wrote:
From your words/diagram, it looks like delta1, delta2, and L are all

the same.
Not at all. The red d2 is above the red line. d denotes distance.

The passage "take a reading at the bottom of the square (d2 in Figure 1)" should have clued you in that d was a distance. We are, after all, discussing a dial indicator method. Dial indicators measure distances.


I guess that we never had a "meeting of the minds" as to what your
procedure was. More descriptive writing would probably help.

Sorry for any mix-up I may have contributed!

Bill

On Thursday, January 3, 2013 9:32:58 PM UTC-5, Doug Miller wrote:
wrote in news:bc9297af-00ce-44cd-8f63-cfff2cea2c50

@googlegroups.com:





I like to have at least one master square that I know is balls to wall accurate. I had no way

of checking before and I do now. The Draw-A-Line and flip method will never tell you how

far out of wack your square is



Pfui. Of course it will. The more the lines diverge, the more out of whack it is.

"More out of wack" is not a quantity. I can only be used in relative terms. 'This' is more out of wack than 'this'.




- only that it might be out of wack. There is no way to quantitate the angle error unless you

can measure the distance betwene the lines/knife marks with a caliper (good luck).



That'll work. Feeler gauges will probably work better.

Huh? Measure the distance between two lines with a feeler gauges?



How much of a gap in between the marks is considered unacceptable? You can't easily

answer that question so why bother checking in the first place?



Of course you can easily answer that question. Decide what percentage error is

acceptable in your project, and you can easily calculate the permissible gap between the

marks. Suppose you want accuracy to one part in 1000 (99.9%).

So you decide before hand the accuracy you want to achieve and then choose the appropriate square? Do you have different squares for different jobs? Are they labeled as such?

The gap between the

pencil lines at a distance of 8" -- double the error in the square, remember -- must be no

more than 8 * 2/1000 = 0.016", which is easily measurable with feeler gauges, a dial caliper,

or a mike.


A distance of 0.016" equates to an angle error of 0.5 degrees for your 8" square. Would you calibrate anything with that "Square"? I wouldn't.

What is your limit of detection for measuring gaps between lines? I hope it's less than 0.016", but I can understand if it's not.

wrote:
On Thursday, January 3, 2013 9:32:58 PM UTC-5, Doug Miller wrote:
That'll work. Feeler gauges will probably work better.
Huh? Measure the distance between two lines with a feeler gauges?

You mean between two points--or two parallel lines. I agree that feeler
guages seem suitable.

Bill

wrote in news:214a7bab-b962-477d-8340-
:

Scenario: You make it out to the woodshop after a hard night of drinking. As the
acetaldehyde takes it's effect on you, you drop your Starrett square on the concrete floor.

Doesn't happen in my shop. That's a hard and fast safety rule he if I drink, I stay out of the
shop until after a full night's sleep.

That doesn't mean I can't or won't ever drop the square, of course -- just means that if I do, it
will be the result of my own innate clumsiness, not of inebriation.

What do you do? Continue to use it and hope for the best or check to see if it's still of
'Starrett Quality'? How do you check?

Your imagination is lacking, Brian g. I can think of at least half a dozen things I could
check it against:
-- angle between the jointer fence and bed (previously set using the same Starrett square)
-- angle between the fence of the Incra 3000 miter gauge, and the miter bar (ditto)
-- angle between the Incra 3000 and the table saw blade (ditto)
-- one of my Jevons 3D squares http://www.jevonstoolco.com/ -- I have no connection
with the company, except as a *totally* satisfied customer -- these are great products, and
as close to dead-on-perfect as a woodworking tool needs to be (within 0.002" in 6",
according to the manufacturer)
-- my crosscut sled
-- any corner of at least seven pieces of furniture in my home that I've made using some or
all of the above

On Thursday, January 3, 2013 9:42:29 PM UTC-5, Bill wrote:
wrote:

Yes they are. I am 'referring' to them in the article. It's done routinely in the literature.

References usally means bibliographical references (to related works).

Yes, usually. It is however, not incorrect how I used the term.









"Notes" may be more appropriate (I'm not looking for an argument).

I like references. It's what I'm used to.







When you submit your work for publication, the publisher will advise you

in no uncertain terms how it it should appear.

I've read more than my fair share of peer reviewed scientific publications. And as a scientist, I've written a few peer reviewed as well. I have never heard of a reviewer who had a problem with using 'References' in the fashion that I did.



While your idea may be just fine, having reviewed a few books and papers

before, it is my humble opinion your your paper needs work.

You can't please everyone. Isn't that what they say?


I would look forward to seeing your ideas presented again. As has been

suggested, this isn't rocket science, but the application of using

the magnetic cubes to check for accuracy in squares is an interesting

application. Why settle for good-enough.

Magnetic cubes?




Bill

On Thursday, January 3, 2013 9:54:35 PM UTC-5, Doug Miller wrote:
wrote in news:214a7bab-b962-477d-8340-

:



Scenario: You make it out to the woodshop after a hard night of drinking. As the

acetaldehyde takes it's effect on you, you drop your Starrett square on the concrete floor.



Doesn't happen in my shop. That's a hard and fast safety rule he if I drink, I stay out of the

shop until after a full night's sleep.



That doesn't mean I can't or won't ever drop the square, of course -- just means that if I do, it

will be the result of my own innate clumsiness, not of inebriation.



What do you do? Continue to use it and hope for the best or check to see if it's still of

'Starrett Quality'? How do you check?



Your imagination is lacking, Brian g. I can think of at least half a dozen things I could

check it against:

-- angle between the jointer fence and bed (previously set using the same Starrett square)

How can you be sure it's still square to the level of accuracy required?



-- angle between the fence of the Incra 3000 miter gauge, and the miter bar (ditto)

ibid


-- angle between the Incra 3000 and the table saw blade (ditto)

ibid


-- one of my Jevons 3D squares http://www.jevonstoolco.com/ -- I have no connection

with the company, except as a *totally* satisfied customer -- these are great products, and

as close to dead-on-perfect as a woodworking tool needs to be (within 0.002" in 6",

according to the manufacturer)

-- my crosscut sled

ibid


-- any corner of at least seven pieces of furniture in my home that I've made using some or

I hope you're joking.


all of the above

wrote in news:5443d0e1-47e2-4bf4-9dc6-237d07bf6357
@googlegroups.com:

There is no need to "try again" and I appreciate your veiled arrogance.

Where are you having trouble with the math?

Ummm.... Brian, you don't know Bill personally. I do.

He's not the sort of guy to toot his own horn, so without his consent, I'm not going to say why I'm
so sure of it, but please trust me on this: the man *knows* math.

On Thursday, January 3, 2013 10:01:36 PM UTC-5, Doug Miller wrote:
wrote in news:5443d0e1-47e2-4bf4-9dc6-237d07bf6357

@googlegroups.com:



There is no need to "try again" and I appreciate your veiled arrogance.



Where are you having trouble with the math?



Ummm.... Brian, you don't know Bill personally. I do.



He's not the sort of guy to toot his own horn, so without his consent, I'm not going to say why I'm

so sure of it, but please trust me on this: the man *knows* math.

Good. The math is sound. Let's see something from Bill to the contrary.

I've checked it and rechecked it.

On Thu, 3 Jan 2013 13:58:44 -0800 (PST),
wrote:

Let me know what you guys think.

I've been working on a new method (new?) for checking the squareness of a square using a dial indicator. The method works in theory. I've tried it and it seems to work in practice. A caveat is that the square needs a thick edge to support a stylus.

I am going to work on a video demonstrating the process.

http://www.garagewoodworks.com/square_a_square.php

Thoughts?

Are you off your meds again?

On 1/3/2013 6:30 PM, wrote:
On Thursday, January 3, 2013 6:24:52 PM UTC-5, Dave Balderstone wrote:
In article ,

wrote:



Let me know what you guys think.



I've been working on a new method (new?) for checking the squareness of a

square using a dial indicator. The method works in theory. I've tried it

and it seems to work in practice. A caveat is that the square needs a thick

edge to support a stylus.



I am going to work on a video demonstrating the process.



http://www.garagewoodworks.com/square_a_square.php



Thoughts?



Seems totally unnecessary. A pencil and a straight edge (a la sheet

good cutoff) is all you need to check if it's actually square. And it's

fast to set up.

read the article.


A minor caveat to this method is that it can be difficult to discern small gaps between the two pencil lines (especially with a thick pencil lead). The most you might be able to detect is a 0.010" difference which equates to a minimum detection of 0.036 degrees with an 8" square.
Another caveat is that the edge you place your square against must be perfectly flat, otherwise you will not get an accurate calculation of your square's angle error.


The dial indicator method is 10X more accurate.




--

Outside of a dog, a book is man's best friend. Inside a dog, it's too dark to

read. - Groucho Marx

Then use a marking knife.

On Thursday, January 3, 2013 10:05:16 PM UTC-5, Gordon Shumway wrote:
On Thu, 3 Jan 2013 13:58:44 -0800 (PST),

wrote:



Let me know what you guys think.



I've been working on a new method (new?) for checking the squareness of a square using a dial indicator. The method works in theory. I've tried it and it seems to work in practice. A caveat is that the square needs a thick edge to support a stylus.



I am going to work on a video demonstrating the process.



http://www.garagewoodworks.com/square_a_square.php



Thoughts?



Are you off your meds again?

Too complex for you I know. I'll dumb it down for you next time.

On Thursday, January 3, 2013 10:06:49 PM UTC-5, tiredofspam wrote:
On 1/3/2013 6:30 PM, wrote:

On Thursday, January 3, 2013 6:24:52 PM UTC-5, Dave Balderstone wrote:

In article ,



wrote:







Let me know what you guys think.







I've been working on a new method (new?) for checking the squareness of a



square using a dial indicator. The method works in theory. I've tried it



and it seems to work in practice. A caveat is that the square needs a thick



edge to support a stylus.







I am going to work on a video demonstrating the process.







http://www.garagewoodworks.com/square_a_square.php







Thoughts?







Seems totally unnecessary. A pencil and a straight edge (a la sheet



good cutoff) is all you need to check if it's actually square. And it's



fast to set up.



read the article.





A minor caveat to this method is that it can be difficult to discern small gaps between the two pencil lines (especially with a thick pencil lead). The most you might be able to detect is a 0.010" difference which equates to a minimum detection of 0.036 degrees with an 8" square.

Another caveat is that the edge you place your square against must be perfectly flat, otherwise you will not get an accurate calculation of your square's angle error.





The dial indicator method is 10X more accurate.









--



Outside of a dog, a book is man's best friend. Inside a dog, it's too dark to



read. - Groucho Marx



Then use a marking knife.

You're still left with not being able to quantitate the error. Are you following along?

wrote:

Let me know what you guys think.
-----------------------------------------------------------
A slow night in the Carolinas.

Lew

On 1/3/2013 6:45 PM, wrote:
....

If it passes the pencil test, it's plenty close enough for woodworking;

What is a "pass" on the pencil test?
....

I'm sure you're clever enough to figure it out...

--

On Thursday, January 3, 2013 10:19:46 PM UTC-5, Lew Hodgett wrote:
wrote:



Let me know what you guys think.

-----------------------------------------------------------

A slow night in the Carolinas.

Then go out and get a drink Lew! Get off yer butt!




Lew

wrote in
:

On Thursday, January 3, 2013 9:32:58 PM UTC-5, Doug Miller
wrote:
wrote in
news:bc9297af-00ce-44cd-8f63-cfff2cea2c50

@googlegroups.com:





I like to have at least one master square that I know is
balls to wall accurate. I had no way

of checking before and I do now. The Draw-A-Line and flip
method will never tell you how

far out of wack your square is



Pfui. Of course it will. The more the lines diverge, the more
out of whack it is.

"More out of wack" is not a quantity. I can only be used in
relative terms. 'This' is more out of wack than 'this'.

Yes, and I was using it in relative terms. Where's the problem?

- only that it might be out of wack. There is no way to
quantitate the angle error unless you

can measure the distance betwene the lines/knife marks with a
caliper (good luck).



That'll work. Feeler gauges will probably work better.

Huh? Measure the distance between two lines with a feeler
gauges?

Sure, why not? You can easily see if the gauge overlaps the lines
or fits between them. BTW, the width of the pencil lines isn't
really relevant -- use a marking knife instead of a pencil.



How much of a gap in between the marks is considered
unacceptable? You can't easily

answer that question so why bother checking in the first place?



Of course you can easily answer that question. Decide what
percentage error is

acceptable in your project, and you can easily calculate the
permissible gap between the

marks. Suppose you want accuracy to one part in 1000 (99.9%).

So you decide before hand the accuracy you want to achieve and
then choose the appropriate square?

Of course.

Do you have different squares for different jobs? Are they
labeled as such?

I have a Starrett square that never leaves the wood shop. I also
have a Craftsman combination square, and a Stanley framing square,
that I use for carpentry projects. It never crossed my mind to use
the Starrett when I built a shed in the back yard a few years ago,
or when my son and I built a deck last summer -- that degree of
precision simply isn't needed, and there's no point in risking an
expensive precision tool on a construction site.

The gap between the pencil lines at a distance of 8" -- double
the error in the square, remember -- must be no more than 8 *
2/1000 = 0.016", which is easily measurable with feeler gauges,
a dial caliper, or a mike.


A distance of 0.016" equates to an angle error of 0.5 degrees
for your 8" square.

No it does not.

First of all, 0.016" is double the error, so the actual error is
0.008" over 8" or 0.001. The inverse tangent of 0.001 is 0.0573
degrees (rounded to 3 significant digits). If you want to be
really picky, the 8" distance is actually the hypotenuse of the
triangle, so we should use inverse sine instead, but the result is
the same to at least the seventh decimal place.

Would you calibrate anything with that "Square"? I wouldn't.

I wouldn't either -- *if* your number was right. It's not, though,
and I'm not sure why you seem to have a problem with using a
square that's accurate to one part in a thousand for woodworking.

What is your limit of detection for measuring gaps between
lines? I hope it's less than 0.016", but I can understand if
it's not.

I can estimate much finer gaps than that by eye. The thinnest
feeler gauge I own is 0.001"; anything less than that is too
fragile for wood shop use, and is pointless anyway. In practice, a
0.002" gauge is quite sufficient for woodworking.

wrote in message
...

On Thursday, January 3, 2013 6:24:52 PM UTC-5, Dave Balderstone wrote:
In article ,

wrote:



Let me know what you guys think.



I've been working on a new method (new?) for checking the squareness of
a

square using a dial indicator. The method works in theory. I've tried
it

and it seems to work in practice. A caveat is that the square needs a
thick

edge to support a stylus.



I am going to work on a video demonstrating the process.



http://www.garagewoodworks.com/square_a_square.php



Thoughts?



Seems totally unnecessary. A pencil and a straight edge (a la sheet

good cutoff) is all you need to check if it's actually square. And it's

fast to set up.

read the article.


A minor caveat to this method is that it can be difficult to discern
small gaps between the two pencil lines (especially with a thick pencil
lead). The most you might be able to detect is a 0.010" difference which
equates to a minimum detection of 0.036 degrees with an 8" square.
Another caveat is that the edge you place your square against must be
perfectly flat, otherwise you will not get an accurate calculation of your
square's angle error.
================================================== ================================================== ================================================== ========
Use a knife to mark and do it on a flat smooth surface. MDF or. better yet,
a piece of metal covered in dykem blue. Make your line as light as possible.
Use magnifier. A discrepancy of .001 is readily visible.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
The dial indicator method is 10X more accurate
================================================== =========================================
Got a metal lathe? If you do, it can be used to make a master square that is
more accurate than anything you can buy for less than several hundred
dollars. Not needed though. Use the flip and mark
method.

I wrote:

A slow night in the Carolinas.
---------------------------------------------

wrote:


Then go out and get a drink Lew! Get off yer butt!
------------------------------------------------------
You must be kidding, it's 50F and dropping tonight.

Time to throw another log on the fire and enjoy
a toddy.

Lew

On Thursday, January 3, 2013 10:28:59 PM UTC-5, Doug Miller wrote:
wrote in

:



On Thursday, January 3, 2013 9:32:58 PM UTC-5, Doug Miller

wrote:

wrote in

news:bc9297af-00ce-44cd-8f63-cfff2cea2c50



@googlegroups.com:











I like to have at least one master square that I know is

balls to wall accurate. I had no way



of checking before and I do now. The Draw-A-Line and flip

method will never tell you how



far out of wack your square is







Pfui. Of course it will. The more the lines diverge, the more

out of whack it is.



"More out of wack" is not a quantity. I can only be used in

relative terms. 'This' is more out of wack than 'this'.



Yes, and I was using it in relative terms. Where's the problem?



- only that it might be out of wack. There is no way to

quantitate the angle error unless you



can measure the distance betwene the lines/knife marks with a

caliper (good luck).







That'll work. Feeler gauges will probably work better.



Huh? Measure the distance between two lines with a feeler

gauges?



Sure, why not? You can easily see if the gauge overlaps the lines

or fits between them. BTW, the width of the pencil lines isn't

really relevant -- use a marking knife instead of a pencil.







How much of a gap in between the marks is considered

unacceptable? You can't easily



answer that question so why bother checking in the first place?







Of course you can easily answer that question. Decide what

percentage error is



acceptable in your project, and you can easily calculate the

permissible gap between the



marks. Suppose you want accuracy to one part in 1000 (99.9%).



So you decide before hand the accuracy you want to achieve and

then choose the appropriate square?



Of course.



Do you have different squares for different jobs? Are they

labeled as such?



I have a Starrett square that never leaves the wood shop. I also

have a Craftsman combination square, and a Stanley framing square,

that I use for carpentry projects. It never crossed my mind to use

the Starrett when I built a shed in the back yard a few years ago,

or when my son and I built a deck last summer -- that degree of

precision simply isn't needed, and there's no point in risking an

expensive precision tool on a construction site.



The gap between the pencil lines at a distance of 8" -- double

the error in the square, remember -- must be no more than 8 *

2/1000 = 0.016", which is easily measurable with feeler gauges,

a dial caliper, or a mike.





A distance of 0.016" equates to an angle error of 0.5 degrees

for your 8" square.



No it does not.



First of all, 0.016" is double the error, so the actual error is

0.008" over 8" or 0.001. The inverse tangent of 0.001 is 0.0573

That's not how the math is done.

If your gap between the two lines (drawn from the same point) is 0.016" then half the distance is 0.008" which is your "Opposite Side". Now I understand the confusion here.

See:
http://www.garagewoodworks.com/angle...e=0.008&angle=

Your Opposite side is 0.008". The Adjacent side is 8".


degrees (rounded to 3 significant digits). If you want to be

really picky, the 8" distance is actually the hypotenuse of the

triangle, so we should use inverse sine instead, but the result is

the same to at least the seventh decimal place.



Would you calibrate anything with that "Square"? I wouldn't.



I wouldn't either -- *if* your number was right. It's not, though,

and I'm not sure why you seem to have a problem with using a

square that's accurate to one part in a thousand for woodworking.



What is your limit of detection for measuring gaps between

lines? I hope it's less than 0.016", but I can understand if

it's not.



I can estimate much finer gaps than that by eye.

And I once caught a fish ------This Big------.

The thinnest

feeler gauge I own is 0.001"; anything less than that is too

fragile for wood shop use, and is pointless anyway. In practice, a

0.002" gauge is quite sufficient for woodworking.

wrote in
:

On Thursday, January 3, 2013 9:54:35 PM UTC-5, Doug Miller
wrote:
wrote in
news:214a7bab-b962-477d-8340-

:



Scenario: You make it out to the woodshop after a hard night
of drinking. As the acetaldehyde takes it's effect on you,
you drop your Starrett square on the concrete floor.



Doesn't happen in my shop. That's a hard and fast safety rule
he if I drink, I stay out of the shop until after a full
night's sleep.

That doesn't mean I can't or won't ever drop the square, of
course -- just means that if I do, it will be the result of my
own innate clumsiness, not of inebriation.

What do you do? Continue to use it and hope for the best or
check to see if it's still of
'Starrett Quality'? How do you check?

Your imagination is lacking, Brian g. I can think of at least
half a dozen things I could check it against:

-- angle between the jointer fence and bed (previously set
using the same Starrett square)

How can you be sure it's still square to the level of accuracy
required?

I check it periodically, using both the Starrett and the Jevons
squares. Don't you?

-- angle between the fence of the Incra 3000 miter gauge, and
the miter bar (ditto)

ibid

same answer

-- angle between the Incra 3000 and the table saw blade (ditto)

ibid

same answer

-- one of my Jevons 3D squares http://www.jevonstoolco.com/
-- I have no connection with the company, except as a
*totally* satisfied customer -- these are great products, and
as close to dead-on-perfect as a woodworking tool needs to be
(within 0.002" in 6", according to the manufacturer)

-- my crosscut sled

ibid

same answer


-- any corner of at least seven pieces of furniture in my home
that I've made using some or all of the above

I hope you're joking.

Why would you think that?

Just for giggles and grins, I just checked a corner of an end
table that I made about 12 years ago -- put the head of the
Starrett square against a corner of the tabletop, and tried to
slip a 0.002" feeler gauge between the blade and the tabletop. It
won't fit, anywhere within 7 1/2 inches of the corner.

I'm satisfied with 99.97%.

wrote in news:ee116537-b047-4754-88e2-dfc87af63570
@googlegroups.com:

On Thursday, January 3, 2013 10:06:49 PM UTC-5, tiredofspam wrote:
Then use a marking knife.

You're still left with not being able to quantitate the error. Are you following along?

_Of course_ you can "quantitate" [sic] the error. What makes you think it can't be measured?

On Thursday, January 3, 2013 10:28:59 PM UTC-5, Doug Miller wrote:
wrote in

:



On Thursday, January 3, 2013 9:32:58 PM UTC-5, Doug Miller

wrote:

wrote in

news:bc9297af-00ce-44cd-8f63-cfff2cea2c50



@googlegroups.com:











I like to have at least one master square that I know is

balls to wall accurate. I had no way



of checking before and I do now. The Draw-A-Line and flip

method will never tell you how



far out of wack your square is







Pfui. Of course it will. The more the lines diverge, the more

out of whack it is.



"More out of wack" is not a quantity. I can only be used in

relative terms. 'This' is more out of wack than 'this'.



Yes, and I was using it in relative terms. Where's the problem?



- only that it might be out of wack. There is no way to

quantitate the angle error unless you



can measure the distance betwene the lines/knife marks with a

caliper (good luck).







That'll work. Feeler gauges will probably work better.



Huh? Measure the distance between two lines with a feeler

gauges?



Sure, why not? You can easily see if the gauge overlaps the lines

or fits between them. BTW, the width of the pencil lines isn't

really relevant -- use a marking knife instead of a pencil.







How much of a gap in between the marks is considered

unacceptable? You can't easily



answer that question so why bother checking in the first place?







Of course you can easily answer that question. Decide what

percentage error is



acceptable in your project, and you can easily calculate the

permissible gap between the



marks. Suppose you want accuracy to one part in 1000 (99.9%).



So you decide before hand the accuracy you want to achieve and

then choose the appropriate square?



Of course.



Do you have different squares for different jobs? Are they

labeled as such?



I have a Starrett square that never leaves the wood shop. I also

have a Craftsman combination square, and a Stanley framing square,

that I use for carpentry projects. It never crossed my mind to use

the Starrett when I built a shed in the back yard a few years ago,

or when my son and I built a deck last summer -- that degree of

precision simply isn't needed, and there's no point in risking an

expensive precision tool on a construction site.



The gap between the pencil lines at a distance of 8" -- double

the error in the square, remember -- must be no more than 8 *

2/1000 = 0.016", which is easily measurable with feeler gauges,

a dial caliper, or a mike.





A distance of 0.016" equates to an angle error of 0.5 degrees

for your 8" square.



No it does not.



First of all, 0.016" is double the error, so the actual error is

0.008" over 8" or 0.001. The inverse tangent of 0.001 is 0.0573

degrees (rounded to 3 significant digits). If you want to be

really picky, the 8" distance is actually the hypotenuse of the

triangle, so we should use inverse sine instead, but the result is

the same to at least the seventh decimal place.



Would you calibrate anything with that "Square"? I wouldn't.



I wouldn't either -- *if* your number was right. It's not, though,

and I'm not sure why you seem to have a problem with using a

square that's accurate to one part in a thousand for woodworking.



What is your limit of detection for measuring gaps between

lines? I hope it's less than 0.016", but I can understand if

it's not.



I can estimate much finer gaps than that by eye. The thinnest

feeler gauge I own is 0.001"; anything less than that is too

fragile for wood shop use, and is pointless anyway. In practice, a

0.002" gauge is quite sufficient for woodworking.

Crap, you're right. It is 0.057. I misread a decimal place. Apologies.

On Thu, 03 Jan 2013 19:09:31 -0600, -MIKE-
wrote:





Again, we're back to my original point. We're talking woodworking. How
exact does a 2' square need to be?

If I can't see it in the finished product, it is close enough. If a
bookcase does not rack and fall down, it is square enough.

On Thursday, January 3, 2013 10:45:21 PM UTC-5, Doug Miller wrote:
wrote in news:ee116537-b047-4754-88e2-dfc87af63570

@googlegroups.com:



On Thursday, January 3, 2013 10:06:49 PM UTC-5, tiredofspam wrote:

Then use a marking knife.



You're still left with not being able to quantitate the error. Are you following along?



_Of course_ you can "quantitate" [sic] the error. What makes you think it can't be measured?

Measure thousands of an inch between two lines. Sure it can be measured. Accurately? No.

wrote in news:bccdd6ea-eb29-401f-8b92-b76c1cb38818
@googlegroups.com:

That's not how the math is done.

LMAO

If your gap between the two lines (drawn from the same point) is 0.016" then half the
distance is 0.008" which is your "Opposite Side". Now I understand the confusion here.

See:
http://www.garagewoodworks.com/angle...e=0.008&angle=

Your Opposite side is 0.008". The Adjacent side is 8".

And tangent = opposite / adjacent = 0.008 / 8 = 0.001.

(As I noted previously, the 8" is actually the hypotenuse, not the adjacent side, but for
angles this small, it doesn't matter.)

Anyway... arctan (0.001) IS NOT 0.5 degrees. You're off by an order of magnitude.
[...]
What is your limit of detection for measuring gaps between
lines? I hope it's less than 0.016", but I can understand if
it's not.

I can estimate much finer gaps than that by eye.

And I once caught a fish ------This Big------.

If you *can't* tell the difference between a gap of sixteen thou and a gap of six thou without
using precision equipment, then you need to visit an optometrist. Seriously.

On Thursday, January 3, 2013 10:43:22 PM UTC-5, Doug Miller wrote:
wrote in

:



On Thursday, January 3, 2013 9:54:35 PM UTC-5, Doug Miller

wrote:

wrote in

news:214a7bab-b962-477d-8340-



:







Scenario: You make it out to the woodshop after a hard night

of drinking. As the acetaldehyde takes it's effect on you,

you drop your Starrett square on the concrete floor.







Doesn't happen in my shop. That's a hard and fast safety rule

he if I drink, I stay out of the shop until after a full

night's sleep.



That doesn't mean I can't or won't ever drop the square, of

course -- just means that if I do, it will be the result of my

own innate clumsiness, not of inebriation.



What do you do? Continue to use it and hope for the best or

check to see if it's still of

'Starrett Quality'? How do you check?



Your imagination is lacking, Brian g. I can think of at least

half a dozen things I could check it against:



-- angle between the jointer fence and bed (previously set

using the same Starrett square)



How can you be sure it's still square to the level of accuracy

required?



I check it periodically, using both the Starrett and the Jevons

squares. Don't you?

I periodically check my jointer fence with a dial indicator (Powermatic) and it's always off by +/- 0.003". I shim the pos stop w/ paper when needed.

I wouldn't square anything against it as a reference.




-- angle between the fence of the Incra 3000 miter gauge, and

the miter bar (ditto)



ibid



same answer

Same goes for my Osborne EB3 that hangs on a wall. It needs periodic adjusting.




-- angle between the Incra 3000 and the table saw blade (ditto)



ibid



same answer




-- one of my Jevons 3D squares http://www.jevonstoolco.com/

-- I have no connection with the company, except as a

*totally* satisfied customer -- these are great products, and

as close to dead-on-perfect as a woodworking tool needs to be

(within 0.002" in 6", according to the manufacturer)



-- my crosscut sled



ibid



same answer





-- any corner of at least seven pieces of furniture in my home

that I've made using some or all of the above



I hope you're joking.



Why would you think that?



Just for giggles and grins, I just checked a corner of an end

table that I made about 12 years ago -- put the head of the

Starrett square against a corner of the tabletop, and tried to

slip a 0.002" feeler gauge between the blade and the tabletop. It

won't fit, anywhere within 7 1/2 inches of the corner.



I'm satisfied with 99.97%.

wrote in
:

On Thursday, January 3, 2013 10:45:21 PM UTC-5, Doug Miller
wrote:
wrote in
news:ee116537-b047-4754-88e2-dfc87af63570

@googlegroups.com:



On Thursday, January 3, 2013 10:06:49 PM UTC-5, tiredofspam
wrote:

Then use a marking knife.



You're still left with not being able to quantitate the
error. Are you following along?



_Of course_ you can "quantitate" [sic] the error. What makes
you think it can't be measured?

Measure thousands of an inch between two lines. Sure it can be
measured. Accurately? No.

What makes you think that? Do you own a set of feeler gauges?

wrote in news:c844cf2e-258c-4d91-bdd5-
:


Crap, you're right. It is 0.057. I misread a decimal place. Apologies.

Accepted. Thank you.

On Thursday, January 3, 2013 10:42:05 PM UTC-5, Lew Hodgett wrote:
I wrote:



A slow night in the Carolinas.

---------------------------------------------



wrote:





Then go out and get a drink Lew! Get off yer butt!

------------------------------------------------------

You must be kidding, it's 50F and dropping tonight.



Time to throw another log on the fire and enjoy

a toddy.

Man I wish we had a log fireplace. The fake gas log variety just doesn't cut it.




Lew

wrote in news:6bb06987-59c5-4cc0-a902-
:

I periodically check my jointer fence with a dial indicator (Powermatic) and it's always off by
+/- 0.003". I shim the pos stop w/ paper when needed.

I wouldn't square anything against it as a reference.

It is at least close enough to tell you if you've damaged a precision square by dropping it on
the floor...

On Thursday, January 3, 2013 10:53:50 PM UTC-5, Doug Miller wrote:
wrote in news:bccdd6ea-eb29-401f-8b92-b76c1cb38818

@googlegroups.com:



That's not how the math is done.



LMAO

See my other post. I misplaced a decimal. Happens sometimes.




If your gap between the two lines (drawn from the same point) is 0.016" then half the

distance is 0.008" which is your "Opposite Side". Now I understand the confusion here.



See:

http://www.garagewoodworks.com/angle...e=0.008&angle=



Your Opposite side is 0.008". The Adjacent side is 8".



And tangent = opposite / adjacent = 0.008 / 8 = 0.001.



(As I noted previously, the 8" is actually the hypotenuse, not the adjacent side, but for

angles this small, it doesn't matter.)



Anyway... arctan (0.001) IS NOT 0.5 degrees. You're off by an order of magnitude.

[...]

What is your limit of detection for measuring gaps between

lines? I hope it's less than 0.016", but I can understand if

it's not.



I can estimate much finer gaps than that by eye.



And I once caught a fish ------This Big------.



If you *can't* tell the difference between a gap of sixteen thou and a gap of six thou without


I can discern a difference. But i wouldn't be able to quantitate the two gaps to the level of accuracy required. And neither can you.


using precision equipment, then you need to visit an optometrist. Seriously.

wrote in message
...

On Thursday, January 3, 2013 6:57:37 PM UTC-5, -MIKE- wrote:
On 1/3/13 5:30 PM, wrote:

A minor caveat to this method is that it can be difficult to discern

small gaps between the two pencil lines (especially with a thick

pencil lead).



Use a knife.





The most you might be able to detect is a 0.010"

difference which equates to a minimum detection of 0.036 degrees with

an 8" square. Another caveat is that the edge you place your square

against must be perfectly flat, otherwise you will not get an

accurate calculation of your square's angle error.





The dial indicator method is 10X more accurate.





Great, if we need to send a rocket into space, but not necessary for

woodworking. :-)

I like to have at least one master square that I know is balls to wall
accurate. I had no way of checking before and I do now. The Draw-A-Line
and flip method will never tell you how far out of wack your square is -
only that it might be out of wack. There is no way to quantitate the angle
error unless you can measure the distance betwene the lines/knife marks with
a caliper (good luck). How much of a gap in between the marks is considered
unacceptable? You can't easily answer that question so why bother checking
in the first place?
================================================== ================================================== ================================================
There are a number of ways to measure that gap. With the tools that I know
you have, a drill press, a dial indicator, a piece of chewing gum (pre
chewed) and a pin will allow you to measure to .002 or less.





--



-MIKE-



"Playing is not something I do at night, it's my function in life"

--Elvin Jones (1927-2004)

--

http://mikedrums.com



---remove "DOT" ^^^^ to reply

On Thursday, January 3, 2013 10:55:23 PM UTC-5, Doug Miller wrote:
wrote in

:



On Thursday, January 3, 2013 10:45:21 PM UTC-5, Doug Miller

wrote:

wrote in

news:ee116537-b047-4754-88e2-dfc87af63570



@googlegroups.com:







On Thursday, January 3, 2013 10:06:49 PM UTC-5, tiredofspam

wrote:



Then use a marking knife.







You're still left with not being able to quantitate the

error. Are you following along?







_Of course_ you can "quantitate" [sic] the error. What makes

you think it can't be measured?



Measure thousands of an inch between two lines. Sure it can be

measured. Accurately? No.



What makes you think that? Do you own a set of feeler gauges?

I have never needed feeler gauges. They work on a very basic principle and I feel confident making that claim.

On 1/3/13 7:18 PM, wrote:
Again, we're back to my original point. We're talking woodworking. How

exact does a 2' square need to be? In my mind, within the width of the

edge of an exact blade over 2' is plenty close.

When is it not close? Two blade widths? Three? And why?


Isn't that up to you? If you're doing woodworking, how far in the plane
of your square do you need? Like I said, are you using a 2' square to
set up a rips guide to rip plywood? If so, you probably need a new
technique. But even if you are, I bet I could set up a square using the
mark and flip method and have it dead nuts on.



Using the mark and flip

method is plenty good enough. If a person doesn't have a factory edged,

2'x4' piece of plywood or mdf at his disposal somewhere, he probably

shouldn't be woodworking. An aluminum straight edge clamped to a work

bench does fine in that regard, as well. Something a woodworking

shouldn't be without, either.





Do you have

an adjustment method that you dial in an amount and it corrects that much?



No. But I'll know what contributed to my joints not being square.





I can use the mark and flip method to know if my square contributed to

my out of square joints.

Again. By what means does the flip method tell you to drop the square in the trash? And why?


Again, isn't that up to you. I'm ready to replace my steel square with a
precision t-square. I check the the thing before every project for which
I'll be using it... like these bookcases. Maybe two years ago, I had to
adjust it using a nail punch. I suppose I could've thrown it away, but
most squares on the hardware store shelves under $50 are hit and miss...
so I adjusted mine.

This really seems like a lot of arguing for you to try to validate your
technique for adjusting a satellite telescope for use in woodworking. :-p


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com

---remove "DOT" ^^^^ to reply

Ed Pawlowski wrote in news:62kce89sa9i1ad6g19q28uajp7vharjmau@
4ax.com:

On Thu, 03 Jan 2013 19:09:31 -0600, -MIKE-
wrote:

Again, we're back to my original point. We're talking woodworking. How
exact does a 2' square need to be?

If I can't see it in the finished product, it is close enough. If a
bookcase does not rack and fall down, it is square enough.

g

Some years ago, I formulated these rules of thumb. If a piece of any significant size is out of
square, level, or plumb by...

1 part in 100 -- *immediately obvious* to a casual observer (don't believe me? get a level
and check, the next time it's immediately obvious that a picture on your wall doesn't hang
straight)

1 part in 200 -- apparent to anyone who is looking for flaws

1 part in 400 -- won't be seen, but can be readily found with common carpentry tools (level,
tape measure, etc)

1 part in 800 -- can't be found without precision measuring tools

The significance of these rules is that the accuracy of your work won't be any better than the
accuracy of the tools you produce it with (e.g. you can't get 1 part in 800 results with a
"square" that measures 89.7 degrees).

wrote:

Man I wish we had a log fireplace. The fake gas log variety just
doesn't cut it.
------------------------------------------------------------------
You can forget a log fireplace in SoCal.

The South Coast Air Quality District outlawed open log fire burning
fire places years ago as an air pollution source problem.

Lew

wrote in news:cfc901eb-e547-4589-a3e9-
:

I have never needed feeler gauges. They work on a very basic principle and I feel confident
making that claim.


I hope you'll pardon this small correction: you have never *perceived* the need for feeler
gauges.

IMHO you should reevaluate that perception.

wrote in news:2c3d3ffb-c20b-43fd-bcae-d1b6b820fe51
@googlegroups.com:

If you *can't* tell the difference between a gap of sixteen thou and a gap of six thou without


I can discern a difference. But i wouldn't be able to quantitate the two gaps to the level of
accuracy required. And neither can you.

Don't tell me what I can and can't do.

You don't own feeler gauges, so you don't know how small a gap is visible, or how accurately
it can be estimated with a little practice.

"Doug Miller" wrote:

Some years ago, I formulated these rules of thumb. If a piece of any
significant size is out of
square, level, or plumb by...

1 part in 100 -- *immediately obvious* to a casual observer (don't
believe me? get a level
and check, the next time it's immediately obvious that a picture on
your wall doesn't hang
straight)

1 part in 200 -- apparent to anyone who is looking for flaws

1 part in 400 -- won't be seen, but can be readily found with common
carpentry tools (level,
tape measure, etc)

1 part in 800 -- can't be found without precision measuring tools

The significance of these rules is that the accuracy of your work
won't be any better than the
accuracy of the tools you produce it with (e.g. you can't get 1 part
in 800 results with a
"square" that measures 89.7 degrees).
----------------------------------------------------------------
Many on this list may not be old enough to remember the most useful
of all formulas:

"If a Flying Red Horse can't spot the difference from a thousand feet,
you're good to go".

Lew

wrote:
On Thursday, January 3, 2013 10:55:23 PM UTC-5, Doug Miller wrote:

What makes you think that? Do you own a set of feeler gauges?
I have never needed feeler gauges. They work on a very basic principle and I feel confident making that claim.

I bought a micrometer from Doug. When we measure, we don't food
around! : )