Does the part meet drawing requirements ? 1

[SeasonLee]

Please ref to the drawing attached :
Do you think the part was properly defined on the DRF ? Does the part ( Fig.A and Fig.B ) meet the drawing requirements ?

Thanks for your valuable inputs

SeasonLee

 

[PeterStock]

There is an implied 90 degree angle between the tab and the datum frame established by B and C. This would as you do not show a profile tolerance be controled by a title block default angle tolerance. If you do not have a title block default, there is no control and the part meets the print. I would suggest you control the outside with a profile tolerance.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

http://www.infotechpr.net

 

[pmarc]

There is no relationship between datum reference frame and the tab. Since there are no basic dimensions and no geometrical tolerances specified for a tab, it can be anywhere on a circumference of the part (at any angle to the line connecting datums B and C centers). My opinion is that two parts from figs. A and B both meet the print.

I believe profile of surface attached to the tab contour would work here. If it has reference to datums A, B and C profile tolerance zone will be clearly defined and only one configuration of part geometry will be acceptable.

 

[KENAT]

Initially I leaned toward pmarc's understanding. However, having looked at ASMEY14.5M-1994 section 1.4 i & j as well as at 2.1.1.2 I think Peter may in fact be right.

However, that said, I'm not sure the tab is located linearly from the centerline since I don't think the 3.38 can be basic if no GD&T is used on the tab. Per ASME Y14.5M2.7.3 a separate control is required.

So while the rotation to the 2 holes is probably controlled by the implied 90 assuming there is a tolerance block, it's centering between the 2 holes/perpendicularity to the OD is not controlled.

In fact, I don't think the OD location is toleranced to the 2 holes either so they could be well off from each other.

I've tried to show a combination of this in the linked image.

http://files.engineering.com/downlo...1c6-a8c2-eb6aac98713c&file=DRF-discussion.tif

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[KENAT]

Sorry, that was meant to be 'per Y14.5M-1994 2.7.3'

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[ctopher]

I understand the Right Hand and Left Hand views, but what are Fig.A and Fig.B for? The drawing shows 4 different parts, but only one is fully dimensioned, the other assumed.
You don't show the tolerances, but do the dims 14.26, 7.50, and the floating R3.00 work out with the 15.00 dia dim?

Chris
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[powerhound]

I'm going to go with what pmarc said because there is no indication what the centerline is representing. If it's the center plane derived from the axes of the 2 holes then I believe KENAT would be correct, if it's the center axis of the round part, it would mean something different. The distinction is not made so I think the two parts shown are to print...but probably not as intended.

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[KENAT]

There you go Powerhound, that was the niggling doubt I couldn't put my finger on. As you say, it's not clear if the CL is for the OD or the 2 hole pattern, and as such trying to determine the dimensioning intent is not possible.

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[PeterStock]

The position of the 15 od relative to the holes is set by the drawing, the 3.38 dimension controls the distance of the C hole to the center of the od. The tolerance of that location is not stated however as there is no profile tolerance and the 3.38 is basic. In the vertical direction the 7.50 dimension would be from the holes to the tangent point of the od. This is not clear as the holes are on the od centerline.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

http://www.infotechpr.net

 

[SeasonLee]

It’s a cylinder cam used on door lock, the right hand cam used on RH door and left hand cam used on LH door. When I review the drawing, I did think the part was not properly designed since the most important tab contour was not perfectly defined, that’s why I think the produced part could looks like Fig. or Fig B.

Yes, there is a general title block tolerance on the drawing, but I am with Peter and pmarc, the profile callout added and the relative dimensions change to basic could be the right way.pls take a look at the revised drawing.

Season Lee

 

[KENAT]

If you want to use profile on the tab, then the dimensions for it need to be basic.

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[PeterStock]

Attached is how I would do this part. Also I suggest adding the Csink to both sides with the text on both sides as I have shown. They can be assembled in the wrong place either way, but my way may make for some small savings due to making the parts the same.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services
www.infotechpr.net

 

[pmarc]

Peter got it.
This is almost exactly how I imagined profile of surface usage for this part. I think now there is no place for any misinterpretations and discussions if part can be in that configuration or in the other. There is only one possibility.

Of course we could discuss if countersinks should be somehow positionally toleranced relative to the holes, but that's not the point in this case.

 

[btrueblood]

Kenat,

Can you easily post .jpg images as opposed to .tif images? My new windoze installation can't find a tif image viewer, and I'm too lazy to go reload the freeware viewer I'd had on the last hard drive...

 

[SeasonLee]

Yes, both sides with Cisink, there is R or L stamping on the part for easy identification on the assembly.

Thanks for the sketch, the profile callout is what I prefered and I believe its the right way to defined the tab contour.

SeasonLee

 

[KENAT]

B&W tiffs are smaller file size and clearer than jpegs for my little sketches, so that's why I do it that way.

"Of course we could discuss if countersinks should be somehow positionally toleranced relative to the holes, but that's not the point in this case." why would be discuss that when ASME y14.5 covers it well enough for all but the biggest pedants.

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[KENAT]

Hopefully this gives you the image in your browser btrue.

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[KENAT]

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[btrueblood]

Nope, getting little red boxes now, Kenat. Nevermind, I can just save your works of digital art to my desktop and use the windows viewer to admire them. And, remember not to tip over the computer when stretching my legs, plays heck with the hard drive apparently (who'da thunk?).

 

[KENAT]

I checked with management and Tiff's can't be embedded on this (or apparently most if not all sites/browsers or something like that).

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