
Tinsmith Avenue For those seeking knowledge on past techniques used by yesteryears tinsmiths. The history of Tinsmith goes back in time farther then this place can travel, but for those who want to explore, please share your findings here. 
03142009, 02:04 PM

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Sin,Cosine and Tangent
Could someone give examples of using these three items in a layout project? This is something I need to review. I'm retired but still curious.

03162009, 04:22 PM

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Are you trying to determine how to layout a fitting or distances between elbows used as an offset?
I'm retired also, very good at layouting fittings previous to the plasma cutters, not so good at sitting at a drawing board working out offsets between elbows. Thank god we had a lot people that enjoyed doing that.
I'm old school I have a big three ring binder full of trig functions printed out. The modern way of doing it with a calculator, not as good that way.
To tell the truth I'd have to go back over a lot of things to answer a question using each of those trig functions as you asked it.
If you are working out using elbows as an offset you have to start with the center lines and work from there. Draw them as a triangle and work backwards.

03162009, 07:05 PM

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Distance between elbows used as a offset. Thanks for taking the time to reply.

03172009, 05:12 AM

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See if this makes any sense for you. You just have to work the formulas through.

11102009, 11:58 PM

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Well all I can say these three concepts of trigonometry are fundamental in my opinion to sheet metal layout, however my layout is more math based then most. Since I mainly work on is architectural roofing this is how I would use them. First if I was making a saddle say on a 4/12 pitch and at the roof to wall of the saddle I wanted it to go up the wall 6 inches and I wanted to figure out the dimensions for the side pcs and there mitre, I would take the cosine of a 4/12 or 18.43 degrees and multiply that number by the hypotenuse of the triangle or the 6inch side. Imagine a triangle that is perpendicular to the roof plane. The cosine side would be the vertical side and the sin side would be the horizontal side (parallel to the roof). By multiplying 6 by cosine of 18.43 you should get roughly 5.69 I believe off of memory. for the sin you would do the same steps get the sin of 18.43 then multiply by 6, that should equal 1.89 inches. Now if you are not sure of you answers just use the pythagorean's theorem to double check your answer, 1.89squared + 5.69squared=6squared.
For tangent you could use that on say downspouts, say you want to calculate how much to cut out on the downspout for your bend. say you want to bend it 45degrees totall, so you would split that in half so each side will bend 22.5 degrees. Say the down spout is a 3x3 and now you want to know how much to mark over from the center line, just get the tangent of 22.5 and multiply it by 3 and you get your answer.
Also if you want to layout a cylinder that has been cut out on a roofs pitch by altering a cos function and then graphing it out onto the metal a person doesnt have to physically layout the fitting anymore.

11112009, 11:08 AM

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dam
Quote:
Originally Posted by metalmanmania
Well all I can say these three concepts of trigonometry are fundamental in my opinion to sheet metal layout, however my layout is more math based then most. Since I mainly work on is architectural roofing this is how I would use them. First if I was making a saddle say on a 4/12 pitch and at the roof to wall of the saddle I wanted it to go up the wall 6 inches and I wanted to figure out the dimensions for the side pcs and there mitre, I would take the cosine of a 4/12 or 18.43 degrees and multiply that number by the hypotenuse of the triangle or the 6inch side. Imagine a triangle that is perpendicular to the roof plane. The cosine side would be the vertical side and the sin side would be the horizontal side (parallel to the roof). By multiplying 6 by cosine of 18.43 you should get roughly 5.69 I believe off of memory. for the sin you would do the same steps get the sin of 18.43 then multiply by 6, that should equal 1.89 inches. Now if you are not sure of you answers just use the pythagorean's theorem to double check your answer, 1.89squared + 5.69squared=6squared.
For tangent you could use that on say downspouts, say you want to calculate how much to cut out on the downspout for your bend. say you want to bend it 45degrees totall, so you would split that in half so each side will bend 22.5 degrees. Say the down spout is a 3x3 and now you want to know how much to mark over from the center line, just get the tangent of 22.5 and multiply it by 3 and you get your answer.
Also if you want to layout a cylinder that has been cut out on a roofs pitch by altering a cos function and then graphing it out onto the metal a person doesnt have to physically layout the fitting anymore.

i hate getting the calculator out..if i can draw out a template i will..

11112009, 07:40 PM

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that is so funny that everyone is so diffent, I on the other hand get so tired of drawing some things out that it is just easier to figure it out in the calculator and a lot of time quicker. The caculator does come in handy for some things that you can't layout like a 100' radius or something like that.

11132009, 04:09 PM

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One thing I found in our trade is we usually have a lot of information about the problem. In trig you can find all angles and sides by knowing very little information and using the three functions and the inverse of those three functions {cotangent,secant,cosecant}.
If you concentrate on one function and study it you will be able to solve most problems you come up against. Learn how to pick out the side oposite {the side not touching the angle you want to figure} and the side adjacent {the side touching the angel you want to figure}. these logariyhms are RATIO'S of the sides to each other. Remember that the sum of the three angle's = 180 and a squared + b squared = c squared. c squared  a squared =b squared, c squared b squared = a squared, with one trig function that you master you can do most problems. Once you master one, the rest come easy. I have the three functions on my toolbox so I see them and it helps me to keep them memorized.
One example that a model maker taught me is 1 degree sine x radius x the degree of arc is handy when you need an odd strechout for a part or template. Hope that makes sense.

11132009, 10:26 PM

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Fundamentals to what we do are Law of similar triangles, Pythagorean's theorem, and trigonometry ( mainly sin, cos, tan, and their inverses). Everything in that could be run into can be made from those three things we all learned in high school algebra class.

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