## Turbo Talk => General Discussion => Topic started by: Don Cheke on October 19, 2012, 07:24:46 PM

Title: Draft Angle
Post by: Don Cheke on October 19, 2012, 07:24:46 PM
Does someone know how to calculate taper to get draft angle? Like the taper on an extrude? I divided the angle by two. See attached images and this website: http://www.magafor.net/841/uk.htm What is the formula? Is it something that a person that is not math savvy can understand?
Title: Re: Draft Angle
Post by: Henry Hubich on October 19, 2012, 08:22:04 PM
Taper, as the term is used in your first attached image, is the difference in diameters divided by the length, multiplied by 100. Thus (1.25 - 0.5) / 10 * 100 = 7.5.

Draft angle, as used by TCad, is the arc tangent of the difference in diameters divided by length divided by two. Thus ATN((1.25-0.5)/10/2) = 2.1476Â°

Henry H
Title: Re: Draft Angle
Post by: Don Cheke on October 19, 2012, 08:28:43 PM
Taper, as the term is used in your first attached image, is the difference in diameters divided by the length, multiplied by 100. Thus (1.25 - 0.5) / 10 * 100 = 7.5.

Draft angle, as used by TCad, is the arc tangent of the difference in diameters divided by length divided by two. Thus ATN((1.25-0.5)/10/2) = 2.1476Â°

Henry H

Thank you very much Henry. Somehow I knew it would be you to answer this, our in-house engineer. You are the best!
Title: Re: Draft Angle
Post by: Don Cheke on October 19, 2012, 09:12:57 PM
Taper, as the term is used in your first attached image, is the difference in diameters divided by the length, multiplied by 100. Thus (1.25 - 0.5) / 10 * 100 = 7.5.

Draft angle, as used by TCad, is the arc tangent of the difference in diameters divided by length divided by two. Thus ATN((1.25-0.5)/10/2) = 2.1476Â°

Henry H

Thank you very much Henry. Somehow I knew it would be you to answer this, our in-house engineer. You are the best!

Taper, as the term is used in your first attached image, is the difference in diameters divided by the length, multiplied by 100. Thus (1.25 - 0.5) / 10 * 100 = 7.5.

Draft angle, as used by TCad, is the arc tangent of the difference in diameters divided by length divided by two. Thus ATN((1.25-0.5)/10/2) = 2.1476Â°

Henry H

Henry, can you elaborate on that ATN equation. I must not understand how to use it since I never get your total when I use my calculator?
Title: Re: Draft Angle
Post by: John R on October 20, 2012, 12:37:54 AM
I think Henry's ATN equation goes like what is shown in the picture. His equation returns Radians which are then converted to Degrees, but I could be wrong.
Title: Re: Draft Angle
Post by: Marek on October 20, 2012, 09:03:43 AM
Perhaps this is not strictly a mathematical formula, but the calculation of borehole parameters. If I make the data D = 20, L = 10, d = 10, then we ought to get an slope 1:1, which should give the angle alpha = 45 * and Taper = 100%. And with this formula we obtain Taper = 100% and the angle alpha = 53.13 *.
Marek

PS
Sorry. For height was equal to the radius (slope 1:1), should be of course  D = 20, L = 5, d = 10 and we get the result of the formula: angle = 90 * Taper= 200%
Title: Re: Draft Angle
Post by: GregT on October 20, 2012, 09:58:17 AM
For the mathematically challenged.... just draw the two circles, move one of the circles the required distance, loft and measure.  :o
Title: Re: Draft Angle
Post by: Henry Hubich on October 20, 2012, 10:07:51 AM

Henry, can you elaborate on that ATN equation. I must not understand how to use it since I never get your total when I use my calculator?

On my TI-36X calculator: Subtract 0.5 from 1.25 (answer is 0.75). Divide the result by 10 (answer is 0.075). Divide this by 2 (answer is 0.0375). Press the "TAN-1" key (answer is 2.147585428).

Henry H
Title: Re: Draft Angle
Post by: Don Cheke on October 20, 2012, 10:11:08 AM
Thanks guys. This all helps greatly.

John, I think you are correct. I created a table to a high degree of precision just to see how it might work.

Greg, I had figured out what you had shown, but I wanted to be able to use some equation to help make it quicker.
Title: Re: Draft Angle
Post by: Don Cheke on October 20, 2012, 10:11:57 AM

Henry, can you elaborate on that ATN equation. I must not understand how to use it since I never get your total when I use my calculator?

On my TI-36X calculator: Subtract 0.5 from 1.25 (answer is 0.75). Divide the result by 10 (answer is 0.075). Divide this by 2 (answer is 0.0375). Press the "TAN-1" key (answer is 2.147585428).

Henry H

Thanks Henry. I am not sure why I couldn't get that to work last night.
Title: Re: Draft Angle
Post by: Torfinn on October 20, 2012, 11:28:48 AM
I belive that you forget that you are actualy talkin about a triangle, that mean's you have to use tan ( i belive ),tan = difference between D1 and D2 split on 2 is 0,375, 0,375 divided on L (10)=0,0375
Changing radians to degree vil give 2,14959945096070000000 ho will give 2,15 degree in more normaly numbers
If you make a drawing inside TC with the cirkles and distance, TC will give 2,1500 degree

Torfinn
Title: Re: Draft Angle
Post by: Don Cheke on October 20, 2012, 11:40:38 AM
If you make a drawing inside TC with the cirkles and distance, TC will give 2,1500 degree

Torfinn

This is determined by unit precision. It will be more accurate if precision is set higher.
Title: Re: Draft Angle
Post by: Torfinn on October 20, 2012, 12:27:59 PM
If i change units and angle to 10 decimal, TC gives me 2,1500000000

Also try'd to redraw it after changing this, still TC give 2,1500000000

Torfinn
Title: Re: Draft Angle
Post by: GregT on October 20, 2012, 01:07:13 PM
When drawn in TC... I get 2.1475854000Â° at 10 decimal places
Title: Re: Draft Angle
Post by: Kenneth Martin on October 20, 2012, 01:12:37 PM
Taper, as the term is used in your first attached image, is the difference in diameters divided by the length, multiplied by 100. Thus (1.25 - 0.5) / 10 * 100 = 7.5.

Draft angle, as used by TCad, is the arc tangent of the difference in diameters divided by length divided by two. Thus ATN((1.25-0.5)/10/2) = 2.1476Â°

Henry H

Yeah Don, what would we do without him here at the forum?
Thank you very much Henry. Somehow I knew it would be you to answer this, our in-house engineer. You are the best!
Title: Re: Draft Angle
Post by: Torfinn on October 20, 2012, 02:11:41 PM
When drawn in TC... I get 2.1475854000Â° at 10 decimal places

Is there then some other place for set this rather then space units and angle inside the option menu ??

Attach how it show inside my TC 19.1  43.2   Pro Plat

Torfinn
Title: Re: Draft Angle
Post by: GregT on October 20, 2012, 02:53:22 PM
Under your dimension properties... try setting your Round off and Precision to the following... and see if that helps.
Title: Re: Draft Angle
Post by: John R on October 20, 2012, 03:10:12 PM
re: Is there then some other place for set this rather then space units and angle inside the option menu ??

I've found that changing settings for the Standard style in Dimension Styles (Style Manager palette) to be helpful. You can increase the precision there to something like 15 or 17. See the bottom of the Dimension Styles (http://www3.turbocadcommunity.com/tiki-index.php?page=Dimension+Styles) page in the Wiki.
Title: Re: Draft Angle
Post by: Torfinn on October 20, 2012, 04:57:32 PM
Thanks John R

There it was :), under style manager i have " Round of for primary " set to 0,01, changing to 0,0000000001 and the changes i make inside "space units " have effect for the 10 decimals

Torfinn
Title: Re: Draft Angle
Post by: GregT on October 21, 2012, 05:37:59 AM
Things to note:

1. Changing settings in the Style Manager effects both existing dimensions in the drawing (except those that were overridden), and those placed after any changes are made.

2. Changing the Dimension Properties settings by right clicking on the tool only effects dimensions placed after the change.... existing dimension in the drawing remain as they are.
Title: Re: Draft Angle
Post by: Torfinn on October 21, 2012, 07:57:49 AM
And there my english skill's come in  :) GregT, i didnt understand the syntax of "round of" inside the property, i try'd to change it to 0, 1 and 10 but nothing happens
When i look inside the wiki, then i understand how i should write it.

Torfinn