35 Replies Latest reply on Dec 15, 2017 5:19 PM by Matt Peneguy

# How do I find the dimension of this shape?

Hello, so I am new to solidworks and engineering in general. My teacher has given me the task to create the part below in solidworks however I do not know the width of the highlighted area. The length is 48mm but how do I find the width? thank you

I'm guessing it's 24mm because the it's 12mm from the hole to the edge so is it safe to assume it's 12mm the other way too so 12+12==24mm width?

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Edit: Yes, because the arc is tangent to the edge at the left.

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Thank you for confirming!!

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Corey, if you model it EXACTLY as it is dimensioned you won't need that particular value.  That is actually part of the exercise, to demonstrate that very thing.

A properly dimensioned drawing has all the information necessary to define the part.  This one does.  All you need to do is model it as the drawing shows and use those exact dimensions.  The only other thing you have to do is to constrain lines with their appropriate geometric constraints, such as tangent, vertical, horizontal, etc.

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Is it 24?

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Matt Peneguy wrote:

Is it 24?

I just confirmed with my Calculator.

That is correct.

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Not only confirmed, but "Scientifically" confirmed...

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Wait jus a minute here...

the radii is 12. That makes the diameter 24.

Add the 24 to the linear 12 dimension and you get 36.

My guess is 36

However, when I held my 12" ruler up to my monitor I can proudly confirm that the distance is .55 inches.

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MS Paint says its 0.84"

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I get 7/16"

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Ruler needs to be flat against the screen

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That edge was against the screen, I tilted the bottom edge of the ruler up. I'll get my calipers out if I have to!

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J. Mather wrote:

Matt Peneguy wrote:

Is it 24?

I just confirmed with my Calculator.

That is correct.

You, sir, have a great Friday snark going!!  I'm guessing you are feeling some great release at the semester being over.

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Grades are in and so far nobody has complained....

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J. Mather wrote:

Grades are in and so far nobody has complained....

They're probably just sharpening their knives!

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J. Mather

I don't know how you do it.  I remember as I was entering the classroom asking one of my math Professors why he seemed upset.  He explained that he had just given test results back and one of the students had argued with him that his answer was correct.  It was a compounded interest problem and the result the student had answered was less than the initial amount.  The student was arguing that he had used the equation and therefore his answer was valid, or something like that.  It was at that point, even though I was in college, I realized Professors have to deal with some ridiculousness...  You sir, have a good Christmas break!  I know you have earned it!

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It is something like using a sledgehammer to crack a nut.

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You mean like the Sledge-o-matic?

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The drawing is actually over-dimensioned. Is has the 88 dim, plus all the dims that make up the 88 (12 + 6 + 30 + 6 + 34). It would have been a more interesting challenge to leave the 12 dim off the drawing.

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Scott Stuart wrote:

The drawing is actually over-dimensioned. Is has the 88 dim, plus all the dims that make up the 88 (12 + 6 + 30 + 6 + 34). It would have been a more interesting challenge to leave the 12 dim off the drawing.

You are correct!

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Lol, I was just about to post that! I enjoyed doing these little puzzles back in the school daze...

And, I believe part of the sketch is also under-defined. Certain relations are typically assumed, but...

Help me out here people- for the life of me I can't confirm the dimension illustrated below.

Two questions:

1. What is this width? (see image)
2. Should it be assumed that the top horizontal line is coincident with the center of the top left hole/radius?

So, is it defined or not? And how so, by the assumption?

I personally wouldn't 'release for production' based on that...I would want a confirmation.

Am I still missing something?

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If you make tangent relations at the locations shown, it should lock down the geometry (same with the bottom):

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They are tangent as shown.

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If all those arcs are tangent where they intersect all of those straight lines, it should be fully defined.

Can you post that part?

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I also assumed tangent here, though hard to confirm with the wrinkled worksheet pic..

I'll try to post my sketch...

Haven't done that before

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I respectfully disagree. If you have sketched it up, I would assume that SoiledWorks added an assumed coincident to your sketch automatically....

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Hey, you may be right, that's why I asked for the part file.  It "looked" like it would be fully defined with those tangencies, but you and Rick Becker may be right. There may still be something missing...Just tryin' to help.

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And appreciated!

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I see my mistake, I assumed the two points below were coincident, and I think you pointed that out:

If those two points are not coincident, you definitely need another dimension.

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SLDPRT is attached

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James Harvey wrote:

...

1. What is this width? (see image)
2. Should it be assumed that the top horizontal line is coincident with the center of the top left hole/radius?...

1. The width is the one missing dimension.

2. No. That level of assumption jumps the shark.

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And it doesn't anyway:

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That's what I'd do and note the assumption on the print. Remember, this is a class assignment.

James Harvey wrote:

Should it be assumed that the top horizontal line is coincident with the center of the top left hole/radius?

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For a classroom, me too. Actually, I'd call my instructor out on it!

But if you work in manufacturing I hope you have deep pockets!

Assumptions produce \$crap metal!!

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You know..... (and maybe J. Mather can confirm this):

Sometimes I wonder if these types of drawings are purposefully poorly dimensioned to see if the student asks the right questions.

In this example, the threaded holes are poorly dimensioned (no pitch called out [but you could potentially assume the standard coarse pitch...still...) and the width as someone else pointed out.

I mean....did the teacher try this him/herself?  And then take out the missing dimension to see if they asked?  Or was it just laziness?

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Dan,

I doubt it was left out intentionally.  If the class is to teach SolidWorks, that would be counter-productive.  I would guess it was an error.  My eye didn't catch it because I made an incorrect assumption.  You and Rick just have a better eye than I do.