10 minutes?

There is no comparison. One's a linear measure and the other is an angular
measure.

"tommyboy" wrote in message
...
What's the difference between +- .001 and +- 10 minutes?

"tommyboy" wrote in message
...
What's the difference between +- .001 and +- 10 minutes?

..001 is the measurement
10 minutes is the time needed to find the damned caliper to check the
measurement.

The difference is that if you don't find it in 10 minutes, you use the block
anyway.

"Edwin Pawlowski" wrote in message
t...

"tommyboy" wrote in message
...
What's the difference between +- .001 and +- 10 minutes?

.001 is the measurement
10 minutes is the time needed to find the damned caliper to check the
measurement.

The difference is that if you don't find it in 10 minutes, you use the
block
anyway.

tommyboy wrote:

What's the difference between +- .001 and +- 10 minutes?

One's the accuracy in height (a length), the other is the accuracy in
levelness (an angle)

In a woodworking group, both are far bettter than you care about.

under the heading:
How do you convert to Degrees from Degrees: Minutes:Seconds on the site,
http://jwocky.gsfc.nasa.gov/teacher/latlonarchive.html

There is a whole world of surface symbols and terminology for drawings and
specs, generally not needed in ww, and angle is a part of it. But this is
just a format. Although this site may be showing a sphere, the calculation
is the same, and the format is for angle, 360 for a full rev. 359 degrees,
59`, 59`` the next lower, though can`t say about decimals or further.

As a set of parameters it may be x dim at y angle, a parallax parameter
restriction, with a reference point(s), but my bet is its a screw up.



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If you run into symbols try googling "GD&T symbols". Geometric dimentioning
and tolerancing. These symbols are the words of a language. Filled in with
actual values they can be combined in a bewildering combination of meanings.

http://www.tec-ease.com/gdt-terms.htm

For instance how 'straight is the cutting edge of straight shaft router
bit? How to test? based on say the axis of the 1/4" or 1/2" shaft
(co-axial), or compared to how flat the end is, or vice versa. Or the
surface finish itself. On a complex part, wheeeee!! These shorthand lines
are not limited to one liners, and also indicate machining operations.



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an egg sample

http://www.tec-ease.com/gdt-tips.htm



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http://global.ihs.com/doc_detail.cfm... t_doc_title=



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To my understaanding, (and I did work in a carbide manufacturing machine
shop) .001 is 1/000 of an inch. The 10 minutes is a fraction of one degree
of angle. I never heard of minutes being involved the thickness. Roughly
25/1000 inch = 1millimeter.

In article , "Michael Hearn Anna Houpt" wrote:

Roughly 25/1000 inch = 1millimeter.

Nope. 1 mm = 0.03937inches.

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

Doug Miller wrote:

In article , "Michael Hearn Anna Houpt" wrote:

Roughly 25/1000 inch = 1millimeter.

Nope. 1 mm = 0.03937inches.

--
Regards,
Doug Miller (alphageek at milmac dot com)

OR
25.4 mm = 1 inch
which may be the source of the confusion - thwe 25
in 25/1000" - 1 mm

After reading through the replies I thought of a few more things to
add.

Sure enough, in many disciplines linear measurements are expressed in
decimal format and even though you don't mention any units, 0.001 is
often referred to as 1/1000 of an inch. Or, if you are inclined to use
the metric system, this would be 1/1000 of a meter - which is very
commonly referred to as a "micron".

You did choose to include units on the second example. As others have
stated, a "minute" is a unit of angular measurement equal to 1/60 of a
degree. Ten minutes (of arc) would be 1/6 of a degree. The "+/-"
indicates that the range is a total of 1/3 of a degree (which would
likely be enough to screw up all but pointy sticks and pukey ducks).
Angles are divided into degrees, minutes, and seconds (1/60 of a
minute).

How do these two relate? Without context, the other posters are right
- it's apples and oranges. However, it's not unusual to use the linear
measurement to describe the accuracy of an angular artifact. For
example, it's very common for the accuracy of squares and angle blocks
to be specified as a total deviation from the ideal over a fixed
distance. This one specification supplies two important pieces of
information. First, it indicates how flat the gauging surface is.
Second, it indicates the maximum possible angular error (assuming that
it is lowest at one end and highest at the other).

In your example, if we assume that +/-0.001 is inches, and that it is
indicating a total error of +/-10 minutes of arc then I would suppose
that the artifact is about 3 inches long (2.908"). Such an instrument
would be inadequate for machinery setup. But, it could be used to mark
wood if you like to cut to a line.

Hope it helps.

Ed Bennett

http://www.ts-aligner.com

tommyboy wrote:
What's the difference between +- .001 and +- 10 minutes?

wrote:


Sure enough, in many disciplines linear measurements are expressed in
decimal format and even though you don't mention any units, 0.001 is
often referred to as 1/1000 of an inch. Or, if you are inclined to use
the metric system, this would be 1/1000 of a meter - which is very
commonly referred to as a "micron".

Interesting. I had always called it a millimeter g.


--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

alexy wrote:
Interesting. I had always called it a millimeter g.

OOPS! You're right. 0.001 meters is a millimeter. 0.001 mm is a
micron. Nothing like being a few orders of magnitude off...

Thanks,
Ed Bennett

http://www.ts-aligner.com

ok, GD&T is not just surface and vice versa. The control block format with
words has a nomenclature of operator, operatees, etc. Just like grammar,
its structure is immediately sensible, but is powerful using planes,
immaginary and perfect references ...

The standard suface finish symbol is a one liner and its general format is
given under

2: How to Read the Surface Finish Symbols, at
http://www.jjjtrain.com/vms/engineer...ce_finish.html.

The documents all apply to this one liner symbol, and this symbol alone



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Doug Miller wrote:

It's time to throw all their damned tea in the harbor again.

Doug, we don't always agree on things, but I'm in perfect agreement with your
sig line. Where do I get my feathered headdress?


--
It's turtles, all the way down

In article , wrote:
Doug Miller wrote:

It's time to throw all their damned tea in the harbor again.

Doug, we don't always agree on things, but I'm in perfect agreement with your
sig line. Where do I get my feathered headdress?

You'll have to make your own. Just be careful where you get the feathers. It's
apparently illegal to even possess the feathers of certain species of bird,
even if they're molted feathers that you picked up off the ground.

BTW -- I started using that sig shortly after the Supreme Court announced its
decision in Kelo vs. New London (the eminent domain ruling).

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

a meter is a meter. an inch is an inch. micro is a millionth;, theres one
million micrometers or microns in a meter. nothing to do with a .001", a
thousandth of an inch, or the imperial system. A thousandth of an ich is
for those who don't think a 64th or 128th is really a good way to divide an
inch. Its still the same inch in the first place. Just because its been
divided by ten, then that can be divided by ten, etc.does mean it has
anything to do with the metric system, micrometers or microns, which are
just that long, but historically have been divided by 10, 10, 10 etc. Each
time you divide by ten you just write down another digit, you don't need to
track down a king for a new body part.
a mil is the same thing as a 1000th of an inch .(001"). When you buy
plastic you buy 6 mil plastic, it is 6 thousandths of an inch thick. mil as
in milli, or thousandth, not million, not meteric. btw 4 mil plastic is
really thin, don't use it. If you can rip it apart its probly not to code.

A 64th of an inch is 1/64" = .015625; which is
no tenths of an inch
1 hundredths of an inch
5 thousandths of an inch
6 ten thousandths of an inch
2 hundred thousands of an inch
5 millionths of an inch

What is: most of 2 inches & 33/64ths thick subtract a half inch (well about
2/3 of a 16th less than that), shifted the majority of 7/16 to the right,
and accounting for moiture content, and alowing for the thickness of five
layers of paint on a tape measure? If I know it has to be tight to within
say 3/128"; or say at exactly the point, but projected at 90 dergrees 4
inches away at thatis point, plus or minus 1/128", bu t when that



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In article . com,
wrote:
After reading through the replies I thought of a few more things to
add.

Sure enough, in many disciplines linear measurements are expressed in
decimal format and even though you don't mention any units, 0.001 is
often referred to as 1/1000 of an inch. Or, if you are inclined to use
the metric system, this would be 1/1000 of a meter - which is very
commonly referred to as a "micron".


Uh, Ed, it is even MORE common to refer to 1/1000 of a meter as a
millimeter. A micron is 1/1000 of a millimeter, or 1/1,000,000
(millionth) of a meter.


--
No dumb questions, just dumb answers.

Larry Wasserman - Baltimore, Maryland -

Hi Larry,

Perhaps your newsreader didn't pick it up. Alexy beat you to the punch
and I already thanked him for the correction. Yep, a micron is 0.001
millimeters, not 0.001 meters. It seems to have been my day to do
things wrong by several orders of magnitude. Glad to know that good
people read these messages and don't hesitate to make sure that
mistakes are corrected.

Thanks,
Ed Bennett

http://www.ts-aligner.com

wrote:
In article . com,
wrote:
After reading through the replies I thought of a few more things to
add.

Sure enough, in many disciplines linear measurements are expressed in
decimal format and even though you don't mention any units, 0.001 is
often referred to as 1/1000 of an inch. Or, if you are inclined to use
the metric system, this would be 1/1000 of a meter - which is very
commonly referred to as a "micron".


Uh, Ed, it is even MORE common to refer to 1/1000 of a meter as a
millimeter. A micron is 1/1000 of a millimeter, or 1/1,000,000
(millionth) of a meter.


--
No dumb questions, just dumb answers.

Larry Wasserman - Baltimore, Maryland -

Hi bent,

I definitely appreciate several of the links that you have posted.
And, I appreciate the idea that fractions and decimals are just
different ways to represent the same measures. Many people see a
decimal representation like 0.015" and immediately think "that's an
absurd tolerance for woodworking" but if they see 1/64" they say
"that's appropriate for woodworking". In the angular example cited, I
think that everyone will admit that 1/3 of a degree is significant for
good joinery but when it's represented in terms of minutes of arc then
suddenly people think it's absurd. Your point is well made and the
allusion to the body parts of a king drives it all the way home.

I especially like your last point where you demonstrate the joys of
doing fractional math. There are times when working in decimals is
preferable!

However, I do believe that plastics which come in thicknesses below
0.006" (6 mil) have very practical and valid uses. ;-)

Thanks,
Ed Bennett

http://www.ts-aligner.com

bent wrote:
a meter is a meter. an inch is an inch. micro is a millionth;, theres one
million micrometers or microns in a meter. nothing to do with a .001", a
thousandth of an inch, or the imperial system. A thousandth of an ich is
for those who don't think a 64th or 128th is really a good way to divide an
inch. Its still the same inch in the first place. Just because its been
divided by ten, then that can be divided by ten, etc.does mean it has
anything to do with the metric system, micrometers or microns, which are
just that long, but historically have been divided by 10, 10, 10 etc. Each
time you divide by ten you just write down another digit, you don't need to
track down a king for a new body part.
a mil is the same thing as a 1000th of an inch .(001"). When you buy
plastic you buy 6 mil plastic, it is 6 thousandths of an inch thick. mil as
in milli, or thousandth, not million, not meteric. btw 4 mil plastic is
really thin, don't use it. If you can rip it apart its probly not to code.

A 64th of an inch is 1/64" = .015625; which is
no tenths of an inch
1 hundredths of an inch
5 thousandths of an inch
6 ten thousandths of an inch
2 hundred thousands of an inch
5 millionths of an inch

What is: most of 2 inches & 33/64ths thick subtract a half inch (well about
2/3 of a 16th less than that), shifted the majority of 7/16 to the right,
and accounting for moiture content, and alowing for the thickness of five
layers of paint on a tape measure? If I know it has to be tight to within
say 3/128"; or say at exactly the point, but projected at 90 dergrees 4
inches away at thatis point, plus or minus 1/128", bu t when that



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