Penn Foster Sheet Metal drawing project

[SLW210]

On 11/15/2019 at 8:50 PM, gogrey34 said:

If I used the equation for BD that they gave, I get a negative number. -0.2483?

I found a different equation after some google searching that has it as

BD=2*(tan(A/2)*(R+T)-BA

I got 0.2867 for the BA and 0.4133 for BD using the equation above. 
I didn’t see the BD equation in any of my searching. 

 

10 hours ago, banyameen said:

the bend deduction is 0.0633 inches is not right and i founded is .413

 

Yes, that has already been mentioned.

[oddssatisfy]

On 11/13/2019 at 9:33 PM, gogrey34 said:

Hi CADTutor folks! It appears PF has changed the drawing project in the HVAC section after searching for some topics. The project is to draw a multiview drawing and flat pattern for a bracket made out of sheet metal. I'm getting tripped up on the flat pattern when it comes to calculating the bend deduction with the formula they give (pg 12 in attached pdf). Right after the formulas for bend allowance and deduction, they say "you should find that the bend deduction is 0.0633" and the bend allowance is 0.2867". I had no issue getting the same bend allowance number, but I'm not getting what they said for the bend deduction. Pg 6 lists K-factor(K)=0.33, bend radius(R)=0.1", thickness(T)=0.25", and says all bends will be 90°(A).

 

I've found a considerable amount of typos in the course up to this point, so it really wouldn't surprise me if there was a typo in these instructions as well. I have an email submitted to PF asking for clarification, but I figured I might get a quicker answer on here.  

 

So for those of you who enjoy a good math problem, can you get the bend deduction they have of 0.0633? I even busted out my trusty old TI-86 graphing calculator to figure it out. I've been out of school for way longer than I care to admit to myself, so it's definitely possible that my advanced math skills are bit rusty Sheet Metal Parts. Any insight would be appreciated!

 

Thanks!

Amy

 

 

7. HVAC and Electrical Schematic Drafting - Lesson 2.pdf 405.15 kB · 42 downloads

I am trying to work on my Structural Drafting Project for AutoCAD. I am very visual and i need to draft plate 1 the foundation plan. It's been awhile since I've been on the forum, and I cannot seem to find the thread that talked about this project. If someone could please direct  me in the right direction. I would be so grateful. I am trying to get it started and am having a bit of difficulty understanding how it is supposed to look.

Edited January 12 by oddssatisfy

[ReMark]

I may be of some assistance.  You posted in the correct subforum (Student Project Questions) but you posted under a thread about the P-F Sheet Metal Project.  Stay in this subforum and use the Search function in the upper right-hand corner.  Search on the word STRUCTURAL then view the results.  You should find what you are looking for.

[xiaoqiqi]

On 1/12/2025 at 7:31 AM, oddssatisfy said:

我正在尝试用AutoCAD进行结构绘图项目。我非常注重视觉，我需要绘制基础平面图1。我已经很久没上论坛了，但似乎找不到讨论这个项目的帖子。如果有人能指点我一下，我将不胜感激。我正在尝试开始这个项目，但不太明白它应该是什么样子。

Hi Amy,

You're absolutely right — the values PF provided seem inconsistent with standard bend deduction calculations, especially if you're following standard K-factor rules. If the K-factor is 0.33, with a bend radius of 0.1 and a material thickness of 0.25, then using the usual bend deduction formula:

ini

BD = 2 × (T + R) × (π/4 - K)

...doesn’t quite give you 0.0633. So unless they’re using a software-specific table or a tooling preset, the number might be off.

We recently dealt with a similar problem in a CNC + sheet metal prototyping project, where our team couldn’t match the deduction until we worked directly with a fab partner who had real-world calibration data. If you want a fast answer, you might want to reach out to someone who regularly handles CNC bending + fabrication.

We once got great help from this team:
They specialize in precision sheet metal and can usually give quick advice based on their bend tables.

Hope this helps! Let us know what you find out.

Best,
J

Edited May 16 by SLW210
Deleted Link!

[ReMark]

Penn-Foster is not noted for the accuracy of their project instructions.  They are teaching an AutoCAD course, not a sheet metal fabrication course.

Edited May 23 by ReMark

[Autoconfused]

On 11/15/2019 at 1:34 PM, ReMark said:

I have two other points of contention I'd like to address. 

 

The first is P-F instructs the student to use the ROTATE3D command to rotate the 3D model.  The axis and the degree of rotation are specified as X axis, –90 degrees / Y axis, 45 degrees  / X axis, –35.2466 degrees.  Shouldn't the three axis be X, Y and Z? 

 

The second is the student is instructed to modify the 3D model by deleting lines, substitute hidden lines for continuous lines, extend some lines and redraw a hole that penetrates the bracket using an arc instead of a circle because it's view is partially blocked by one leg of the bracket.  Unless one were to explode the 3D model this would be impossible.  To create a 3D model then explode it for the purpose of constructing a perspective view of the bracket, in my opinion, would be a huge waste of time.

 

I have not completed the reading of the full PDF.

I'm currently trying to do this 3d rotation, either way seems to come up with a 3d bracket that is definitely not positioned for an ISO view. What am I doing wrong here? I've mostly been confused throughout all of Penn Fosters program with missing information and typos.

[ReMark]

Open View Manager.  Select Preset Views from the dropdown menu.  Then select one of the four 3D isometric views:  SW, SE, NE or NW.  Done.

[Autoconfused]

2 minutes ago, ReMark said:

Open View Manager.  Select Preset Views from the dropdown menu.  Then select one of the four 3D isometric views:  SW, SE, NE or NW.  Done.

The fact that this is an option and he has me doing it with 3 different rotations makes me wonder how qualified the instructor is and if anything is audited. Thank you SO much! I've learned more scrolling through here than through the actual course.

[Autoconfused]

7 hours ago, Autoconfused said:

The fact that this is an option and he has me doing it with 3 different rotations makes me wonder how qualified the instructor is and if anything is audited. Thank you SO much! I've learned more scrolling through here than through the actual course.

But to put my foot in my own mouth. How do I rotate the object correctly instead of my view?

[ReMark]

What do you mean by "rotate the object correctly"?  You could use the 3D ROTATE command that allows the user to rotate objects around a defined axis in 3D space.  Users can specify an axis by selecting two points, using an existing as an axis, or using the X, Y, and Z axes.  You can also specify the angle of rotation.  Try all methods and choose the one that you feel works best for you.  As to your original question (four posts above this one) regarding the P-F instructions the angles are X, Y and Z not X, Y, and X.   

[Autoconfused]

I tried it with x,y,x and x,y,z. I can't seem to get either to rotate to the correct position. I'm never sure if im doing it wrong or if the instructions are incorrect somehow. So I cant get the object to rotate to the correct orientation. I also can't get a good hold of which way its going to turn when I pick an axis and enter a value, it never rotates the way im trying to get it to, any tips on that would be appreciated as well.

 

[ReMark]

It is important to note the direction of your UCS icon for starters.