Bolt hole orientation
Bolt hole orientation
(OP)
HIII Guys,
All Flange Bolt Holes Straddle the Center lines that is for a vertical flange face (the flange face in the vertical and the line is horizontal) the bolt holes want to be orientated to straddle the vertical and horizontal center lines and also for the horizontal one the bolt holes want to be orientated to straddle the Plant North center lines.
What is requirement of straddle the holes from center line?
If we found one tank man way with bolt hole is on exact center line,what action will take?
All Flange Bolt Holes Straddle the Center lines that is for a vertical flange face (the flange face in the vertical and the line is horizontal) the bolt holes want to be orientated to straddle the vertical and horizontal center lines and also for the horizontal one the bolt holes want to be orientated to straddle the Plant North center lines.
What is requirement of straddle the holes from center line?
If we found one tank man way with bolt hole is on exact center line,what action will take?





RE: Bolt hole orientation
For items such as manways, there is only the mating flanged plate, therefore in practice it might just look a bit strange, but otherwise is technically acceptable.
See what the specification or data sheet said and if it says staddle the centerline then ask them to cut it off and rotate.
Depends on whether you can handle the schedule delay and possible claim from the vendor.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Bolt hole orientation
Sometimes its possible to do all the right things and still get bad results
RE: Bolt hole orientation
As exhibited in the attached photograph of an exposed portion of the Versailles pipeline, presumably designed by Mariotte more than 350 years ago (and that I understand is mostly still in service after three and a half centuries), it appears that the original installation was with the flanged/bolted joints installed with the bolt holes/locations “straddle the vertical centerline” (or “two-holed”). While I guess I shouldn't attempt now to explain Mariotte's thinking, I do believe maintaining such convention in design, manufacture and installation of at least bolted flanged piping probably facilitates constructability (e.g. with spirit levels etc. laid across bolt holes), provides a frame of reference for adjoining fitting and other specials directions (when drilling is purposefully rotated etc.) and orientations, makes the bolts easier to reach from the sides of the pipeline (or manway?)with wrenches working below and above the line, and also makes for a uniform and altogether not unpleasant appearance as pictured.