×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Pipe With Hole Features - Hole Alignment in Symmetry
3

Pipe With Hole Features - Hole Alignment in Symmetry

Pipe With Hole Features - Hole Alignment in Symmetry

(OP)
I'm new to GDT, and I can't seem to find the answer to my question.  Even though it's probably right in front of my face.  I know there are a lot of great people here that share good information, so I'm hoping someone here can take pitty on me and help.

I have a length of pipe.  Each end face has a cirular pattern of holes drilled into it.  How do I specify that the patterns at each end of the pipe must be oriented (clocked) such that the axes of symmetry of the holes at the opposite ends are coaxial?

There are no features on the pipe other than it's inherrent cylindric ones, so I can't refer to any particular feature as a datum to specify absolute radial positions for the holes.  All I could do is use the location of one of the holes in the pattern at one end of the pipe and use that as a datum, but is that legal?

I'm new, and I'm stumped.

RE: Pipe With Hole Features - Hole Alignment in Symmetry

I'd scratch a vert. line on each end of the pipe, at the same time, on the same table, with a machinist's square, whatever, to whatever precision you wish.  At 12 o'clock this line might be extended longitudinally onto the O.D. of the pipe for later ref.  If you are end drilling into the pipe itself, you ref. your holes w.r.t. to these vert. lines and the pipe center.  If I were welding flanges to the end of the pipe I wouldn't bother marking the pipe.  I would make two fixtures to hold the ends of the pipe and the flanges in a proper orientation, again on the same fit-up table, and tack weld them in the fixture.  Then move the pipe to a welding positioner for final welding.  Obviously, this has to be done with a details and a few notes of what you want accomplished.

RE: Pipe With Hole Features - Hole Alignment in Symmetry

Make a cross section of thru each hole pattern at either end of the pipe.  You can then specify the angular orientation from a reference.

For example, call SECTION A-A the left hand end of the pipe showing a cross section of the hole pattern.  Call zero degrees vertically upwards and put the angular orientation of each hole relative to that reference position.

Call SECTION B-B the right hand end of the pipe with the cross section through the hole pattern.  Label each hole position relative to that vertically upwards.

On the print through each section draw a leader and say "HOLE ALIGNMENT IMPORTANT".  I typically place a note visible on the print to say "HOLE ORIENTATION AS NOTED".

Done.

Regards,
Cockroach

RE: Pipe With Hole Features - Hole Alignment in Symmetry

(OP)
I apologize for the misplacement of my thread.  I recognized after I posted it that it was not in the appropriate category.  I tried to figure out how to delete it or move it to another category, but I wasn't successful.  Thank you cloa for posting the link.

Thank you Cockroach, and dhengr for your replies.  I thought about referencing a view orientation, but I just wasn't sure if that was legit.  But, now that you explain it, that's exactly what I'll do.

 

RE: Pipe With Hole Features - Hole Alignment in Symmetry

A few notes with the two end views would still be wise, because clockwise at on end is counter clockwise at the other end, particularly critical if the holes are not symmetrical about 12 o'clock.  Maybe define one end as the control end, or my longitudinal mark on the O.D. at 12 o'clock, might help do this.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources