Anuncios

The Autodesk Community Forums has a new look. Read more about what's changed on the Community Announcements board.

How do I go about and make this Arc

Anonymous

How do I go about and make this Arc

Anonymous
No aplicable

So I just started learning auto cad in school and im stuck on this one assignment. So I made this entire part but cant figure out how to make that center arc with a radius of 1.25. Any suggestions on how to do this ?

 

pic: http://s614.photobucket.com/user/Ryan_Champigny/media/3ceb1a5c-3d81-43d8-a82a-79bc8fadbd97_zpsigqf7o...

 

thank you.

0 Me gusta
Responder
798 Vistas
7 Respuestas
Respuestas (7)

Kent1Cooper
Consultant
Consultant

FILLET, or Circle with the TTR option and some Trimming.  I do wonder about the Line that meets the upper-right end of that Arc -- maybe you can assume that it's a mirror of the top-edge-ish Line, but it doesn't really give you enough to determine its angle otherwise.  Similarly, I don't think there's enough information to determine the angle of the lower leg.  It looks like a badly-detailed assignment to me.

Kent Cooper, AIA

parkr4st
Advisor
Advisor

I presumed (dangerous to do) that the lower end of the 1.25 arc is located at a point perpendicular to the center of the line between the two centers of the 0.5 arcs off set 1.75 units (0.5 + 1.25).  See the attached. Drew layers Layout first, Layout2 next, and Final last.  Turn off the layout layers to see the Final.

 

Follow Kents ttr advice to add the lines between arcs. 

 

Dave

0 Me gusta

ParishSouthBdx
Collaborator
Collaborator

all good replys.  I thought I would mirror the developed lijne at the topt from R1 TO R2

THEN intersect it with the line developed at the bottom starting from the r1, it would intersect with the mirrored line.. then just fillet the two lines with r1.25.

 

of course that is assuming a lot. poor example of an assignment...........well put.

0 Me gusta

steve216586
Advisor
Advisor

See attached for untrimmed and trimmed version dimensioned.

To find the 1.25 radius you must create construction lines:

1.  mirror the tangent line at the top line, using the center line labelled 4"

2.  draw tangent line from lower circle at 135 degrees

3.  draw circle using TTR between the two using 1.25 as radius

 

There is enough information given to complete this part. Don't listen to the other posters. There is nothing wrong with the excercise.

"No one can make you feel inferior without your consent. "-Eleanor Roosevelt
0 Me gusta

Kent1Cooper
Consultant
Consultant

@steve216586 wrote:

....

To find the 1.25 radius you must create construction lines:

1.  mirror the tangent line at the top line, using the center line labelled 4"

2.  draw tangent line from lower circle at 135 degrees

.... 

There is enough information given to complete this part. Don't listen to the other posters. There is nothing wrong with the excercise.


Your step 1, as well as your 45-degree angle in the drawing and 135 degrees in step 2, are assumptions that are not explicit in the original image.  They look sort of like that, but it's rather distorted.  For example, what you show as 90 degrees in the drawing must be 90 degrees because of the nature of dimensioning, but does not look all that close to 90 degrees in the original -- the longer line is even curved a little -- so how much are other relationships distorted?  Only if those assumptions are correct is there enough information.  Maybe that's enough for purposes of the assignment, but they could have included just a little more information that would have tied it down.

Kent Cooper, AIA
0 Me gusta

steve216586
Advisor
Advisor

My design (attached) shows clearly how every line, arc, and circle are created in a logical means. No assumptions.

 

However, there's no argument when you look at a wrinkled piece of paper and I look at a design. You win because that is simply your outlook on life in general. An argument I can never win.

"No one can make you feel inferior without your consent. "-Eleanor Roosevelt
0 Me gusta

Anonymous
No aplicable

When you look at  steve216586 reply, it becomes easier to work on this exercise. You can rotate the final object at the end to obtain the image on the sheet of paper.

 

You would be better off if you looked at this AutoCAD tutorial site.

 

0 Me gusta