Not logged inAmerican Welding Society Forum
Forum AWS Website Help Search Login
Up Topic Welding Industry / Welding Fundamentals / Decimal to fraction conversion
- - By aevald (*****) Date 08-09-2006 18:58
Hi Folks, many times when I am involved in figuring out a specific layout type of problem, I have needed to convert inch/decimal type answers to feet,inch/fraction type answers. A relatively simple way that this can be done is as follows: In the case of a number such as 312.468, the first step of the conversion would be to divide the number by 12. When you have done this you will get the following answer, 26.039, the whole number portion of this answer(26), is the number of feet in the answer. In the next step, subtract the 26 from the number, this leaves .039. Now multiply the .039 by 12, this step will yield the number of inches in the conversion, the answer is 0.468, since the number to the left of the decimal is 0 there are no whole inches in this particular number. In the final step determine the denominator that you would like the fraction to be(8, 16, 32, etc.) use this number as your multiplier and multiply the .468 by that number, in this case I,ll use 16. After I have multiplied .468 by 16 the answer is 7.488, since the whole number is 7 and the decimal value left over is less than .5 I will use the 7 and place it over 16 making the fraction 7/16's. If the decimal left over had been greater than .5 I would have rounded up the whole number, but not in this case. So when the conversion is done your answer is 26'-0 7/16". I almost forgot, a scientific calculator definitely makes this process a whole lot easier. Hope some of you can use this out there. Regards, aevald
Parent - By jwright650 (*****) Date 08-09-2006 20:25
Good tip aevald,
Many contract drawings used decimals of a foot, a "Jobber" or "Construction Master" calculators have these functions built in to make this an easy conversion.
Here is a link to the Jobber...that is the calculator that I use on a daily basis, so I can vouch for how well it works and is easy to use.
http://www.jobbercalculator.com/
Parent - - By yorkiepap (***) Date 08-11-2006 03:20
Hi aevald,
Just a comment regarding your post and the need for our education system to get back to the old school method of teaching math. I see the majority of youngsters today have no idea how to use the fractional/decimal system to measure. Heck, most have a hard time reading a simple rule graduated to the 32nd. Make me understand how these youngsters are supposed to function in the trades world where everything is based on our numerical system. Do they carry their scientific calculator in their toolbelt?

Denny
Parent - - By aevald (*****) Date 08-12-2006 06:19
Hello Denny, I certainly know where you are coming from. I teach a fabrication and layout class along with various welding courses and related classes as part of the curriculum for the welding department and education in general. I run into people all day long of various ages and life experiences that have great difficulty doing even basic math and knowing how to read a rule, micrometer, etc. The reason that I suggested a scientific calculator in my post has to do with the many other uses that a tool such as that can be used for. You could certainly use the formula that I gave and do it longhand without a calculator, yet, it would take a lot of paper and a lot of extra time that you might not be afforded on the job. Right angle trigonometry could also be done longhand, however, most people would not want to have to carry a table of tangents, cotangents, sines, and cosines just to be able to do those formulas. Actually, I do keep a scientific calculator among the tools that I bring to the job with me. I try to stress applied mathematics, meaning math that can be used and be seen as valuable and tangible. The use of a calculator is only brought into play to help cut down on the amount of time required for some of the more complex formulas and equations that can be utilized in layout and fabrication areas. I have done a great amount of fabrication and layout using conventional and traditional methods as I believe you are talking about and I have also used methods that have been derived by the use of scientific calculators or cad systems, in either case the bottom line is to get the job done correctly and in the least amount of time as possible. I try to stress the use of both of these methods as they are available, if you don't have the cad system or scientific calculator then use the conventional method, but if you do have access to the advanced method and it will save you time, use it. Best regards, aevald
Parent - - By jwright650 (*****) Date 08-12-2006 10:26
Guys,
I know exactly where both of you are coming from with regards to the use of a calculator. I agree that some use it as a crutch while others use it for convenience. I had came from a structural detailing background before I was introduced to the shop aspect of this trade, so I have some experience of both sides of the fence. While I knew how to figure many problems that arose in the shop for our fitters by long hand math/trig, I found myself with a headache after a few hours of figuring these things longhand(ie. detailer gave the middle-ordinate and radius on a piece of rolled material that was rolled to a 90ft radius. The fitter was trying to see if he had rolled it correctly all along the circumference, so I proceeded to figure what this radius picked up at 2'-0 intervals...longhand. After several of those with a few hours, I decided I would bring in my "Jobber" calculator from home, and then it was just a matter of entering the radius, and the mid-ord, and asking the calculator for the other points. Same with working right triangles, feed in what you know about the triangle or circle and let the calculator figure the rest. Definately a time/headache saver. Of course it does raise an eyebrow when a fitter asks you to help figure these things and you have soapstone scribble all over their work before you end up with the answers...LOL
Parent - By CHGuilford (****) Date 08-15-2006 10:02
All good points.  Unfortunately, we can't force anyone to learn if they don't want to.  Many of our fitters are knowledgeable in the formulas needed for fabrication work.  Some have not learned for whatever reason, but when people ask questions, we know they want to learn.  I always try to show what the formula is and why it solves the problem.  I figure, rather than show which buttons to press on the calculator, show why those numbers are being entered.  They might not remember all of it the next time they need it but if there is an interest, they will catch on.
Parent - - By yorkiepap (***) Date 08-15-2006 01:16
Aevald & John Wright,

I do agree with both of you regarding the multitude of applications that math has to be utilized and the easiest methods to acquire them. I have no problem using a calculator for those calculations. I simply was referring to the number of youngsters I have encountered throughout my working career who have a very difficult time with fractional and decimal equivalents. And so many cannot read a simple scale to the 32nds. When I asked them why they had such difficulties, 99% replied they weren't taught how do conversions the old way. And algebra.....Duuuuuuhhhhh.

Anyway, I did not mean to infer that calculators did not have their place in the work environment.....Denny
Parent - By jwright650 (*****) Date 08-15-2006 10:31
Denny,
I hear ya....concerning the young people and what they didn't get in grade school or high school, yet graduated, is a black eye on our school systems. I can think of at least two people in my shop that can not read anything over a 1st or 2nd grade level and they are my age(41). I'm not talking about someone who quit school to go to work and help take care of their family. They both graduated from a county highschool nearby. One of these guys works in our detail material department. We kept getting plates in the shop that were cut short and finally I asked one day for one of these guys to show me 1'-3 7/8" on his tape line, because it is very different from mine. I realized that day, when he told me there must be a hundred of those little marks in an inch, we had some problems to work out. He is doing alot better now(15 years later and a lot of coaching), about reading his tapeline.
Parent - By aevald (*****) Date 08-15-2006 15:54
Hello again Denny, I have run into those same individuals to one degree or another over the course of my teaching and welding/fabrication career. I constantly try to stress to individuals the importance of basic mathematics and how they can simplify their everyday experiences with a good understanding and application of math. Through various examples of application that can be seen as valuable, it is easier for individuals to grasp the concepts and the funny thing is when you tell them that they just applied right-angle trigonometry, pathagorean theorem, or other complicated sounding formulas they look you with that dumb-founded look as if to say " so that's what they meant in my math class, they sure didn't explain it that way". I can understand anyone's frustration when dealing with individuals who don't appear to have even a basic grasp of many of the things that seem to be common sense and should be commonplace. Part of the reason why I spend time on this forum is to find new ways of looking at common and uncommon subjects and various points of view, it has been educating me from the very first time I started reading the various posts and comments. Thanks for your take, Denny. Regards, aevald
Parent - - By RonG (****) Date 08-25-2006 20:11
26' 15/32". Most of my work when stated in decimal I am only allowed +/- .005"
Parent - - By turbo38t (*) Date 10-05-2006 00:55
aH, IF ONLY US smart aMERICANS USED THE METRIC SYSTEM......SO SMART....SO SIMPLE......10  X 10 X 10......HOW HARD IS IT TO MULTIPLY BY 10S?
Parent - - By RonG (****) Date 10-12-2006 15:25
Shucks, then any body could do it, wheres the challenge?
Parent - - By swnorris (****) Date 10-12-2006 18:11
In spite of the simplicity of fractions, did you know that 5/4ths of all the people in this country still have problems with them? I mean, I can generally get along with everybody, but there's three kinds of people that I absolutely just cannot tolerate: those who can count, and those who can't.   
Parent - By RonG (****) Date 10-12-2006 20:16
Yea I hear ya, I have to get in the shower to count to 21. 5/4's is that any thing like 4 Fries short of a Happy Meal?
Up Topic Welding Industry / Welding Fundamentals / Decimal to fraction conversion

Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill