# Thread: pi 3.14...

1. Originally Posted by serpicojr
So how do you do trigonometry if not with trigonometric functions?

You mean triangle math and circle math? I do it all the time. I rarely use sin cosine tangent values, in formulas though. I admit that I use a cadd program that uses them all the time. However without a cadd program I would not use them.

Over the years while using the machinists handbook. I came across a lot of great formulas. But to be honest if I have to use sine cosine or tangent tables without remembering the tables, it is dangerous to use them because you are assuming that they are correct or that you entered it correctly.

You are working with numbers that are six or ten places out, to try and hold accuracy. By the time I put all these numbers into a calculator, right them down or play store and recall a few times. I can assure you I am not doing math.

Math is done and you are sure. Mathematicians practice, a lot and I never even attempt to beat them for coming up with ideas or solving problems because I know anyone can come up with a great way to solve a problem. Mathematicians usually come up with great ones.

But usually the mathematicians when they get to the job or site, stall out. Because they realize that the perfect mathematical world does not exist.

Often mathematicians cannot believe how hard it is to measure one piece of metal accurately. So all the calculations are usually better performed by older tried and true methods.

I drew this rail in about five minutes using cadd. I just installed it today. Cadd is an awesome way to do it.

If I had to lay it out on a table it would take about a half hour to do. I would have more work taking the pipe in and out of the bender as well.

However I could cut down laying it out on a table to about five minutes if I created some little gadgets to show the ratio of angle to length of pipe before it was bent. It would be rather easy to do. But you would lose the ease of designing and redesigning on the computer. You would be much more tired laying it out on the table many times then on the computer.

I have noticed that with the cadd drawings statistically my rails are 100 percent to the drawings, accurate.

I once made a rail that I forgot to draw in a step while drawing it up. It came out one step short of the first step. It was funny though that this never happened to me with the old system. But still all in all, the drawings make it happen faster, more accurately. We just need to implement computer design entry to speed it up and make it more accurate.

Without cadd I was running probably in the high nineties for accuracy.

Sincerely,

William McCormick

2. Just out of curiosity, but do you really think the programmers who wrote that program could have done so if pi was some arbitrary variable? Or without all of the math you've been agruing against? As a professional programmer, I can say with certainty that they could not (and yes, I've written programs similar to this).

3. Originally Posted by MagiMaster
Just out of curiosity, but do you really think the programmers who wrote that program could have done so if pi was some arbitrary variable? Or without all of the math you've been agruing against? As a professional programmer, I can say with certainty that they could not (and yes, I've written programs similar to this).
For what we do with it, it is more then accurate enough.

But if you are setting standards for understanding an ARC, you need to measure it somewhere in the real world.

You cannot sit somewhere and hope that it is what you contemplate it is. Look at all that have contemplated it in the past. If the contemplators were correct then the world is indeed plausibly flat.

I am saying that right now given our equipment, I trust cadd to make railings and other measurements, even over long distance. Where error is multiplied.

But if I were going to be making a lot of precision stuff. I would use x,y coordinates, and rotary table. To position the points. And use that system to relocate them again and again.

In other words to get to an exact point diagonally across the part. I would not want to calculate A^2+B^2+C^2 to get there. Swing the part 45 degrees and then move the table the distance the computer output.

I would let the computer do that but then get the x,y coordinate for that point and then move by x,y movement to that point. Even if the hole is off a bit at least I know where it is.

I do trust the computer more then most that use them. These elbows were cut using a computer driven plasma table. I called in the degrees I need the elbows plasma cut to. I then welded the individual gores that make up the elbow, together and put one elbow onto each section of pipe at the shop. Then at the site I connected the pieces together.

I was so confident in this method. That for fun halfway through welding one section we just moved it into place so we could pat ourselves on the back. It was perfect.

Welded the second one together, butt joint at each joint. It came out perfectly. This is part of an underground fresh air system in Manhattan.

http://www.Rockwelder.com/Welding/St...d/sspipegr.jpg
http://www.Rockwelder.com/Welding/St...d/sspipetv.jpg

This is a link to how they calculate the gores.

http://www.rockwelder.com/Flash/elbo...elbowcuts.html

Sincerely,

William McCormick

4. You guys may like this: I've recited pi in 400 decimals.

http://www.youtube.com/watch?v=yf2Cn...?topic=13734.0

I know it's far from a world record, though.

Page 2 of 2 First 12
 Bookmarks
##### Bookmarks
 Posting Permissions
 You may not post new threads You may not post replies You may not post attachments You may not edit your posts   BB code is On Smilies are On [IMG] code is On [VIDEO] code is On HTML code is Off Trackbacks are Off Pingbacks are Off Refbacks are On Terms of Use Agreement