PDA

View Full Version : Measurement check please



Dee Gallo
05-04-2010, 7:32 AM
It drives me crazy that some companies use inches, some mm and some decimals. I made myself a small chart, can someone please confirm if I got it right? I am math challenged...

1/8" = 0.125 = 3.175
3/16" = 0.188 = 4.763
1/4" = 0.250 = 6.350
3/8" = 0.375 = 9.525
1/2" = 0.500 = 12.700

This might be helpful to other people with my problem too :)

thanks, dee

Scott Shepherd
05-04-2010, 8:02 AM
It's pretty close Dee. You can get pretty close by using the number 25.4.

English .125" multiple by 25.4 = 3.175mm.
Metric 3mm divide by 25.4 = .118"

That'll get you pretty close. It's not a perfect calculation but it's close enough for anything we'll ever do.

David Fairfield
05-04-2010, 8:56 AM
Hey Dee

Check out this bad boy. For $25 you get an extremely precise caliper, plus a digital readout that can flip between fractions, decimals, inches and mm, all at the push of a button. I use a caliper constantly in my work, one of my most used tools.

http://www.micromark.com/FRACTIONAL-DIGITAL-CALIPER,8797.html

When it comes to math, I'm all for replacing mental skills and comprehension with a cheap calculator :D

Dave

Doug Lynch
05-04-2010, 8:59 AM
Two things here that may help. First download a free program (I have been using it for years) called “Convert” from http://joshmadison.com/software/convert-for-windows/ (http://joshmadison.com/software/convert-for-windows/) it is really good and free. (NASA even uses it on the ISS)
Second in Corel I learned something from Roy Brewer (Thank you) when entering a length or width in that box at the top of the screen you can enter it like 0.125 or .125 or 1/8 Corel will take care of the rest. Need to enter 2 5/6” you can do it 2 (space) 5/16 enter or 2.3225 enter. You can also switch back and forth from metric to English in Corel.

Doug Lynch

Scott Shepherd
05-04-2010, 9:04 AM
You can also type in 10mm in the boxes for the length and width of things. Corel will convert it for you.

Paul Brinkmeyer
05-04-2010, 9:26 AM
I second both items

I have used convert for years, very easy.
The Corel feature works good too, and you can put equations in the size or location field as well.
Like 6.25/2 (6.25 divided by 2)
works like a charm





Two things here that may help. First download a free program (I have been using it for years) called “Convert” from http://joshmadison.com/software/convert-for-windows/ (http://joshmadison.com/software/convert-for-windows/) it is really good and free. (NASA even uses it on the ISS)
Second in Corel I learned something from Roy Brewer (Thank you) when entering a length or width in that box at the top of the screen you can enter it like 0.125 or .125 or 1/8 Corel will take care of the rest. Need to enter 2 5/6” you can do it 2 (space) 5/16 enter or 2.3225 enter. You can also switch back and forth from metric to English in Corel.

Doug Lynch

George Brown
05-04-2010, 9:47 AM
I keep this chart handy. I can never remember the decimal equivalents. Some software, unlike Corel, does not convert automatically.

Michael Hunter
05-04-2010, 9:54 AM
Scott

Your multiply/divide by 25.4 isn't just pretty good - it is EXACT!

The inch is defined as 25.4mm (standardised by both USA and UK in 1959 according to Wikipedia).

I use an on-screen "gadget" calculator which is handy, but the conversion by Corel is good too.

Andrea Weissenseel
05-04-2010, 9:58 AM
Don't know if that works for you, but I have turned on the google translation feature and as soon I point the mouse on a inch measurement it directly shows me the mm equivalent. Other than that, I also use Corel and just type in inches, which turns automatically into mm because german is selected in my Corel

Andrea

Dee Gallo
05-04-2010, 10:57 AM
Wow, you guys, thanks for all the suggestions! You do realize that I try to avoid doing any math at all costs... but Scott you really simplified it for me.

Thanks everyone, dee

Dee Gallo
05-04-2010, 11:02 AM
I keep this chart handy. I can never remember the decimal equivalents. Some software, unlike Corel, does not convert automatically.

Thanks for this George, I've printed it out and will keep it with me when I go to the store... my local Borgs use inches sometimes and decimals sometimes, I never know what to get! I've taken to carrying a small tape measure with me at all times now.

:) dee

Dan Hintz
05-04-2010, 11:03 AM
Scott

Your multiply/divide by 25.4 isn't just pretty good - it is EXACT!

Beat me to it...

Lee DeRaud
05-04-2010, 11:20 AM
I second both items

I have used convert for years, very easy.
The Corel feature works good too, and you can put equations in the size or location field as well.
Like 6.25/2 (6.25 divided by 2)
works like a charmThird that. The place I seem to use it the most is in the rotation angle field, e.g. "360/16".

Steve Kelsey
05-04-2010, 11:24 AM
I second both items

I have used convert for years, very easy.
The Corel feature works good too, and you can put equations in the size or location field as well.
Like 6.25/2 (6.25 divided by 2)
works like a charm

another great corel feature. I've been doing the math the whole time!

Scott Shepherd
05-04-2010, 12:05 PM
Scott

Your multiply/divide by 25.4 isn't just pretty good - it is EXACT!

The inch is defined as 25.4mm (standardised by both USA and UK in 1959 according to Wikipedia).

I use an on-screen "gadget" calculator which is handy, but the conversion by Corel is good too.

I worked for a UK based company for many years, everything was metric. We always used .03937 as the figure to convert and there were large debates between engineers about us not using 25.4 because at some point it lost some accuracy.

I never knew the details, I just recalled it being a big issue in a very big company for a long time, so I just always used .03937.

Lee DeRaud
05-04-2010, 1:30 PM
I worked for a UK based company for many years, everything was metric. We always used .03937 as the figure to convert and there were large debates between engineers about us not using 25.4 because at some point it lost some accuracy.

I never knew the details, I just recalled it being a big issue in a very big company for a long time, so I just always used .03937.25.4 is good to at least four decimal places relative to your 0.03937: 1.0/0.03937 = 25.4000508.
If you need more accuracy than that, you shouldn't be converting, period: just pick a unit and stick with it.

Frank Corker
05-04-2010, 2:10 PM
Dee I'm not sure if you are aware of this, but in Corel, you can add any figure that you want into the measurements, even if you are working in mm, cm or ".

Say your settings are for 11.0" - in the box shown below, after the " type in +5mm and it will automatically add and convert it for you. Try it, works for me!

Works the other way too, if you are working in millimetres and after the mm you type in +3/8" it will convert the 3/8" and add it to the figure.

Michael Hunter
05-04-2010, 2:12 PM
1" = 25.400000 mm by definition (or at least international agreement).

I think that the problems arose because of CAD systems : in order to be able to display drawings (and particularly printed circuit board layouts) in both metric and imperial units, the positional databases of the programs often used a very tiny number (common divisor? [I'm not a mathematician]) that could be multiplied up to give either set of units. Back in the 80's (when I became aware of the problem) our American PCB design software gave a minute error when told to display in mm : over a big PCB (10" or more) the error could add up to make a visible difference and cause things to not-quite-fit.

In those days, floating-point machines were not so good (remember the fuss about Intel processors getting sums wrong?) and memory was measured in k rather than G. So they fudged the common divisor.
I think that with the current computing power available to all, the problem has "gone away", with the conversions being calculated properly.

Dee Gallo
05-04-2010, 3:12 PM
Dee I'm not sure if you are aware of this, but in Corel, you can add any figure that you want into the measurements, even if you are working in mm, cm or ".

Say your settings are for 11.0" - in the box shown below, after the " type in +5mm and it will automatically add and convert it for you. Try it, works for me!

Works the other way too, if you are working in millimetres and after the mm you type in +3/8" it will convert the 3/8" and add it to the figure.

Thanks, Frank - I did know about the conversion feature in Corel. I was more asking about ordering from different companies, like Delvies uses inches and ePlastics uses decimals, so when I want to order something a specific size or comparison shop, I have to figure out what is what.

You guys are WAY too into this math stuff!

:D dee

Chuck Stone
05-04-2010, 6:59 PM
You guys are WAY too into this math stuff!

:D dee

"Nobody likes a math geek, Scully"
Fox Mulder - X Files

Mike Chance in Iowa
05-04-2010, 10:09 PM
I too agree with the above statements that using Corel to do the math for you is so simple and easy. While I have my Corel set up to default to inches, there are often times I have to create an object based on metric measurements given to me. Instead of using a conversion program, I simply type the desired data. For as a rectangle that is 256.5 mm long, I type 256.5mm (no need for the space) in appropriate "object size" field in the toolbar and as soon as I press Enter, Corel converts it to 10.098" for me.

I received a business card years ago that is a conversion table for fractions & decimals. VERY handy to have when shopping. (Especially for those of us who do not have decent cell coverage for an iphone or similar gadget.) I used it so much that I created a easy-to-read poster for above my desk and use it practically daily. (Why I don't have these conversions committed to memory by now is something I ponder frequently!:o)

Earl Cox
05-05-2010, 10:58 AM
If you know the mm, and want to find inches, multiply the mm by .03937 to get inches. If you know the inches, divide by .03937 to get the mm.

Lee DeRaud
05-05-2010, 11:02 AM
If you know the mm, and want to find inches, multiply the mm by .03937 to get inches. If you know the inches, divide by .03937 to get the mm.Because 0.03937 is easier to remember than 25.4? :confused:

Dan Hintz
05-05-2010, 11:41 AM
Because 0.03937 is easier to remember than 25.4? :confused:
Or more accurate? :confused:

Lee DeRaud
05-05-2010, 12:21 PM
Or more accurate? :confused:I thought we already laid that to rest: see post #18.

The only way I can see 0.03937 is "better" than 25.4 is that you can use it to (approximately) convert mm to inches by multiplying rather than dividing.
And that advantage is virtually nonexistent on modern computers.

Frank Corker
05-05-2010, 2:56 PM
I thought we already laid that to rest: see post #18.

The only way I can see 0.03937 is "better" than 25.4 is that you can use it to (approximately) convert mm to inches by multiplying rather than dividing.
And that advantage is virtually nonexistent on modern computers.

We probably did, but this way we can draw it out for another 234 posts!

George Brown
05-05-2010, 3:51 PM
I personally like to use 11111110 :eek:

George Brown
05-05-2010, 3:59 PM
Thanks for this George, I've printed it out and will keep it with me when I go to the store... my local Borgs use inches sometimes and decimals sometimes, I never know what to get! I've taken to carrying a small tape measure with me at all times now.

:) dee


I like a woman who goes shopping prepared!!:D

Lee DeRaud
05-05-2010, 4:04 PM
I personally like to use 11111110 :eek:Heh. I recall a rather "lively discussion" on rec.woodworking some years ago, wherein someone claimed that "The metric system is more accurate because you don't have all those halves, quarters, eighths, and sixteenths: everything divides by ten, just like in a computer." :cool::p

Norberto Coutinho
05-05-2010, 7:05 PM
In portuguese, but I think you can find in english
.
http://pt.wikipedia.org/wiki/Sistema_Internacional_de_Unidades
.
and I just found this in the site
.
http://www.imperialtometric.com/

Dan Hintz
05-05-2010, 7:17 PM
Lee,

I was agreeing with you...

Kim Vellore
05-05-2010, 7:56 PM
Because 0.03937 is easier to remember than 25.4? :confused:

to contribute my $1/50 to this thread because

1/.03937 = 25.400050800101600203200406400813 which will give you a number close to the exact...

Kim

Dee Gallo
05-05-2010, 8:24 PM
AAAAAAACCCKKK! :eek: This thread hurts my brain...who is the idiot who started it? Oh, that would be me, sorry. :o dee

George Brown
05-05-2010, 8:43 PM
to contribute my $1/50 to this thread because

1/.03937 = 25.400050800101600203200406400813 which will give you a number close to the exact...

Kim


Actually it is 1/0.03937007874015748031496062992126 = 25.4 :o

Larry Bratton
05-05-2010, 8:47 PM
Maybe a firm grasp of the obvious, but to convert fractions to decimals, simply divide it, in other words divide 1 by 8 (1/8) = .125 etc. Surprising how many people don't know that.

George Brown
05-05-2010, 8:54 PM
AAAAAAACCCKKK! :eek: This thread hurts my brain...who is the idiot who started it? Oh, that would be me, sorry. :o dee


You shouldn't start us going on this math thing. Some of us actually enjoy the torture! :eek:

Dan Hintz
05-06-2010, 6:32 AM
AAAAAAACCCKKK! :eek: This thread hurts my brain...who is the idiot who started it? Oh, that would be me, sorry. :o dee
Tomorrow's lesson will be on multi-dimensional Gaussian probability graphs and partial differential equations for heat transfer into a substrate.

:p I hold a love/hate relationship with higher maths...

Lee DeRaud
05-06-2010, 9:39 AM
Tomorrow's lesson will be on multi-dimensional Gaussian probability graphs and partial differential equations for heat transfer into a substrate.

:p I hold a love/hate relationship with higher maths...You know you're a math groupie when you have an autographed copy of NFL quarterback Frank Ryan's PhD dissertation, "A Characterization of the Set of Asymptotic Values of a Function Holomorphic in the Unit Disc". I never understood why someone would abandon a promising career in math to throw around a prolate spheroid for a living.:eek:

George Brown
05-06-2010, 10:03 AM
You know you're a math groupie when you have an autographed copy of NFL quarterback Frank Ryan's PhD dissertation, "A Characterization of the Set of Asymptotic Values of a Function Holomorphic in the Unit Disc". I never understood why someone would abandon a promising career in math to throw around a prolate spheroid for a living.:eek:


Because with math you can only fantasize about the numbers, throwing about the spheroid, you can take it to the bank! :D

George Brown
05-06-2010, 10:08 AM
Tomorrow's lesson will be on multi-dimensional Gaussian probability graphs and partial differential equations for heat transfer into a substrate.

:p I hold a love/hate relationship with higher maths...


In a previous incarnation, I actually enjoyed solving differential equations! Maybe that is what fried my brain? :(

Dee Gallo
05-06-2010, 10:11 AM
Tomorrow's lesson will be on multi-dimensional Gaussian probability graphs and partial differential equations for heat transfer into a substrate.

:p I hold a love/hate relationship with higher maths...

Okay, Dan, now you're just making up words that make no sense...:mad::mad:

Dan Hintz
05-06-2010, 10:36 AM
George,

Coolest math thing I ever learned? While taking a course on hyperspectral image processing, I learned that as the dimension of a multi-dimensional Gaussian distribution increases, the bulk of the data actually moves to the tails, not the center as intuition would suggest.

For the (semi-)layman: Look at a Gaussian distribution curve (the ol' Bell Curve from school)... the majority of the data is in the middle. Now make it in two dimensions... it looks like a sombrero, but the majority of the data is still in the middle 'hump'. Keep increasing the dimension to 3D, 4D, etc... as it increases, the data actually begins to shift to the tails. Freaky, unintuitive, but mathematically provable.



And Dee, I never joke when it comes to math... math has no sense of humor, so it's pointless to try and make it laugh :p It nearly cost me my sanity in grad school! And should anyone else think I make this stuff up, here's the generalized diffusion equation: :D
http://upload.wikimedia.org/math/5/1/3/5138b72185154cb14d34447146f018e3.png

Lee DeRaud
05-06-2010, 11:16 AM
Keep increasing the dimension to 3D, 4D, etc... as it increases, the data actually begins to shift to the tails. Freaky, unintuitive, but mathematically provable.If you were really good, you'd do a drawing of that in Corel.:cool:

There, back on topic...can I go now?

George Brown
05-06-2010, 11:20 AM
http://upload.wikimedia.org/math/5/1/3/5138b72185154cb14d34447146f018e3.png


Brings back fond memories! :(:(

Frank Corker
05-07-2010, 2:46 AM
Brings back fond memories! :(:(

You do realise you're all NERDS

Dan Hintz
05-07-2010, 6:18 AM
You do realise you're all NERDS
Can't speak for the others, but I'm a geek... nerds have no social skills :D

Know how to tell an extroverted engineer? He looks at your shoes when he talks to you...

George Brown
05-07-2010, 1:12 PM
You do realise you're all NERDS


Someone has to develop all the software and high tech stuff everyone takes for granted :D.

Belinda Williamson
05-07-2010, 1:34 PM
All these smart guys and their big equations . . . makes my head ache, too. Hey Dee, how about we take your chart and go shopping for something to ease our headaches? After reading this thread I'm not sure I can calculate a tip for the bartender. :D

George Brown
05-07-2010, 1:38 PM
mudslides !!!!

Scott Shepherd
05-07-2010, 2:03 PM
Appletini's for all the geeks!!!!! :p

Dan Hintz
05-07-2010, 2:21 PM
Don't knock the Appletini, man... them things rock! :p

Dee Gallo
05-07-2010, 2:30 PM
All these smart guys and their big equations . . . makes my head ache, too. Hey Dee, how about we take your chart and go shopping for something to ease our headaches? After reading this thread I'm not sure I can calculate a tip for the bartender. :D

Heck, I can't even remember why I asked the question now...:D

Michael Kowalczyk
05-07-2010, 2:41 PM
Hey Dee

Check out this bad boy. For $25 you get an extremely precise caliper, plus a digital readout that can flip between fractions, decimals, inches and mm, all at the push of a button. I use a caliper constantly in my work, one of my most used tools.

http://www.micromark.com/FRACTIONAL-DIGITAL-CALIPER,8797.html

When it comes to math, I'm all for replacing mental skills and comprehension with a cheap calculator :D

Dave
Hey Dave,
I have about 6-7 of them around the shop at each CNC, laser, office pc. Found some similar to the one you show for around 12.00 (forgot where I got them about 7-8 years ago... just have to replace battery every year or so) then found some plastic ones on sale for around 6.00 at harbor freight. only 2 digit accuracy but for a laser it works great.

you can never have too many tools:D well almost never.

Andrea Weissenseel
05-07-2010, 3:11 PM
that's why I do most of my shopping over internet - google knows it all :D

George Brown
05-07-2010, 3:28 PM
Heck, I can't even remember why I asked the question now...:D


Bet you're sorry you did! :D

David Lampitok
05-07-2010, 5:57 PM
Dee,This keeps my brain from exploding .Also you have a mac so Art directors toolkit should be in your apps folder (may be in utilities)

David Lampitok
05-07-2010, 6:04 PM
Slow Upload speed....

Dee Gallo
05-07-2010, 7:23 PM
David -

I'm running 10.5.8 - but I don't see anything called art directors tool kit, even with find file. But I think I have enough info on this for now...hahaha...more than enough!

Thanks everyone for all the "help". I have to go to math therapy now.

:) dee

David Lampitok
05-08-2010, 12:39 PM
Are we running one of those "Illegal Math Labs" I see on the news?



http://www.code-line.com/software/maczot/artdirectorstoolkit5/movie/

Dan Hintz
05-08-2010, 1:46 PM
It could lead to a high(er learning curve)...