<html><head></head><body><p dir="ltr">With regard to O-ring sizing, be aware that an O-ring / groove pair is typically designed for a specific limited amount of compression in service, such that the O-ring meets its design fatigue life and tolerance to compression set. Using an O-ring which is larger in cross-section so that it doesn't fall out of an ordinary rectangular groove may, in service, deform the O-ring beyond its elastic deformation limit. So-called "crush" installations are perfectly valid, and are used often in static seals, but any increased compression set as a result of such a design must be accommodated by more stringent maintenance and O-ring changes.</p>
<p dir="ltr">The Parker O-ring Handbook is an excellent design resource, and includes information about typical O-ring failure modes.</p>
<p dir="ltr">Sean<br>
</p>
<br><br><div class="gmail_quote">On October 19, 2014 9:38:49 PM MDT, Alan James via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yiv6418069162"><div><div style="color: rgb(0, 0, 0); font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);"><div id="yiv6418069162yui_3_16_0_6_1413775608229_4"><span id="yiv6418069162yui_3_16_0_6_1413775608229_17">Hi Mark,</span></div><div id="yiv6418069162yui_3_16_0_6_1413775608229_4" style="color: rgb(0, 0, 0); font-size: 16px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span id="yiv6418069162yui_3_16_0_6_1413775608229_19">I have heard of people with the square grove having trouble with the O-ring falling out, & having</span></div><div id="yiv6418069162yui_3_16_0_6_1413775608229_4" style="color: rgb(0, 0, 0); font-size: 16px;
font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-style: normal; background-color: transparent;"><span id="yiv6418069162yui_3_16_0_6_1413775608229_23">to stick them in with copious amounts of grease. That could be a sizing issue though.</span></div><div id="yiv6418069162yui_3_16_0_6_1413775608229_4" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-style:normal;background-color:transparent;" class="yui_3_16_0_1_1413775608229_5111"><span>I think it's a 1/2 dove tail grove they have on the K boats with the angled edge to the outside so that</span></div><div id="yiv6418069162yui_3_16_0_6_1413775608229_4" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande',
sans-serif;font-style:normal;background-color:transparent;" class="yui_3_16_0_1_1413775608229_5111"><span>the O-ring is squashed by external pressure against the flat side of the grove.</span></div><div id="yiv6418069162yui_3_16_0_6_1413775608229_4" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-style:normal;background-color:transparent;" class="yui_3_16_0_1_1413775608229_5111"><span>(someone correct me if I'm wrong)</span></div><div id="yiv6418069162yui_3_16_0_6_1413775608229_4" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-style:normal;background-color:transparent;" class="yui_3_16_0_1_1413775608229_5111"><span>I vaguely remember Phil saying the Deep Workers have the 1/2 dove tail grove.</span></div><div id="yiv6418069162yui_3_16_0_6_1413775608229_4" style="color:rgb(0, 0,
0);font-size:16px;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-style:normal;background-color:transparent;" class="yui_3_16_0_1_1413775608229_5111"><span>Alan</span></div><div id="yiv6418069162yui_3_16_0_6_1413775608229_4" style="color:rgb(0, 0, 0);font-size:16px;font-family:HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif;font-style:normal;background-color:transparent;" class="yui_3_16_0_1_1413775608229_5111"><span><br /></span></div><div id="yiv6418069162yui_3_16_0_6_1413775608229_16"><br clear="none" /></div> <div class="qtdSeparateBR"><br /><br /></div><div class="yiv6418069162yqt8186062180" id="yiv6418069162yqt87523"><div class="yiv6418069162yui_3_16_0_6_1413775608229_8" id="yiv6418069162yui_3_16_0_6_1413775608229_9" style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 16px;"> <div class="yiv6418069162yui_3_16_0_1_1413775608229_2931"
id="yiv6418069162yui_3_16_0_1_1413775608229_3047" style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 16px;"> <div dir="ltr" id="yiv6418069162yui_3_16_0_1_1413775608229_3049"> <hr id="yiv6418069162yui_3_16_0_1_1413775608229_3051" size="1" /> <font id="yiv6418069162yui_3_16_0_1_1413775608229_3050" size="2" face="Arial"> <b><span style="font-weight:bold;">From:</span></b> via Personal_Submersibles <personal_submersibles@psubs.org><br clear="none" /> <b><span style="font-weight:bold;">To:</span></b> personal_submersibles@psubs.org <br clear="none" /> <b><span style="font-weight:bold;">Sent:</span></b> Monday, October 20, 2014 1:03 PM<br clear="none" /> <b><span style="font-weight:bold;">Subject:</span></b> [PSUBS-MAILIST] Conning tower hatch O-Ring<br clear="none" /> </font> </div> <div class="yiv6418069162y_msg_container" id="yiv6418069162yui_3_16_0_1_1413775608229_3046"><br clear="none" />Hello Psubs group,<br
clear="none" /><br clear="none" />I would like to ask the group where I can purchase an O-Ring for a 24" conning tower hatch ring. I also need to mill the slot in the hatch ring and would like to know the width and depth of the slot. I've heard some folks recommend a dove tail slot for the O-ring. <br clear="none" /><br clear="none" />Many thanks for your advise.<br clear="none" /><br clear="none" />Mark...<br clear="none" />_______________________________________________<br clear="none" />Personal_Submersibles mailing list<br clear="none" /><a rel="nofollow" shape="rect" id="yiv6418069162yui_3_16_0_1_1413775608229_3048" ymailto="mailto:Personal_Submersibles@psubs.org" target="_blank" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none" /><a rel="nofollow" shape="rect" id="yiv6418069162yui_3_16_0_1_1413775608229_3045" target="_blank"
href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none" /><br clear="none" /><br clear="none" /></div> </div> </div></div> </div></div></div></div><p style="margin-top: 2.5em; margin-bottom: 1em; border-bottom: 1px solid #000"></p><pre class="k9mail"><hr /><br />Personal_Submersibles mailing list<br />Personal_Submersibles@psubs.org<br /><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br /></pre></blockquote></div></body></html>