Re: Why piping GA are in 1:33 scale?

Hi L.

In the olden days.... the "plastic" model was built for 3-D, inteference, construction etc, that scale was 1:33 1/3. That is why the GA's were drawn on that scale. Even now it is still used with the CAD models drawings. The scale rules can still be obtained. Although I see them less these days. Not an old hand myself though but above is true.

Raymond Metselaar
PDMS Designer
Holland

• In PipingDesign@yahoogroups.com, Richard Beale <r_beale@...> wrote:
  >
  > Hi L.
  > In the "old days", in Canada anyway, we used to draw (manual
  drawings of
  > course) in imperial measurements at a scale of 3/8" to 1'-0", which
  > corresponds to 1:32. I can't speak for the rest of the world, but
  when
  > Canada went metric in the late 1970's we started drawing at the
  closest
  > rounded equivalent of 1:30. 1:30 (and 3/8" to 1'-0" before it) has
  > proved to be the most convenient scale to maintain clarity of the
  detail
  > on a drawing of "A1" metric size or "D" imperial size sheet of
  paper.
  > 1:50 would mean less drawing sheets, but the smaller detail may be
  lost.
  > 1:25 means greater detail, but larger items are larger than needed,
  and
  > results in more drawing sheets.
  >
  > 1:33 is very close to 1:30, so the above applies here also. I have
  a old
  > scale rule kicking around that has 1:33 1/3 on it. Off the top of my
  > head I can't remember the reason for this, although obviously there
  is
  > one. Maybe one of the other old timers can remember. I'm going to
  go dig
  > this scale up. Maybe then I'll remember the rational.
  >
  > Regards,
  > Richard B.
  > Calgary, Canada
  >
  >
  >
  >
  > -----Original Message-----
  > From: PipingDesign@yahoogroups.com
  [mailto:PipingDesign@yahoogroups.com]
  > On Behalf Of Lakshaboopathy Subramanian
  > Sent: January 20, 2008 12:23 PM
  > To: PipingDesign
  > Subject: [PipingDesign] Why piping GA are in 1:33 scale?
  >
  >
  >
  > Anyone can explain why the piping GA are making in 1:33 scale?
  > we can make it in 1:25 or 1:50. How the odd number 33 came to the
  > picture?
  >
  > Thanks and regards,
  > L.Subramanian.
  >
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