# So Here We Go.... Rules Or Scales



## rfdes (Apr 7, 2015)

I have seen alot of mixed information regarding this on the internet.  I'm professionally an electronics engineer and I've always understood that a rule measures absolute lengths while a scale is used for 'scaling' purposes.  Being a beginning hobby machinist, I keep hearing many machinists scolding others to always use the term 'machinist scale' as opposed to 'machinist rule'.

I guess it really doesn't matter one bit but I would like to know WHY it is referred to as a scale as opposed to rule?
Jim
Largo, Fl.


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## RJSakowski (Apr 7, 2015)

rfdes said:


> I have seen alot of mixed information regarding this on the internet.  I'm professionally an electronics engineer and I've always understood that a rule measures absolute lengths while a scale is used for 'scaling' purposes.  Being a beginning hobby machinist, I keep hearing many machinists scolding others to always use the term 'machinist scale' as opposed to 'machinist rule'.
> 
> I guess it really doesn't matter one bit but I would like to know WHY it is referred to as a scale as opposed to rule?
> Jim
> Largo, Fl.


Back in the sixties in high school drafting class we used scales.  If we referred to them as rule or rulers, we would get our knuckles rapped with one. We also got our knuckles rapped if we used them as a straight edge. Your explanation of the differentiation is very plausible.  Perhaps the old timers use the scale terminology because in those days, machinists got their prints from the draftsmen and the draftsmen only used scales. 

Haven't seen any tape scales lately!

Bob


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## Franko (Apr 7, 2015)

As far as I've seen there are two types of scales. Architect's scales in fractions and Engineer's scales in decimals, used for drawing scale drawings and plans.

As far as I know, and I've used rules and scales all my life, rules are for measuring length. Persnickety machinists need to lighten up and quit scolding people for silly stuff.


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## Tony Wells (Apr 7, 2015)

I am guessing here, but I think the term scale comes from the old days when mold makers used "shrink rules", which are used to scale up patterns to allow for shrinkage in the casting process. You can google for Starrett shrink rule and get more information. They are available in different ratios, or scales, according to need. 

In these parts, most machinists call them scales in general use. That's what I always heard, so that's what my habit is. I don't go around scolding people if they call them rules though. That is what Starrett calls them, and I figure they know a little about them.

There are also things called "Steel Rule Dies" which use what originally may have been someones flex-scale. But it was known as a rule at the time, hence the name. It's a useful thing to know how to make. There are prepared strips used in their making now.


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## Bill Gruby (Apr 7, 2015)

Call me "Persnickety" if you must, but when someone enters my shop, on the door are the rules. Number six states  you measure with a scale. Number seven says, "The above is  in English no metric".

"Billy G"


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## dracozny (Apr 7, 2015)

The only obscure difference I could find ~ "Machinist's rule: A multiple scale ruler used to measure distances or components that do not require precise measurement." So based on that I suppose we are trying to say a rule is less accurate than a scale. yet every dictionary I have says they are synonyms in this regard. If we are drawing on paper use what you got. the dimensions are often written down anyways. On the work use the appropriate tool for the job, often a Caliper for low tolerance and a micrometer for tighter tolerances.


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## MozamPete (Apr 7, 2015)

Back when I was a draughtsman, in the pre CAD days when we use ink and polyester sheets, a scale was a ruler the was was at other than 1:1.  If you had a drawing of a component that say had a detail drawn at twice life size (2:1) and you wanted to measure off the drawing you would use a 2:1 scale so you would be able to directly read the required dimension. You would never use a scale to measure anything in the "real" world. The real would is at 1:1 so you would use a ruler (or tape measure).


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## RJSakowski (Apr 7, 2015)

dracozny said:


> The only obscure difference I could find ~ "Machinist's rule: A multiple scale ruler used to measure distances or components that do not require precise measurement." So based on that I suppose we are trying to say a rule is less accurate than a scale. yet every dictionary I have says they are synonyms in this regard. If we are drawing on paper use what you got. the dimensions are often written down anyways. On the work use the appropriate tool for the job, often a Caliper for low tolerance and a micrometer for tighter tolerances.


The reference to scale in your quote refers to the different sets of divisions found on a machinists rule (1/8, 1/6, 1/50, etc.). As Peter said, a drafting scale is typically a three sided device with six different scales on it.  The scaling would be 1:1, 2:1, 10:1 so the draftsman didn't have to do any math to correctly draw.  I don't know specifically about the accuracy of a draftsman's scale but they were made of wood and there use was to make a reasonable facsimile of the required part so there was not a requirement for accuracy.  A machinists rule is usually made of stainless steel and is used to lay out machining work where there is a need for accuracy.  If I need accuracy, I would use the machinist's rule. 
Actually I haven't picked up a draftsman's scale in many decades even though I still have several.


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## uncle harry (Apr 7, 2015)

RJSakowski said:


> The reference to scale in your quote refers to the different sets of divisions found on a machinists rule (1/8, 1/6, 1/50, etc.). As Peter said, a drafting scale is typically a three sided device with six different scales on it.  The scaling would be 1:1, 2:1, 10:1 so the draftsman didn't have to do any math to correctly draw.  I don't know specifically about the accuracy of a draftsman's scale but they were made of wood and there use was to make a reasonable facsimile of the required part so there was not a requirement for accuracy.  A machinists rule is usually made of stainless steel and is used to lay out machining work where there is a need for accuracy.  If I need accuracy, I would use the machinist's rule.
> Actually I haven't picked up a draftsman's scale in many decades even though I still have several.



I also fondly remember the pre-CAD drafting days & scales.  Often a notation was made on a drawing "Do Not Scale" thus drawings weren't considered highly precise. (An exception would be polyester layouts done with higher quality drawing machines for layout verification).  Another notation often used was Not to Scale abbreviated as NTS.  More often than not it implied "Not too sure"!


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## randyc (Apr 7, 2015)

By "polyester" I suppose that "mylar" is meant.  Mylar became the standard for drawing stability rather than vellum paper, at least for the larger drawings that were produced at the Westinghouse Marine Division and other aerospace/defense companies where I was employed.

There was also a coated woven linen fiber medium that was very sturdy and superior to mylar for heat resistance but the coating could quickly be abraded away, especially with the electric erasers that became universal in the 'sixties.  I recall that by the late 'sixties, linen was being phased out.

Linen media, as I recall, was used primarily for inked drawings while mylar could be used for both ink and pencil.  The mylar drawing surface had a "tooth" - a roughened surface - so that graphite pencil lead would slightly abrade and imbed the particles that then constituted the drawing lines.

Linen media required that the surface first be treated using a fine powder called "Pounce" before inking.  The pounce slightly roughened the smooth coating on the linen so that it absorbed the ink.  (Without pounce, the inked lines would tend to "bead up" so continuous lines couldn't be produced.)

Old-timers may recall drafting pencil lead hardness classifications: for example, 5H was often used for construction lines, 4H for center lines and dimension lines and 2H for object lines and H for lettering.  There was also a product consisting of fine particles of rubber erasing compound contained in a cloth bag but I don't recall what we called it.

The bag was coarsely woven so that the particles could be released as the bag was squeezed and manipulated over the drawing.  The resulting fine particles were then lightly brushed over the surface of the pencil drawing with a drafting brush (another tool that has disappeared with the usage of CAD).  The purpose was to absorb the fine dusting of pencil graphite that inevitably spread over the drawing surface, to keep the drawing cleaner.

Man, does this thread bring back memories.  Here are a few manual drafting tools that I still own and sometimes even use, LOL.  There are also two Dietzgen compasses and a pair of dividers out in the shop that find occasional use.  In the center of this photo is a triangular architects _scale_.  This one is special because it was first used by my Dad then passed on to me.  The scale is approximately ninety years old.


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## RJSakowski (Apr 7, 2015)

randyc said:


> By "polyester" I suppose that "mylar" is meant.  Mylar became the standard for drawing stability rather than vellum paper, at least for the larger drawings that were produced at the Westinghouse Marine Division and other aerospace/defense companies where I was employed.
> 
> There was also a coated woven linen fiber medium that was very sturdy and superior to mylar for heat resistance but the coating could quickly be abraded away, especially with the electric erasers that became universal in the 'sixties.  I recall that by the late 'sixties, linen was being phased out.
> 
> ...


It does bring back memories.  I have not had any professional experience but I took 3-1/4 years of drafting in high school.  My intent was to go into drafting as a profession, which became diverted to engineering , followed by physics.  I used to work in the high school mechanical drawing department where I would run the whiteprint machine.  

The instructor moonlighted for various local firms producing their prints.  As I recall, the machine was about 6 to 8 ft wide.  You would start several of the inked transparencies on the roll and would have to cut the roll before it got pulled in.  We used a large pair of shears to cut the paper and would use a single swiping motion rather than the more traditional cutting motion..  Because of the darn mechanical drawing, I never did make it into the machine shop class or welding class.

I remember the 4H pencils.  I haven't seen one in years but you could really make some nice lines.  We did our inking with the split nib pens and old fashioned inkwell.  Different sized nibs for different line widths.


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## T Bredehoft (Apr 7, 2015)

The folding Lufkin product I carry in my hip pocket is a rule. The stainless, 12 in, item I have laying around so I can grab it when I want it is a scale. It has inches marked on it divided into different divisions, on one side fractions, on the other side tenths and hundredths of an inch. Just my opinion, not a "rule", meaning a regulation.

I've several of the metal ones (above), two start at 2" one a 1/2, it seems when you have them in your hip pocket and sit wrong, the end breaks off. Both sides start at zero on the same end, so I've become adept at reading from 12 down. None have broken at the 12 inch end.


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## uncle harry (Apr 8, 2015)

randyc said:


> By "polyester" I suppose that "mylar" is meant.  Mylar became the standard for drawing stability rather than vellum paper, at least for the larger drawings that were produced at the Westinghouse Marine Division and other aerospace/defense companies where I was employed.
> 
> There was also a coated woven linen fiber medium that was very sturdy and superior to mylar for heat resistance but the coating could quickly be abraded away, especially with the electric erasers that became universal in the 'sixties.  I recall that by the late 'sixties, linen was being phased out.
> 
> ...



Ah yes, linen. When I was a "rent'a grunt" (contract) drafter @ Allis Chalmers AEPD division near Milwaukee we used mostly linen.  AEPD built fuel cells for potential future use in the space race.  I have fond memories of those days. We did use graphite on linen then.  I had a lolly pop drawing machine on a 5 foot board working on a 7 foot layout for a MOL mass substitute model. MOL was the Manned Orbiting Laboratory project.  The model was an assembly of components and blocks of aluminum that represented the center of gravity for actual sub components.  These models went to Rockwell to determine the performance of an over all capsule model.
All of this ended when Apollo landed on the moon.


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## juiceclone (Apr 8, 2015)

MANY years ago, I worked with a Guy from Birmingham, England.  One of the many British term differences was,  a ruler was the King ... you measured things with a scale  (skiyul was his pronunciation)  :>))


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## Mark in Indiana (Apr 9, 2015)

I thought a rule was a law and a scale was that thing in your bathroom that tells how much by weigh. ;-)


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## RJSakowski (Apr 9, 2015)

When I think of scales, fish come to mind.


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## Alan Douglas (Apr 9, 2015)

I would suppose that a scale is for measurement, while a rule is for guiding something (tool, pen, pencil, or people).  But once you combine the two by adding graduations to a straight edge, it's simply custom that suggests which name to use.


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## T Bredehoft (Apr 9, 2015)

_ it's simply custom that suggests which name to use._ 

That's the answer we all need to observe.


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## stupoty (Apr 9, 2015)

I tend to use the term "measuring stick" for all my measuring implements.  Theirs a level of wrongness you cant get in trouble for, people just have to palm face at it. 

Stuart


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## kwoodhands (Apr 12, 2015)

Bill Gruby said:


> Call me "Persnickety" if you must, but when someone enters my shop, on the door are the rules. Number six states  you measure with a scale. Number seven says, "The above is  in English no metric".
> 
> "Billy G"



The only thing I measure with a scale is my fat butt.


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## Ulma Doctor (Apr 12, 2015)

to my knowledge, a rule(r) measures,
a scale is the representation of the measurement.


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## Bill Gruby (Apr 12, 2015)

If you were in a Trades School here in CT., I would not advise you to ask the Instructor for a Rule or Ruler. The word "Scale" is the only appropriate name.

 "Billy G"


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## markknx (Apr 12, 2015)

Well as I am just trying to get CAD figured out I still use A drafting scale. That said by the first definition given here A scale may not be a ruler, But a ruler could surely be used as a scale as in 1/2 " = 1"  I like to nag apprentices that call out dimensions like 35". I have to explain to them after 12" you use feet and inches unless you are going to sew the steel in place.  But I just do that to hack on them and get them used to using feet an inches, because 356" just sound so wrong.
Mark


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## toolroom (Jan 18, 2016)

O.K. O.K., A scale is something you keep in your apron pocket, ie. 6" scale, which is used for measuring, way scraping, stirring your coffee, eating your lunch with, as the house mouse forgot to pack a spoon, cleaning under your finger nails, and a host of other meaningful tasks! A rule, on the other hand is way too large for carrying around in your pocket, as you'd poke your eye out. Rules are used for lay out purposes only, and perhaps a rough measurement here and there!


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## turnitupper (Jan 18, 2016)

"Rules are for the guidance of wise men and the obedience of fools."  Douglas Bader.
Scales are eight keys on a piano.
John.


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## 4GSR (Jan 18, 2016)

I can vaguely remember when I was about ten years old, Dad brainwashing me that it is a scale and only a scale!

Remember when "blue linen" was the sacred of all Mylars?


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## BGHansen (Jan 18, 2016)

Here's a picture of a scale.  Mine is in graduation of 3/32, 3/16, 1/8, 1/4, 1/2, 1, 1 1/2 and 3 all scaled to 1".  Ironically, it is made by "The C-THRU RULER CO.".  Or is that the C-Thru scale company . . .

Bruce


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## kingmt01 (Jan 18, 2016)

markknx said:


> Well as I am just trying to get CAD figured out I still use A drafting scale. That said by the first definition given here A scale may not be a ruler, But a ruler could surely be used as a scale as in 1/2 " = 1"  I like to nag apprentices that call out dimensions like 35". I have to explain to them after 12" you use feet and inches unless you are going to sew the steel in place.  But I just do that to hack on them and get them used to using feet an inches, because 356" just sound so wrong.
> Mark


I prefer for measurements to be called out in inch. I refuse to let it slide if I'm working with someone that calls out such a number as 10' 3" & 3/32 of a inch when I'm cutting a brace. I use feet when a few inches doesn't matter. everything else is measured in inch usually down to an 1/8". It wasn't until I took up the hobby of machining I started using tenths, hundredths, thousandths , & ten thousandths.

As far as a scale or ruler goes. I remember as a kid in my uncles shop he called it a steel measure. This actually sounds the most correct to me. The measure is scaled into tenths & such.


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## FOMOGO (Jan 18, 2016)

randyc said:


> Old-timers may recall drafting pencil lead hardness classifications: for example, 5H was often used for



 Just watch who your calling old timer there buddy. I still have a desk drawer full of scales, pencils, and all the other drafting paraphernalia used for drawing house plans back in my general contractor days. Sold the drafting table years ago so I'd have more room in the shop. When it's all said and done I guess call it what your comfortable with, just don't call me late for dinner. Mike


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## wawoodman (Jan 19, 2016)

"stick rule" is right up there with "ink pen."


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## middle.road (Jan 19, 2016)

So anyway, have we figured out yet what purpose the little black hash/tick/graduation lines/marks serve?


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## doogledee (Jan 19, 2016)

Huh I learn something everyday. 
I would call the straight bit a ruler, and the markings on it the scale.
On a caliper or micrometer there is a scale as well, but not a ruler. At least in my book that is the eay I think about it.

My lathe and mill both have scales on the handwheels.
On a dro the scles are so fine I need a reading head to interpret them and write the values on a display for me....

Just my thoughts.... Probly not correct or something....



Sent from my iPhone using Tapatalk


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## Forty Niner (Jan 19, 2016)

Based on a few years (40) in machine shops, the accepted name for the 6" flat steel measuring device in a machinist's pocket was and is "scale".  Never rule or ruler.


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## kvt (Jan 19, 2016)

I still have the T square, I even still have a bottle of ink, and the old set that you use it in.  I use to hate the old thin tracing paper, and heaven forbid that you hit a pin hole with the ink.  I also have a set of the newer but still old  refillable pens that you used.   Problem is I have not gotten decent on CAD,  so I still pull them out to make a drawing when needed.    I guess I should learn the new stuff.    
You had stuff that was supposed to be drawn to scale 1:1 then you had stuff that was either enlarged 2 to 1 etc, or the stuff that downsized to 1 to 10  or something.   Depending on what you ware drawing was what scale you used.  A ruler was what the rest of the school used to call the wooden thing they used to measure stuff for projects.   Of course wood shop used a tape measure.


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## joshua43214 (Jan 19, 2016)

hmmm
I always thought scale was that stuff on the outside of hot rolled that dulls tools.
Rules of course are things meant to be broken.

So much to learn...
Funny how the thing we put in out pocket is called a "scale," but the moment you put a tab on the end of it, it morphs into a "hook rule."

The ruler of Scales, England often used a ruler to discipline the ruled for failing to follow the rule prohibiting scaling the scale model of a scale. Scaling the ruler has been found to be an effective way to scale the punishment to fit the scale of the misdemeanor. The practice was abandoned when it was discovered that using a scale to weigh the scale of the ruler was improper because a balance is the proper tool for weighing. Discipline is now ruled out for the ruler, and is left to retired nuns who understand proper use of scaling and ruling.


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## kingmt01 (Jan 19, 2016)

Give me a few minutes to scale through that & see how it measures up. Then I'll weigh in with a rulling if it all balances out.


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## Bill C. (Jan 19, 2016)

We use rulers, whether they are 6"or 12" or 24" long.

Draftsman use scales, they are about 12" long and three sided.


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## Techie1961 (Jan 19, 2016)

I have been in this stuff since way before CAD and did a fair bit of paper and machine work. I was always taught that you can draw lines with a ruler (it can also have measurement marks on it) and you never drew a line with a scale, it was used to measure things whether the scale was 1:1 or 1:100 and so on.


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## uncle harry (Jan 19, 2016)

Techie1961 said:


> I have been in this stuff since way before CAD and did a fair bit of paper and machine work. I was always taught that you can draw lines with a ruler (it can also have measurement marks on it) and you never drew a line with a scale, it was used to measure things whether the scale was 1:1 or 1:100 and so on.



Drafting machine SCALES were 12, 18 & sometimes 24" L. Aluminum or plastic. They were used to efficiently draw lines on their edges. The were available in several  "scales".


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## 4GSR (Jan 19, 2016)

uncle harry said:


> Drafting machine SCALES were 12, 18 & sometimes 24" L. Aluminum or plastic. They were used to efficiently draw lines on their edges. The were available in several  "scales".


Used to have around 12 pairs of scales for my Vemco X-Y drafting machine. Always wanted the Kroy lettering machine to go with it, too.


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## Tony Wells (Jan 20, 2016)

Perhaps the poll is not very clear, but someone did not vote correctly. You can change your vote if you made a mistake,


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## planeflyer21 (Jan 20, 2016)

There's an option on the poll missing.

Around here the scale is the thing that puts the ruler in a bad mood.


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## Tony Wells (Jan 20, 2016)

Sorry, not machining related.


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## Grumpy Gator (Jan 20, 2016)

_In the 40 odd years I'v been around machine shops and machinist I have never meet one that didn't have a 6" scale in his pocket._
_I have always thought it was called a "scale" was because on the back side there is a "Decimal Equivalents" scale._
_****Just Saying**********Gator************_


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## eugene13 (Jan 20, 2016)

I've always used the term scale, and I had a half-wit supervisor where i used to work who thought it was a scraper.


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## wawoodman (Jan 20, 2016)

To me it's a rule or a ruler. But remember, I come from a woodworking background.


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## Firestopper (Jan 21, 2016)

I was taught back in HS (78-81) that 6" machine ruler is referred to as "scale" I call anything longer a ruler, but probably incorrect.


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## hermetic (Jan 21, 2016)

In the UK a 1:1 measuring stick is called a rule in engineering, be it a 6" top pocket model, or a larger size, A scale rule is used to convert a scaled drawing to real world 1:1 or to produce such a drawing. The clue is in the use of the word scale, or scaled, as in scaled up or scaled down. If it is 1:1 it is not scaled. what we have here is two different usagtes on two different sides of the Atlantic.
Phil


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## rick9345 (Jan 21, 2016)

guesstimater covers both as does "Let me use that thing y in my pocket to check." Or we could just check with "Miss Manners" for proper usage.


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## Tony Wells (Jan 21, 2016)

But Phil, 1:1 is full *scale*, yes?

Besides, we are talking (mostly) about the things you carry in your pocket. I personally also carry a 12" hook scale in my back pocket and it sometimes gets used as a chip hook.......wonder what I should call it.


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## hermetic (Jan 22, 2016)

yes, it is full scale, and i have to admit i don't know what a hook scale is!


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## Bill Gruby (Jan 22, 2016)

Phil;

 This is a hook scale.  http://www.ebay.com/itm/NEW-STARRET...376092?hash=item2eeac68bdc:g:xfAAAOSwUV9Wnx8h

 "Billy G"


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## Eddyde (Jan 22, 2016)

Bill Gruby said:


> Phil;
> 
> This is a hook scale.  http://www.ebay.com/itm/NEW-STARRET...376092?hash=item2eeac68bdc:g:xfAAAOSwUV9Wnx8h
> 
> "Billy G"


It is a hook rule, or a rule with hook, according to the maker:
http://www.starrett.com/metrology/m...isplayMode=grid&itemsPerPage=24&sortBy=wp/asc

If the almighty Starrett company calls it a Rule, that's good enough for me.


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## mws (Jan 22, 2016)

I've always considered "scale" to refer to a fixed  mathematical relationship to another known standard. For instance; the "scales" on your hand wheels may be marked for 0.001" increments but are 0.050" apart, or a scale drawing. 
A "rule" is a tool for marking off fixed increments or lines, either using a scale or an actual fixed measurement standard.  In the latter case it becomes a "ruler". 
Just my take on things. I'm also in electronics and spent much of my career calibrating laboratory equipment. Given all my time dabbling in things "metrological" I can't remember getting into the rule, scale, ruler debate ever. Guess it all seemed fairly obvious at the time.


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## hermetic (Jan 22, 2016)

Thanks Bill et al, I don't think I have seen those this side of the pond, I will have a poke about!
Phil


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