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Thread: Thru holes in a hollow cylinder (pipe, tube, or hollow shaft)

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    Thru holes in a hollow cylinder (pipe, tube, or hollow shaft)

    I have a drawing showing (2) .500 holes on the side of 3-1/2" NPS pipe. The hole note reads "2X 0.50 THRU". The drawing shows (2) holes spaced 1.35" apart. My question is, do the holes go through the pipe wall only, or totally through the pipe, creating 4 holes. There are no other views with hidden lines to indicate what the designers intentions might be. The drawing is governed by ASME Y14.5M-1994.

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    Welcome to the forum.

    Hmmm, generally that would mean through one material thickness, but, there is no way of knowing the designer's intention and the competency of the draftsman (generic term OK). Without an assembly or mating parts(s) to make an educated guess, it would be unwise to assume anything.

    Sooo, that would be a question for the client.

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    I was afraid that would be the answer. The customer is a government contractor, so all questions create alot of red tape, not to mention time. I do not have a ASME Y14.5M 1994 handbook, does the handbook define the above question as only through the wall, since the drafter called out 2X and not 4X?

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    Quote Originally Posted by jarey1968 View Post
    I do not have a ASME Y14.5M 1994 handbook, does the handbook define the above question as only through the wall, since the drafter called out 2X and not 4X?
    I can't help with the handbook, but as I said, there is no way of guessing the draftsman's intentions, competence or level of understanding of the Dimensioning Code.

    Is there an Elevation view that shows the center-line passing through both sides?

    In my one brief (9-months) foray into working on Government projects, I can assure you that the time wasted asking the question now will be much shorter than fixing the problem if you guess it wrong.

    I was amazed at the level of redundancy, incompetence, laziness, lack of responsibility and poor technical knowledge of the Engineering staff I had to work with in a Federal department, I vowed "never again."

    My final word here is to quote something generally printed on every drawing sheet that I am sure we have all fallen foul of at least once in our Engineering lives, "If in doubt ask!"

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    I am in agreement with Dave. Think about it - the only reason you are asking for the standards is to give yourself cover if you don't make it the way they want. We all know the standards cannot tell you what the designer's intent was. Only the designer can do that. And you have no guarantee at all that the designer followed the standard. If you do get it "wrong", the defense that you followed some standard might help a little, but it won't solve the problem, and you will still be blamed. They will NEVER blame themselves after all. As the man said, "If in doubt, ask."

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    The latest edition of Y14.5 mentions this only briefly. It's in paragraph 1.8.10: "Where it is not clear that a hole goes through, the notation THRU follows a dimension. Where multiple features are involved, additional clarification may be required." So it sounds like your original question is legit -- the designer really should have clarified things further.

    JPB

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    I have a similar problem, but I'm the one creating the drawings. I have a round tube and one hole that goes thru both sides of the tube and three holes that go thru on wall thickness only. What is the best way to callout the holes so the person or company drilling the holes knows what I need. I was thinking of noting "THRU" on the hole that goes thru both sides, and on the other ones noting the thickness of the wall which is .25. Is there a standard that I can use? Thank you.
    By the way should I start a new thread for this question?
    Last edited by DiegoMunoz; 10-24-2011 at 06:11 PM.

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    Technical Fellow jboggs's Avatar
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    If there is any chance of misunderstanding I usually just note something like "THIS SIDE ONLY", or "FAR SIDE ONLY".

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