<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><div>Smart.  </div><div><br>On Sep 16, 2017, at 1:29 PM, Sean T. Stevenson via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div>
  
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    <div class="moz-cite-prefix">Don't ask.  Draw.  Create a proper
      manufacturing drawing with the material and all of the required
      tolerances indicated.  Use GD&T where applicable.  Roundness,
      sphericity, etc. all specified on the drawing.  When you make a
      request for quote, it's as simple as "one part manufactured per
      supplied drawing # nnnnnn".  They quote against the drawing, and
      if they make a part that doesn't match the drawing, you don't pay
      for it.  Simple.<br>
      <br>
      Sean<br>
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      On 2017-09-16 11:14, hank pronk via Personal_Submersibles wrote:<br>
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        <div>Greg,</div>
        <div>The problem with calling it a vacuum tank is the
          sphericity.  ASME is not as fussy as ABS for sphericity, and
          if you ask for the proper sphericity the cat is out of the
          bag.  </div>
        <div>Hank</div>
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            <div> On Saturday, September 16, 2017, 10:50:57 AM MDT,
              james cottrell via Personal_Submersibles
              <a class="moz-txt-link-rfc2396E" href="mailto:personal_submersibles@psubs.org"><personal_submersibles@psubs.org></a> wrote: </div>
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                    <div id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3161"><span id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3495">Hi David,</span></div>
                    <div id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3161"><span><br clear="none">
                      </span></div>
                    <div id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3161"><span id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3496">In my experience
                        it was cheaper and faster to hire an ASME tank
                        fabricator to produce a steel cylinder with the
                        head (or heads) welded on. Mine came machine
                        welded with an ASME code stamp. </span></div>
                    <div dir="ltr" id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3161"><span id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3519">If your design
                        will feature external frames, ask them for both
                        heads welded on. If your design will feature
                        internal frames (done later) ask them to weld
                        one end only. This will be cheaper in the long
                        run and better built. It's hard to beat pressure
                        vessel code machine welding. Specify NO backing
                        strips.</span></div>
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                    <div class="yiv1407130957qtdSeparateBR" id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3499">Another
                      tip- call it a "vacuum tank".</div>
                    <div class="yiv1407130957qtdSeparateBR" id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3499"><br clear="none">
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                    <div class="yiv1407130957qtdSeparateBR" id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3499">Greg
                      Cottrell</div>
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