doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com making heavy barrels lighter

R'Man;
Thanks for the compliment. My math skills are nowhere near yours though. During my working career as a machinist outside of just plain arithmetic I used more trig than anything. Trig of course doesn't come into play here.
I had just assumed that taking that median diameter times half the metal removed from the diameter differences would be a close approximation. had not realized it would in fact be exact.

I appreciate all the comments here and deeply appreciate Rocketman and 2-Piper's math skills. My worst subject. A passing grade for yours truly was an act of charity by my high school math teacher!

My reports think I'm from the stone age calculating on my trusty HP-41CX. (formerly C then CV)...as for area of circle formula I prefer to cut to the chase and go with pi r2 the only issues I have is dealing with inches as I work in decimal feet. 276' diameter tanks are a lot of inches

Ken;
I can't say for certain but I would assume when working with a tank that size you would not be dealing in cubic inches, but cubic feet or even cubic yards. the formula works identically for any unit of measurement as long as you keep all components on the same scale. Thus if you use feet for the diameter you have to also use feet for the length/height of the tank.
As to Pi xD�/4 versus Pi x R� they are of course the exact same formula. As R = D/2 then (D/2)� D�/4. When I am using this area formula I will normally be working with a diameter rather than a radius so I just Sq the D & divide by 4 rather than divide D by 2 & sq the result. Multiply by Pi either way. Exact same number of keystrokes on my faithful Casio Calculator.
I have absolutely not the Foggiest idea where that &#960 came from. I held down the alternate key & typed 227 & the Pi symbol came up. When I post every time it has thrown in that &#960 instead. I have gone back & edited & used the letters Pi instead of the symbol. The listing I have for these says to hold Alt & the Windows symbol but for ages I have only held the alt key & it has always worked. As a test I am going to try Alt & Win then 227 & see if it transports OK.
Test = π
Obviously that's not the problem, When I typed it in it came up with the Pi symbol plain as Day but when I send it comes out this GobbledeeGobble.

Miller,

If I were using your Casio I would most certainly end up with an incorrect answer. For better than forty years I've used nothing be HP calculators that utilize RPN (Reverse Polish Notation) logic. (X enter y +) to use a normal calculator like yours (x+y=)
I struggle. All good!!

It is certainly fascinating to see the turmoil a grade school level calculation can cause.

I suspect the root cause is that this is the "pie are round" contingent.

I hope none of you work for NASA

Well I never worked directly for NASA but I built or helped build a pile of test models that ended up in Nasa wind tunnels in my career. I once on this board made the statement that areas of bores were proportional to the Square of their diameters. Some very Brilliant Mathematician posted back they were not proportional to their diameters but their radius. Duh , since the radius is diameter/2 if they are proportional to one they are proportional to the other.
Sometimes you just have to get down & Basic to make people understand that you can work from the diameter same as the radius if you use the proper figures.

Ken;
Never did like those RPN calculators. I started also over 4o years ago (was one of the first machinists in our shop to have a calculator) with a "Normal" calculator & learned to use it. I got on the Casio's due to their trig functions. I worked with a lot of angles which were often given in degrees, minutes & seconds. The Casio was to the best of my knowledge the first reasonably priced calculator which allowed you to take a trig function directly form an angle entered as � ' " . Most others of the early times if I wanted to take the Sine say of 15� 30' I would enter 15.30 but would then have to convert to 15.5 before taking the function. The Casio was simply much easier to work with & once I got to using them I just stayed with them even after other makers upgraded to the same method of doing the trig. .

Actually what I should have said was that I'm glad none of you worked for me.

Bottom line was a poster here wanted to know how much weight he could remove by enlarging the bore of his Shotgun. I figured it for him. Any problem with that.??
I do "VERY HIGHLY" suspect you are not near as Glad I never worked for you as "I AM".

Miller,thank you very much for providing the figure of 4.7ozs per .010" of steel? It is a valuable piece of knowledge to use when evaluating vintage guns.