Confusion between CAD and calculator concerning taper & angle?

Question

I just started working as a draftsman with a company that makes drilling tubes. Today I was presented with a physical part which I must measure the threads and reproduce them on SolidWorks. No biggie, right?

Problem is, one of the guys in the shop put the part on a mill and found the thread taper to be .120 in. / in.. So I went into SolidWorks and drew a 1 inch horizontal line, a .120 inch vertical line, and connected the endpoints to get an angle of 6.84277 degrees. Since this was the first time I've reproduced a thread, I wanted to check my work. Putting the figures into a calculator and doing (TAN(.120))*(180/pi) gives me 6.90868 degrees. What?

I've used 3 different calculators, all giving 6.90868 degrees. This changes the taper to 1.2116701 in. / in.
I've used 3 different CAD programs, all giving 6.84277 degrees.

Should I just pick one? I know there isn't much difference between them, but I want my work to be correct. Would it be safer to take an average of the two?

Answer 1

Old pencil pushing draftsman.

Dont think you need to worry about it too much.

Used to draw threads & gear teeth ( pain in the ...) way before CAD

If it is an illustration get close as you can.

Production drawings often showed a "generic" thread w/ ( fill in the blanks ) notations for dimensions.

As long as the TPI, pitch , diameter , tolerances etc.given are correct you should be good to go.

If they did not give you all the info or did not check it w/ a thread gauge , picking dimensions from a physical piece its a lot to ask.

Best regards

Answer 2

Well, taper to a machinist would usually be the amount the diameter changes over a certain length. You said you drew a vertical line of length 0.120", when you should have drawn a vertical line of length 0.060" to simulate the radius.



Also, just a note, if you're reproducing these threads manually, 0.001" is not a huge difference, and will be hard to hold that tolerance.



That's the way I would interpret it though. Always helps to have the part.

Answer 3

Mormons are Christian. The only requirement for Christianity is a belief in Christ, and Mormons absolutely believe in Christ. She may not share your views, but that doesn't make her any less a Christian. Have you READ the Book of Mormon? If you haven't, how could you know whether or not it is what she claims? Read it first, then judge if you must. Don't just blindly listen to what others tell you, because shouldn't you be trusting your friend first? We have not changed the Bible. We use the King James Version, which is used by most, if not all, branches of Christianity. We haven't even changed a comma. The Bible actually doesn't say that God was never a man. We don't believe that Christ is second to anyone or anything but God. We also know we can't earn our way to heaven, but we don't believe that someone can simply claim to have faith, do whatever they want and still expect salvation, either. Those who have genuinely accepted Christ will be doing their best to live as He has asked, and didn't Christ Himself say that if we love Him, we'll keep His commandments? We believe that Christ expects us to try our hardest to obey Him and then repent when we fail, and in return, He'll make up the difference. Salvation isn't possible without Him, and how does that make Him of lesser importance? No offense, but I'm wondering why you feel the need to prove your friend wrong at all. Judging others isn't really Christian behavior anyway, and can you really consider yourself a decent friend if you won't give her the courtesy of allowing her to worship as she chooses? If she's not hurting anyone, if she's not asking you to convert, is it really your place? Discussion is one thing and can even be positive, but you seem to be trusting to what you've read on the Internet and not trusting your friend to explain her own beliefs.

Answer 4

You have created a right triangle. The side opposite the angle is .120 and the side adjacent to it is 1. Therefore, tan of angle is .120/1 or .120.

Arctan .120 = 6.842773413