<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_ym18_1_1458848729393_2712"><span id="yui_3_16_0_ym18_1_1458848729393_2769">Hank,</span></div><div id="yui_3_16_0_ym18_1_1458848729393_2710"><span id="yui_3_16_0_ym18_1_1458848729393_2711">I left out some details on that drawing. The back end fits the same</span></div><div id="yui_3_16_0_ym18_1_1458848729393_2758" dir="ltr"><span id="yui_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 id="yui_3_16_0_ym18_1_1458848729393_2789" dir="ltr"><span>bolt in to the central housing. </span></div><div id="yui_3_16_0_ym18_1_1458848729393_2790" dir="ltr"><span>Alan</span></div><div id="yui_3_16_0_ym18_1_1458848729393_2756"><span></span><br></div><div class="qtdSeparateBR" id="yui_3_16_0_ym18_1_1458848729393_2707"><br><br></div><div class="yahoo_quoted" id="yui_3_16_0_ym18_1_1458848729393_2705" style="display: block;"> <div id="yui_3_16_0_ym18_1_1458848729393_2704" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym18_1_1458848729393_2703" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym18_1_1458848729393_2706" dir="ltr"> <font id="yui_3_16_0_ym18_1_1458848729393_2709" face="Arial" size="2"> <hr size="1" id="yui_3_16_0_ym18_1_1458848729393_2708"> <b><span style="font-weight: bold;">From:</span></b> hank pronk via Personal_Submersibles <personal_submersibles@psubs.org><br> <b><span style="font-weight: bold;">To:</span></b> Personal Submersibles General Discussion <personal_submersibles@psubs.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Friday, March 25, 2016 1:31 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] MK 2 Brushless Thruster<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_ym18_1_1458848729393_2702"><br><div id="yiv0969573453"><div id="yui_3_16_0_ym18_1_1458848729393_2701"><div id="yui_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="yiv0969573453yui_3_16_0_1_1458822019452_3535"><span>Hi Alan,</span></div><div id="yiv0969573453yui_3_16_0_1_1458822019452_3488" dir="ltr"><span id="yiv0969573453yui_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 id="yiv0969573453yui_3_16_0_1_1458822019452_3488" dir="ltr"><span>Hank</span></div> <div class="yiv0969573453qtdSeparateBR" id="yui_3_16_0_ym18_1_1458848729393_2800"><br clear="none"><br clear="none"></div><div class="yiv0969573453yahoo_quoted" id="yui_3_16_0_ym18_1_1458848729393_2699" style="display: block;"> <div id="yui_3_16_0_ym18_1_1458848729393_2698" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12px;"> <div id="yui_3_16_0_ym18_1_1458848729393_2697" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div class="yiv0969573453yqt7524366994" id="yiv0969573453yqt52638"><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="yiv0969573453y_msg_container" id="yui_3_16_0_ym18_1_1458848729393_2696"><div id="yiv0969573453"><div id="yui_3_16_0_ym18_1_1458848729393_2695"><div id="yui_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="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4233"> This is my latest brushless thruster design for scrutiny.</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4199">The last thruster I made was 2 piece with one seal.</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4332">I machined the last version out of aluminum rod, which was expensive & difficult.</div><div id="yiv0969573453yui_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 id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4371" dir="ltr">that I intend to have welded to the propeller end. The back end is bolted on.</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4334" dir="ltr">Am I likely to get distortion when welding the two sections together? There is a sleeve</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4333" dir="ltr">press fitting to help give it some rigidity for welding. Should I make a jig to clamp it in</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4367" dir="ltr">for welding?</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4372" dir="ltr">The thruster is for 500ft depth & is oil filled with a slight over pressure above ambient. </div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4490" dir="ltr">Oil filled mainly for cooling purposes, but also as a secondary defense against any leaks,</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4555" dir="ltr">& for lubrication of bearings & seals. I am using low pressure lip seals & have a double </div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4565" dir="ltr">seal redundant arrangement. The outboard seal is orientated to keep the oil in & with the</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_4612" dir="ltr">internal overpressure should keep the water out. The outboard seal should fail first as it is </div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5135" dir="ltr">exposed to abrasives, especially in sea water. The inboard seal is oriented so that it keeps</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5246" dir="ltr">any water out that may get past the outboard seal. </div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5265" dir="ltr">The tube coming out of the seal cavity is for pressurizing it & for collecting any water that</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5247" dir="ltr">may get through & come out of suspension. I am thinking of putting a water sensor in there.</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5383" dir="ltr">Any comments welcome.</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5384" dir="ltr">Alan</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5281" dir="ltr">p.s. if image isn't big enough keep hitting ctrl & + TO ENLARGE.</div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5112" dir="ltr"><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5539"><br clear="none"></div><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5494" style="display: block;"><div class="yiv0969573453yahoo-compose-assist-image-card yiv0969573453ymail-preserve-class" id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5541" style="width: 100%;"><div id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5540"><img id="yiv0969573453yui_3_16_0_ym18_1_1458793494416_5551" style="width: 100%; vertical-align: middle; max-height: 406px; max-width: 800px;" alt="motor cut away.jpg" data-id="5c3cf8d7-7926-b165-f828-9bf050290c4d" itemprop="contentUrl"></div></div></div><div id="yiv0969573453yui_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 href="mailto:Personal_Submersibles@psubs.org" target="_blank" rel="nofollow" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" rel="nofollow" shape="rect">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><div class="yqt7524366994" id="yqt97447">_______________________________________________<br clear="none">Personal_Submersibles mailing list<br clear="none"><a href="mailto:Personal_Submersibles@psubs.org" shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br clear="none"><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></div><br><br></div> </div> </div> </div></div></body></html>