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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>
<br>
<br>
On 2017-09-16 11:14, hank pronk via Personal_Submersibles wrote:<br>
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<blockquote type="cite" cite="mid:tGlcdUK8zlKVFtGlddR4sC">
<div style="font-family:Helvetica Neue, Helvetica, Arial,
sans-serif;font-size:13px;">
<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>
<div><br>
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<div id="yahoo_quoted_5872733806" class="yahoo_quoted">
<div style="font-family:'Helvetica Neue', Helvetica, Arial,
sans-serif;font-size:13px;color:#26282a;">
<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><br>
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<div id="yiv1407130957">
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<div
style="color:#000;background-color:#fff;font-family:verdana,
helvetica, sans-serif;font-size:13px;">
<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>
<div class="yiv1407130957qtdSeparateBR"
id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3499"><br
clear="none">
</div>
<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">
</div>
<div class="yiv1407130957qtdSeparateBR"
id="yiv1407130957yui_3_16_0_ym19_1_1505579519970_3499">Greg
Cottrell</div>
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