Thread: Sine bar setting taper attachment

taper is .5/12, thats .0416r/1 so...SOHCAHTOA, using oposite and adjacent sides, we need to use Tan(-1), Tan(-1) of .0416r is 2.385943992deg. Thats to as many places as my calc has.
I always like to do the math myself rather than trust a spreadsheet or program.
Ew

Ok I am not sure what you are saying it's to unexplained. However it seems your calculation is different to mine.
Mine is 1.5 - .5 = 1 / 12 = .08333r then I press 2nd & Tan-1 on my calculator = 4.76364169 / 2 = 2.3818208 half angle .
This is exactly what the spread sheet shows also.
So am I doing the wrong calculation ?
I need to understand your calculation better otherwise I will not be able to change the spread sheet .
I would appreciate some breaking down and explanation of how you did your calc.

Ok, you cannot work out the half angle by calculating the whole triangle like that and dividing the result by 2. Sin/Cos/Tan only work for right angle triangles, and the full triangle is not a right angle triangle.

You need to split the taper in half first, so if it is 1/12 overall, then one side of the taper is .5/12, or .0416r.

The way i remember which function to use is SOHCAHTOA. Where S is sin, C is cos, T is tan, O is the opposite side, H is the hypotenuse and A is the adjacent side.

So we need to used Tan (we are using the opposite and adjacent sides) -1(as we are working out an angle from the sides ratio) Tan-1 .0416r is 2.38....

My dodgy triangle solver app on my phone gives me 2.386deg. There is a calculator here Triangle Calculator which is pretty handy, just be sure to add as many decimal places as you want the answer in, even if they are just 0's

Hope that helps (and i hope i'm right)

Ew

Thanks that helped a lot what I did was divide the initial output by two and apply Arctan to that product and it gives the exact same values as yours and the other programs I have also. Also checked it against another online source and it's bang on now. Thanks mate that's another step closer.
I am fairly pleased It's my first go at an Excel spread sheet and my math stinks and I have two useful calculators now , their not fancy looking but they work now after a bit of tutoring.

It might be time for me to get a new calculator retromilling. I just worked it out and came up with 2.385944030388813 degrees as being half the included angle of your taper.
I've learnt also that Ewan is rarely wrong.
On the phone on holidays so please insert the smilies.

Phil

Originally Posted by Steamwhisperer

It might be time for me to get a new calculator retromilling. I just worked it out and came up with 2.385944030388813 degrees as being half the included angle of your taper.
I've learnt also that Ewan is rarely wrong.
On the phone on holidays so please insert the smilies.

Phil

I am getting that value also now because Ueee pointed out that my initial math structure was wrong . Now I'm fine and I have adjusted the spreadsheet math and it concurs with the calculator and my old DOS programs and internet based calculators so I'm 100% sure now it's right .
The good thing about a spread sheet compared to the old DOS program is you can quickly replace values and get results without having to open and close the program each time. A side benefit has been that during this exercise to build spread sheets I was forced to also work out how to do it manually on a scientific calculator . Something I could not do two days ago . My old DOS programs have served me well but they will not migrate to windows 8 without running XP in a virtual machine and that makes the whole process slow and annoying.
Now that I have succeeded with Taper calc and Sine bar stack height on spread sheet I will try to convert some others later on .
Thanks for the input everyone . Now back to scratching my head over this taper attachment concept .
.

Originally Posted by Steamwhisperer

It might be time for me to get a new calculator retromilling. I just worked it out and came up with 2.385944030388813 degrees as being half the included angle of your taper.
I've learnt also that Ewan is rarely wrong.
On the phone on holidays so please insert the smilies.

Phil

Is a ride on the National Railways Museum trains in order Phil?

Dean

Originally Posted by Oldneweng

Is a ride on the National Railways Museum trains in order Phil?

Dean

Done, and I only took 8000 pics.

Phil

Something like this?

Gene