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I am going over all math subs. What are some common carpentry math that you could tell me about?
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Jeffrey,
The most often used math for me is dividing or splitting fractions. The even numbered ones such as half of 8-7/8 are easy, Answer of course would be 4-7/16.
A lot of people think that the odd ones are more difficult to do in your head, but they are not. For example: 7-3/4. If you take the smallest whole number that can be divided by 7, it would be 3. Pretty easy to remember so far. Now take the denominator of the fraction and add it to the numerator. 4+3=7 which will be the new numerator and the new denominator will now be the next smallest fraction. In other words eighths. So, half of 7-3/4 would be 3-7/8. Half of 35-5/8 would be 17-13/16 etc., etc, etc. See, it can all be easily done in your head. Hope you follow me on this, as it's harder to explain than it is to do. Good Luck on your test.
Mad Dog M.
*jeff.. i can't pass this one up...the most important math for the FNG on a work crew is figgerin how to get teh coffee order right..ok.. how many sugars in a 12 oz. regular with how many oz. of cream (RI or NY regular)?how do u divide 12 donuts between 7 carpenters?how much tip do you add for the waitress, if there is a waitress ? if it's a waitress with an attitude?next...if you can work a holiday for double green stamps, can you take the following monday off?next ..how many 8 inch block in a wall 12 ft. high and 30 ft long..?how ,many 12 inch block in the same size wall?
*I follow it. It reminded me of my long ago use of Imperial measure, and it surely explains why I've been happily working in metric for the past twenty years or more! ;-) Sliante!
*Jeffery,Pythagorean theoremKK
*ok jeff.. had to do it..here's one i learned in the army...how to solve for the unknown in a ratio..use it all the time.. it's called the ((((Z))))) method.e.g. 1/2 is to 3/xset them up so you can draw a ZEE and solve for x..x=(2x3)/1 or x = 6, this is used all the time in roof framing..say you have a 5/12 pitch...and you know the run is 9 ft.. solve for the rise...5/12 = x/9 x = (5x9) / 12 x = 3.75 .. set up any known ratio and solve for x...
*Thanks for the math tip Mad Dog!!! It's an awesome brain tissue saving tip!I've never noticed that phenomenom, but will certainly employ it in the future!blue
*Mike, of course, I use the same formula all the time. I learned it in the union apprentice school. It was/is the best thing that they taught me. They called it the ratio and proportion: multiply by the means, and divide by the extremes.5 : 12 :: X : 95 X 9 DIVIDED BY 12 = XWhen I get into a mental pinch, I simply write out that formula longhand. (I don't know what means and extremes mean!) It never fails me.But what I really want to know is the ZEE thing. What significance is ZEE? If it's easier to understand, I have a guy that needs it.blue
*You must know how to calibrate your hammer, unfortunatly this is an increasingly lost art. You will probably have to learn this from a journeyman or an older carpentry textbook.
*Jeff,
View Image © 1999-2000"More than any time in history mankind faces a crossroads. One path leads to despair and utter hopelessness, the other to total extinction. Let us pray that we have the wisdom to choose correctly." Woody Allen
*Joe,At first glance, that means the only number he needs to know is 3.But then I look again, (that's 2), and I see that he needs only to read the tape measure, not carry it, so maybe it's only 2.Looking a third time, (that's 3), I see that he needs only be able to carry a framing square and string line. So maybe that's actualy zero. Now I'm really cornfuzzled. Which is it that he needs to know ? Zero, one, two, or three ? If he goes in there with this one wrong, he could flunk the whole thing, and have to start all over again from day one, (or is that zero ?), running for coffee and donuts every day.One other thing Joe, I've been meaning to tell you, I'm glad that you and others like you are around. To me, you are kinda the carpenter's answer to Isaac Hayes, (You know, the guy what invented gravity.), and Albert Einstien, (was he really as fat as Bill Cosby makes him out to be?)
*blue... here's a crude graphic of the ZEE method..some sergeant taught it and i guess it's school solution..no matter where the X is in the ratio it is always the start of the ZEE so.. it is ALWAYS expressed as..X equals (the next number) X (the next number)divided by the (last number) so set up the ratio or proportion with a pencil and paper... ..start at X and draw a Z.. the first horizontal line of the ZEE is (=) the diagonal of the ZEE is always (X) and the last horizontal line of the ZEE ... is (divided by)even if X is on the bottom.. start at X and draw the ZEE.. no matter which quadrant X is in .. start there and draw the ZEE..if this is less than clear.. send me a fax number and i'll send you a better graphicthis has never failed me , and i'm mathematicaly challengedKermit
*me too
*Sgian,I think you furniture building guys just wanna be different. :-)
*Glad you can use it Blue. It sure beats figurin with a pencil and paper. People will be askin you how you figgured it out so fast!
*Mike & Blue:You have the exact same thing, just different words to describe the process. Same math, same answer. Just pick the easy way for you to remember. I do it a third way ( algebra way?), but it is again the same math and the same answer. Hmm, it seems with the algebra method and the X on the bottom, I have to make an extra step. Thanks for the short cut!Frank
*Nah, Mr. Dog, I'm just an European, British to boot, and we invented all those wacky measurements, but I'm now more familiar with metric lineal measure (at the furniture scale anyway.) I just find it more convenient, but I fully understand those that want to work in Imperial, even though I find all those damn Yards, an' Feet, an' inches, an' fractions a pure pain in the backside to work in nowadays! I'd hate to have to work in Imperial again. Sliante.
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Thank You.
*that pretty cool trick never heard it before can always use it
*WHUT?????
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I'm confused. If the run is 9 feet. And the pitch is five inches every foot. Why isn't the rise approximately 45 inches? Clearly not 3.75 inches.
Rich Beckman
*Rich:If the 9 is feet, then the answer is in feet also. 3.75 feet is 45 inches.Frank
*Oh. Where's that embarrassing moment thread?Rich Beckman
*I musta blinked in Algebra class at the wrond time cuz I obviously missed something important and barely scraped by with C's and D's. However I was Straight A's in geometry. I like this Z method, I am used to doing it my own made-up long way.Then again, thinking about it, I don't ever do it with the whole x factor in there anyhow. For instance a 5/12 pitch and 9' run is automaticly 5x9 to me.Pete
*i no what u mean, pete..i got this theory that there are two kinds of peples..the graphic kinds ((geometry)) and maybe trig...and then there's the algebra guys... joe fusco is a mix..the other thing i noticed is the great piano players are all math whizzes too..anyways , i'm a graphics guy.. with just enuf math to get the job done....so, here's to ZZZZZZZ zorro...
*Mike,Do you think Joe Fusco is probably a great piano player too?
*no... i never asked him... but i wud venture to say that if he took lessons and started playing , that he would be quite good at it...at the mechanics of it... the style.. and feeling .. and the artistry.. who knows?but the hand --- eye---brain---piano connection has a lot to do with the same type of thinking that goes into mathematics...it is some more of that ((right brain / left brain))correlation..how 'bout it joe... do you play the piano?b but hey, whadda i no?
*I don't know about Joe and the piano. But, when I became a programmer, I chanced upon a company that was taking people from all/any backgrounds and retraining them. The only requirement was an aptitude for logic. My company was especially interested in people with musical backgrounds, as they tend to show more aptitude.BTW, the Zee method was taught to me as the X method. Put the two ratios in their proper places (on either side of =). Put a big X where the + is. Mutiply along the branch of the X where you have both terms, divide by the term on the other branch, giving the unknown term. Same method, different names/terminology.Sean
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I am going over all math subs. What are some common carpentry math that you could tell me about?