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jbgraphic

This problem is just bugging me it seems off.

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jbgraphic

This is a problem from this text book http://www.cengage.com/search/productOverview.do?N=11&Ntk=all%7C%7CP_Isbn13&Ntt=9781111309572#Overview

 

It just seems off to me and I can't get started on the drawing. The slanted face with the two holes is just giving me problems.

 

INSTRUCTIONS

These problems provide you with a dimensioned pictorial view.

Use the given information to select and draw the necessary

multiviews and auxiliary view or views. Do not draw the pictorial view. Set up your drawings with a properly sized

border and title block. Properly complete the information in

the title block. Do not draw the dimension

 

This is what I have so far but it just seems wrong? This is just in the "construction" stage.

P09 - 33.dwg

 

933.jpg

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steven-g

Looking at the image I could only pick out one point that may be an issue, if you take that back edge and line it through, it doesn't line up with the front angled flange face, I would say it lines up to the back of it, which would make more sense anyway. They don't give you a thickness for that flange either, so I would guess at .31 , but you will need a side view to find the true plan thickness. It's difficult to describe (and I know nothing about engineering terms) but hopefully this image will show you what I mean - I could be wrong that's just how I read it.

Example.PNG

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nestly

I believe there are at least 3 dimensions missing to accurately reproduce the part.

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JD Mather

steven-g

Your solution does not show 30° inclined plane.

(or is that an image of the original OP's file - I didn't download it?)

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ReMark

The slanted face appears to have a groove in it which you don't mention. One option would be to draw that as if it were a vertical face and when completed rotate it the required 30 degrees then union it to the remainder of the 3D model.

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steven-g
steven-g

Your solution does not show 30° inclined plane.

(or is that an image of the original OP's file - I didn't download it?)

Yes that image is just to highlight the comment I made, the OP's dwg file shows the top right hand corner as a point, which doesn't allow for the thickness of the upright. I didn't feel that the OP's question when viewed with his drawing warranted further comment on other items at the moment, he is doing OK so far. And was only asking about the basic plan view.

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ReMark

steven-g.JPG

How did you determine the angle of this line?

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JD Mather

This one is challenging.

 

Hint: It's all about the partial auxiliary views True Size and Shape (TSS), (and assumption that that inclined feature is also .31, same as the base feature). Back in a while to show development of the solution.

 

Oops, I think the designer made a mistake in location of the 1.5. The isometric only comes out looking like theirs if I dimension to the tangent with the cylinder rather than to the centerline.

 

Aux Challenge.jpg

Edited by JD Mather

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jbgraphic

Thanks guys.

 

Some good help. I was not correctly "allowing" for the thickness of the slanted part.

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JD Mather
Thanks guys.

 

Some good help. I was not correctly "allowing" for the thickness of the slanted part.

 

Attach your new solution. (Hint: I'll wager that you still aren't "correctly" allowing for the thickness.)

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nestly

IMO, any solution requires assumptions that shouldn't be made.

 

problem.gif

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SEANT

I was prepping a very similar animation. As stated, assumptions are required (I've made similar comments about ambiguous drawing assignments in previous posts), but lets roll with it. A .31 thickness at a vertical angle, though, should be scaled to 0.31/Cos(30 degrees).

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JD Mather

To complete this part - 3 assumptions must be made (but logic can be used).

 

Assumption 1 - that this line is horizontal. (Logic - I also tried with assumption that 1 and 3 symmetrical angles about a horizontal line, but that is a "bigger" assumption and the result isometric did not match given image.)

 

Assumptions.jpg

 

Assumption 2 - the thickness of the inclined feature is .31 same as base feature (logic - duplicate dimension not given). (Hint: the red line is not the same as the thickness of that inclined feature.)

 

Assumption 3 - the 1.5 is to the tangent of the arc. (Logic - changing any of the (reference) dimensions to 1.5 varied too much from the given isometric figure.)

 

I'm going to lunch now. I'll be back in a while to show how to get the length of the red line.

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jbgraphic

So I think I am on the correct track now thanks for the hints.

I did it in Solidworks also to help visualize.

 

 

p09-33.jpg

P09 - 33.jpg

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JD Mather

Looks like you got it.

 

The key is to do an auxiliary view of the side of the inclined feature to get TSS.

 

Auxiliary Solution.jpg

 

Here I have done from 3D model, but easy enough to do in 2D. The location and orientation doesn't really matter as it is all (green/red boundary) is all from known information (if we assume base and inclined feature same thickness.

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JD Mather

Using Parametric dimension and geometry constraints - now have enough information to fully define the base shape.

Geometric Solution.PNG

 

Before you turn in this assignment - you made a typical beginner mistake on the hidden lines from your Counterbored Holes (check the SolidWorks drawing solution).

Hidden Lines.PNG

In fact, there is actually an object line across most of that in the same location. Object lines take precedence over hidden lines.

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steven-g

I told you the OP only needed a hint. I've been out all day. ReMark I drew the plan using the method Nestly showed except I used .358 as the plan thickness of the slope. In this case I would say that the term educated guess is more applicable than assumption, in a lot of cases geometry is so obvious to the person drawing it that they neglect to add dims or angles (I do it a lot) an assumption would be when that top angle needs to be 95° and is the only way to draw the part, but that is just semantics. :D

PS here was my drawing

Example2.PNG

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jbgraphic
Using Parametric dimension and geometry constraints - now have enough information to fully define the base shape.

[ATTACH=CONFIG]44964[/ATTACH]

 

Before you turn in this assignment - you made a typical beginner mistake on the hidden lines from your Counterbored Holes (check the SolidWorks drawing solution).

[ATTACH=CONFIG]44965[/ATTACH]

In fact, there is actually an object line across most of that in the same location. Object lines take precedence over hidden lines.

 

Yeah I got the object line. Was still working through the drawing :).

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nestly

Assumption or guess, there's no way I'd put my name on drawing reproduced from the information provided. As JD pointed out, it is assumed the that 1.5 dimension is supposed to be from the tangent to the corner, even though that's not how it's dimensioned. Is it dimensioned wrong, or did we all make the wrong assumption? To answer that question, yet another guess has to be made.

 

problem1.jpg

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steven-g

Point taken, and I hadn't picked up on that, but I would now say that I drew it wrong the first time round, and would redraw it, using the quadrant of the circle as the rotation point. I would enter a plea of carelessness for missing the dimension clearly coming from the quadrant and assuming it was from the tangent, whilst trying to draw attention to the thickness of the sloping face. :D The main problem in cases like this is the Authors remain silent and the true answer unsolved. Though I would be fairly happy to initial my drawing now (in small letters on the back).

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