<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px"><div id="yui_3_16_0_ym18_1_1458842677313_4585"><span>Alan,</span></div><div id="yui_3_16_0_ym18_1_1458842677313_4585" dir="ltr"><span id="yui_3_16_0_ym18_1_1458842677313_4735">I like the two seals also and now that you mention you are putting in a fill plug to vent air-I am with you. I would get it welded before you machine the </span>bearing seats etc, if possible.</div><div id="yui_3_16_0_ym18_1_1458842677313_4585" dir="ltr">I would still make both ends bolt together-there is nothing like having it come apart to work on it. My Perry thrusters break down into a million pieces and it is real nice to work on.</div><div id="yui_3_16_0_ym18_1_1458842677313_4585" dir="ltr">Hank</div> <div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"><font size="2" face="Arial"> On Thursday, March 24, 2016 1:55 PM, Alan James via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br></font></div> <br><br> <div class="y_msg_container"><div id="yiv9441703398"><div><div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"><div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2712"><span id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2769">Hank,</span></div><div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2710"><span id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2711">I left out some details on that drawing. The back end fits the same</span></div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2758"><span id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2757">as the front & has a radial o-ring seal on the end housing & 6 cap screws that</span></div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2789"><span>bolt in to the central housing. </span></div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2790"><span>Alan</span></div><div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2756"><span></span><br clear="none"></div><div class="yiv9441703398qtdSeparateBR" id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2707"><br clear="none"><br clear="none"></div><div class="yiv9441703398yahoo_quoted" id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2705" style="display:block;"> <div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2704" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2703" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div class="yiv9441703398yqt3439157887" id="yiv9441703398yqt32133"><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2706"> <font id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2709" face="Arial" size="2"> </font><hr id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2708" size="1"> <b><span style="font-weight:bold;">From:</span></b> hank pronk via Personal_Submersibles <personal_submersibles@psubs.org><br clear="none"> <b><span style="font-weight:bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br clear="none"> <b><span style="font-weight:bold;">Sent:</span></b> Friday, March 25, 2016 1:31 AM<br clear="none"> <b><span style="font-weight:bold;">Subject:</span></b> Re: [PSUBS-MAILIST] MK 2 Brushless Thruster<br clear="none"> </div> <div class="yiv9441703398y_msg_container" id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2702"><br clear="none"><div id="yiv9441703398"><div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2701"><div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2700" style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;background-color:rgb(255, 255, 255);"><div id="yiv9441703398yui_3_16_0_1_1458822019452_3535"><span>Hi Alan,</span></div><div dir="ltr" id="yiv9441703398yui_3_16_0_1_1458822019452_3488"><span id="yiv9441703398yui_3_16_0_1_1458822019452_3487">It wouldn't hurt to clamp the end cap tight but you do have a nice shoulder for the end cap to sit on. Any time I make a part that can and usually does warp, I make it oversize and machine it true after welding. I am curious why you want to weld it-that big shoulder has room for an o-ring. I would also ditch the second seal-it is an air trap. Great project!</span></div><div dir="ltr" id="yiv9441703398yui_3_16_0_1_1458822019452_3488"><span>Hank</span></div> <div class="yiv9441703398qtdSeparateBR" id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2800"><br clear="none"><br clear="none"></div><div class="yiv9441703398yahoo_quoted" id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2699" style="display:block;"> <div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2698" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;"> <div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2697" style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div class="yiv9441703398yqt7524366994" id="yiv9441703398yqt52638"><div dir="ltr"><font face="Arial" size="2"> On Thursday, March 24, 2016 12:27 AM, Alan James via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br clear="none"></font></div> <br clear="none"><br clear="none"> <div class="yiv9441703398y_msg_container" id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2696"><div id="yiv9441703398"><div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2695"><div id="yiv9441703398yui_3_16_0_ym18_1_1458848729393_2694" 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="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4233"> This is my latest brushless thruster design for scrutiny.</div><div id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4199">The last thruster I made was 2 piece with one seal.</div><div id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4332">I machined the last version out of aluminum rod, which was expensive & difficult.</div><div id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4331">The end pieces in this design are from solid rod but the mid section is from a stock tube</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4371">that I intend to have welded to the propeller end. The back end is bolted on.</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4334">Am I likely to get distortion when welding the two sections together? There is a sleeve</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4333">press fitting to help give it some rigidity for welding. Should I make a jig to clamp it in</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4367">for welding?</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4372">The thruster is for 500ft depth & is oil filled with a slight over pressure above ambient. </div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4490">Oil filled mainly for cooling purposes, but also as a secondary defense against any leaks,</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4555">& for lubrication of bearings & seals. I am using low pressure lip seals & have a double </div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4565">seal redundant arrangement. The outboard seal is orientated to keep the oil in & with the</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_4612">internal overpressure should keep the water out. The outboard seal should fail first as it is </div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5135">exposed to abrasives, especially in sea water. The inboard seal is oriented so that it keeps</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5246">any water out that may get past the outboard seal. </div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5265">The tube coming out of the seal cavity is for pressurizing it & for collecting any water that</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5247">may get through & come out of suspension. I am thinking of putting a water sensor in there.</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5383">Any comments welcome.</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5384">Alan</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5281">p.s. if image isn't big enough keep hitting ctrl & + TO ENLARGE.</div><div dir="ltr" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5112"><div id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5539"><br clear="none"></div><div id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5494" style="display:block;"><div class="yiv9441703398yahoo-compose-assist-image-card yiv9441703398ymail-preserve-class" id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5541" style="width:100%;"><div id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5540"><img id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5551" style="width:100%;vertical-align:middle;max-height:406px;max-width:800px;" alt="motor cut away.jpg" itemprop="contentUrl"></div></div></div><div id="yiv9441703398yui_3_16_0_ym18_1_1458793494416_5542"><br clear="none"></div></div></div></div></div><br clear="none">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a rel="nofollow" shape="rect" 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" 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><br clear="none"><div class="yiv9441703398yqt7524366994" id="yiv9441703398yqt97447">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a rel="nofollow" shape="rect" 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" 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"></div><br clear="none"><br clear="none"></div></div> </div> </div> </div></div></div></div><br><div class="yqt3439157887" id="yqt93739">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org" href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a shape="rect" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div><br><br></div> </div> </div> </div></div></body></html>