Help required to draw 2d drawing

[hemal]

Hello,

I am very beginner in Autocad. Currently I am learning to draw 2d drawings in the Autocad. I am trying to draw as per  image attached. I can't figure out what to do after drawing 130 units line.

Please help me.

[ReMark]

I would draw a line 25 units in length perpendicular to one end of the line that is 130 units.  Next I would draw two circles using the upper end of this perpendicular line.  The first circle would have a diameter of 50; the second would have a diameter of 25.  Do not forget to use your OSnaps (ex. - Endpoint).  Also make sure you are either using Orthomode (F8) or the Polar Tracking feature to keep lines perfectly horizontal or vertical as the case may be.

 

Continue by drawing a line 225 units in length perpendicular to the line that is 130 units using its midpoint as your starting point.  Next draw three circles using the midpoint of the line that is 130 units.  The radii will be 130, 175 and 200.

 

For the sake of clarity I have created a layer called Centerline, assigned it the color Green and the linetype of Center.

 

Edited January 5, 2019 by ReMark

[eldon]

There are different ways of drawing your figure. Some are quicker than others, but as long as you arrive at the correct final result, that is what matters.

Where parts of circles are shown, you do NOT have to draw the arc as shown, but rather draw a circle and trim it down. Your useful commands, among others,  will be Trim, Break, and Fillet. Look at the diagram, and work out the position of lines and centres of circles. See which sides are parallel, where you can use the Offset command. Where you have lines at an angle, I prefer to draw a line vertically, and then use Rotate to put the line where it should be. If the object is symmetrical, then one way to go is to draw one side, and then Mirror it about the centreline.

As an example of differences of drawing, I would Offset the bottom line by 25 to give the centres of the lower circular shapes.

I can see one missing dimension.

[ReMark]

Obviously we do not need the last three circles we drew to be full circles.  We'll need to trim away what isn't required in this exercise.

 

Let's start by drawing a line 225 units long at an angle of 60 degrees.  The starting point for this line will be the centerpoint of our three circles which is also the midpoint of our line that is 130 units.  Start the line command, pick the centerpoint of the three circles, let go of your mouse and at the command line type in @225<60.  Offset this line 25 units to the right.  Use the lines designated in the image below as A and B to trim away the parts of the circles we don't need.  Refer to Step 3 below.

 

Time now to fillet some lines.  Refer to Step 4 below.  Fillet the intersecting lines where the letters 'a' and 'b' appear using a radius of 12.  Fillet the intersecting lines where the letter 'c' appears using a radius of 38.  Refer to Step 5 below.  BTW...I think the 38 radius should have been 37 but we will follow the diagram provided.

 

If you have any questions up to this point please ask.  We'll stop here for now.  BTW...AutoCAD gives us many different ways to achieve a task.  Another member may suggest a different method to follow.  Pick the method that you find the easiest to follow.  My way is not necessarily the best way is all I am saying.  

 

Edited January 5, 2019 by ReMark

[ReMark]

hemal: Have you made any progress on your drawing assignment?

[f700es]

Remark, how did you know that "D" was 38 deg? I see for the top part but to me this is not clear that "D" is the same. Is it implied?

[ReMark]

I believe I said the radius for 'c' was 38 not 'd'.  But now that you mention 'd' I am going to suggest that the OP use a radius of 25.

[f700es]

25 was what I was originally going with.  This took me about 7 minutes to draw. No dims of line weights mind you just to draw out. What did you do it in, 4-5 minutes?
But any way how are we supposed to know what "D" is?

[Bill Tillman]

On 1/5/2019 at 11:48 AM, eldon said:

There are different ways of drawing your figure. Some are quicker than others, but as long as you arrive at the correct final result, that is what matters.

Eldon,

That's one of the great things about AutoCAD, as well as other software. There's always more than one way to accomplish a given task. And I'm always amazed at how other people come up with very ingenious ways of doing things. That's what's great about this Forum.

[ReMark]

Re: Value of 'd'.  This is not the first time we have encountered drawing assignments that have missing or erroneous information.  It makes me wonder about the quality of the instructors who assign such exercises without first checking them for accuracy.

 

As regards the radius of 38.  Since the radius of the interior arc is 12 and the distance between the two lines that are off at an angle is given as 25 I just assume that the radius for the larger exterior arc would have to be 37.  Whether calling for a radius of 38 was an error or intentional we'll never really know.

Edited January 8, 2019 by ReMark

[eldon]

4 hours ago, f700es said:

25 was what I was originally going with.........

 

That was the missing dimension, to which I referred in my first reply.

 

But drawing both 25 and 38 radii, the 25 looks closer to the original diagram.

 

 

[f700es]

25 does look better.

[lrm]

Quote

As regards the radius of 38.  Since the radius of the interior arc is 12 and the distance between the two lines that are off at an angle is given as 25 I just assume that the radius for the larger exterior arc would have to be 37.  Whether calling for a radius of 38 was an error or intentional we'll never really know.

 

No need to assume since it is explicitly dimensioned as R38.  In addition, using a fully scaled image indicates the radius is 38. 

The blue circle in the image below is R38, the magenta circle R37 (the red R25).

I would also assume that the two arcs would be concentric but then I would be wrong!

 

[ReMark]

I have to disagree with you.  The larger radius should be 37 not 38.  The distance between the inner and outer linework remains a constant 25 units as called for in two different locations.  But...I too have made an assumption and that is all four inner (smaller) radii are 12 (12+25=37).  I could be wrong.

 

 

Edited January 8, 2019 by ReMark

[steven-g]

I'd go with 12.5 and 37.5 with a rounding adjustment  . Seeing as the two circles also have a radius of 12.5