【转帖】line type question

yang686526

line type question
when indicating that two (or more) hole centers are aligned, is the extension line between them drawn as a centerline or a solid line?  for example if three mounting holes on one side of an item are directly aligned with three others on the other side, what kind of line goes between them to indicate this?
thanks,
dan
check out our whitepaper library.
if the centers fall (normal view) onto a line or their axes are coincident (side view), use a centerline.
believe it if you need it or leave it if you dare.fff"> - robert hunter

i agree - center line
  
dave d.
centerline.
v
centerline. don't confuse it with a phantom line, i see this all the time.
chris
solidworks/pdmworks 08 3.1
autocad 06/08
thanks.
dan
a bit late to the party but i also say center line/centre line.
kenat, probably the least qualified checker you'll ever meet...
it might depend on how you are preparing the drawing.  the computer will normally default to a centerline to connect the circles.  however, as i recall back in the 'good ol days' of board type drawings the convention was to make it an extension line once it exceeded the boundaries of the circle being located.  so one might logically ask:  board or computer drawing?
  this may true, ringman.  i can't locate a good source one way or the other.  however, when i located more than one hole, if common, a centerline was used to connect those holes.  once beyond the holes being located, a thin, solid extension line was used.  that's just the way i was taught, i guess.
  i've seen board drawings where a centerline was used instead of an extension line, and they just never looked right to my eye.
believe it if you need it or leave it if you dare.fff"> - robert hunter

agree the cl should only go up to the edge of the holes (maybe a tiny bit beyond) and from there a solid leader line to the dimension.
our cad system more or less does this by default.
kenat, probably the least qualified checker you'll ever meet...
using the same concept as a bolt circle, i'd use a centerline to show the relationship as they share a common design axis (fig. 2-4, 3-25, 4-6, 5-25, 5-52 to name a few).  similarly, for holes aligned along a common plane, the centerline is the right line (y14.5m-1994 figs 1-51 thru 1-56).  coplanar features would use a phantom line to establish a relationship.  solid lines are for showing actual geometries and for leader/extension lines leading to notes and dimensions.  i don't recall if that's from y14.2 or an old drafting text.  if you wanted to locate that common axis wrt another feature, then you would put a solid dimension line extending from the centerline (figs. 5-52 & 5-53).
jim sykes, p.eng, gdtp-s
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