specifying "flatness" of rod or tubing bent into a U-shape
specifying "flatness" of rod or tubing bent into a U-shape
(OP)
Hi all,
I'm scratching my head over how to specify something that seems like it should be simple to do. We've got some 1/2' Dia. rods that are bent into U-shaped pieces where the "horizontal" section of the U is appreciably longer than the vertical legs.The two ends of the U should be co-planar and each be perpendicular to the rod face. The bends should be 90 degrees. My question what datums should I use? I want to be able to specify that when placed on a flat surface there is no more than a certain size gap between the piece and the table anywhere along its length. In other words I want the centerline of the rod to be planar, but I can't figure out how to set up datums to do this. Can I use datums target lines for the (theoretical) line of contact of the piece on a flat table and call that one datum?
Also, Ive seen other references stating that the standard in the tubing industry is to dimension bend radii to the centerline of the tube, not the inside. Is the same true for solid rods?
Thanks much,
I'm scratching my head over how to specify something that seems like it should be simple to do. We've got some 1/2' Dia. rods that are bent into U-shaped pieces where the "horizontal" section of the U is appreciably longer than the vertical legs.The two ends of the U should be co-planar and each be perpendicular to the rod face. The bends should be 90 degrees. My question what datums should I use? I want to be able to specify that when placed on a flat surface there is no more than a certain size gap between the piece and the table anywhere along its length. In other words I want the centerline of the rod to be planar, but I can't figure out how to set up datums to do this. Can I use datums target lines for the (theoretical) line of contact of the piece on a flat table and call that one datum?
Also, Ive seen other references stating that the standard in the tubing industry is to dimension bend radii to the centerline of the tube, not the inside. Is the same true for solid rods?
Thanks much,





RE: specifying "flatness" of rod or tubing bent into a U-shape
... until they buy a measuring arm. Then they go insane.
I'm not sure that GD&T buys you anything on this part, as in being somehow superior to a note to just lay it on a table and go over it with a height gage.
Mike Halloran
Pembroke Pines, FL, USA
RE: specifying "flatness" of rod or tubing bent into a U-shape
Bill
RE: specifying "flatness" of rod or tubing bent into a U-shape
If you are following ASME, envelope requirement is implied; in ISO you can specify it with (E) symbol.
Having dimension with tolerance actually means having “GD&T” on your drawing.
RE: specifying "flatness" of rod or tubing bent into a U-shape
RE: specifying "flatness" of rod or tubing bent into a U-shape
Thanks again.
Bill