<div dir="ltr">Very interesting. I have a mix of extreme duty and standard duty, but all mine are plastic!</div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Sep 23, 2020 at 1:49 PM hank pronk via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div style="font-family:"Helvetica Neue",Helvetica,Arial,sans-serif;font-size:13px"><div></div>
        <div dir="ltr">Alec, I have an actuator with a metal end cap.  I think it is the extreme duty model</div><div dir="ltr">Hank</div><div><br></div>
        
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                    On Wednesday, September 23, 2020, 6:55:22 AM MDT, Alec Smyth via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:
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                <div><div id="gmail-m_9070943026776871384yiv5499238893"><div><div dir="ltr">Oh, that's a good find Alan, I was unaware of the second O ring. My suggestion would be to remove the outer one if going very deep, or drilling a tiny hole between the two. Else the O-ring would tend to squeeze the shaft at depth, freezing it up or increasing current draw. My impression of these actuators is that the likely failure point is the top cap (the disc-shaped piece that ends the main cylinder). Not that pressure would be a problem, but it's a plastic piece and includes the pivot point of the actuator, so is subject to significant mechanical stress.<div><br clear="none"></div></div><br clear="none"><div><div id="gmail-m_9070943026776871384yiv5499238893yqt11978"><div dir="ltr">On Tue, Sep 22, 2020 at 8:17 PM Alan via Personal_Submersibles <<a rel="nofollow" shape="rect" href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div></div><div>Thanks Alec & Hank.</div><div>I found the diagram below that doesn't show any switches.</div><div>I like the idea of air compensating them, perhaps with an over pressure from</div><div>a regulator as Cliff is using on his thrusters.</div><div>The two shaft O-rings are as per the Minnkota, with the outer O-ring doomed</div><div>to fail when the pressure gets high enough. If there was an overpressure  the </div><div>inner O-ring would fail first (hopefully)  leaving the cavity between the two with air.</div><div>Or is it filled with Greece?</div><div>Alan</div><div><img id="gmail-m_9070943026776871384yiv5499238893gmail-m_-1949698290640161963EC618DBF-0D2C-46C6-A89D-A80FF80F3EAE" src="cid:174bc2ac653a75896511" alt="image1.PNG"><br clear="none"></div><div><br clear="none"></div><div><br clear="none">On 23/09/2020, at 10:49 AM, Alec Smyth via Personal_Submersibles <<a rel="nofollow" shape="rect" href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote type="cite"><div><div dir="ltr">Hi Alan,<br clear="none"><div><br clear="none"></div><div>I don't think there are any microswitches in these. Nor in fact any sealed components at all that I saw.</div><div><br clear="none"></div><div>Best,</div><div>Alec</div></div><br clear="none"><div><div dir="ltr">On Tue, Sep 22, 2020 at 5:24 PM Alan via Personal_Submersibles <<a rel="nofollow" shape="rect" href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br clear="none"></div><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div><div></div><div>Alec & Hank,</div><div>when I was compensating linear actuators ( a long time ago ) mine had</div><div>micro switches in them that stopped the travel.</div><div>I am not sure whether the Lenco has them or not!</div><div>I was sticking a hot needle through the plastic housing of the micro switch to</div><div>help compensate them, as it was pretty well sealed & I feared it would randomly</div><div>be switched because of the oil compensation pressure at depth.</div><div>Also the brushed motors were sealed. This again may be a problem if the </div><div>compensating oil hasn't fully filled the cavities inside the motor housing &</div><div>suddenly experiences pressure as you descend. The small brushed motors</div><div>can have what Phil describes as a "herky jerky" action when oil compensated</div><div>due to the oil lifting the brushes off as they spin fast.</div><div>Mentioning this in case you encounter problems operating them at depth!</div><div>Alan</div><div><br clear="none">On 4/09/2020, at 9:59 AM, Alec Smyth via Personal_Submersibles <<a rel="nofollow" shape="rect" href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote type="cite"><div><div dir="ltr">Hi friends,<div><br clear="none"></div><div><span style="color:rgb(29,33,41);font-family:Helvetica,Arial,sans-serif;font-size:14px;white-space:pre-wrap">The PSUBS Community Projects page (</span><a rel="nofollow" shape="rect" href="https://l.facebook.com/l.php?u=http%3A%2F%2Fwww.psubs.org%2Fcommunity%2Fprojects%2F%3Ffbclid%3DIwAR0h2tBfXPDrd1-qg5NcZGBCqXXe-SKQZMxFCDCBBtSNnaZx42iOOmuBdoc&h=AT3eqKa9glmfxaDQHOwwOXbznLIfHpxLe5qW-frl6GayEG2OzsaSaxmS_Lvj8sXs-zLUYglsW2tGlIPlmjmFChFQaJrsRSDyDSjP67nMCWAbJVXw5DZhN8Yvuy2Lo7fTILWUn7Zl_yu7bz745aO0H2hQ8vlO11fvzI6KwLZjoR3NwjUToX81HiSAaM1PZIXKrGrmU052uyrhlWmYSJvAuvs6-p6qLb1DUxTxVjW3bV4I6um6t4a5ug0bACMZ6jRKmjrNrd2v8l_3IpweTripbVuMdD8-Tc2exR8k4WwugJbNH1vY0vmMP-uhazz1sbpYLw9mAmjxHGux3_adPYa01oDxd8JWplw5ucnC9jWUhQI-5XlHQzPGSFeYRl2u5QAGl8p_K2Fllv8DobTp1wUCZ-TrgDFKgeiAscI18UrCE60RnkfHK8al3tGWM4ZnQ-P_vS02FdO4qiC5gReo23KUQ0yrJoUn5iNnF24W07kMUkDpp4JLTdT-WODzylg-xWTxnsScWBnllTV7BkUe3QwkIq_1NHXX9QPl6kmaL8b4QpNb1KtjXN3oLdkiC3JN0B3TAch0mA3yRZaEsJSG07y8j6RemPfbNs0-LHZh5j4EK7Sw_j6CWmJwViWoS5TPftPt0tsz7hg" style="color:rgb(56,88,152);text-decoration-line:none;font-family:Helvetica,Arial,sans-serif;font-size:14px;white-space:pre-wrap" target="_blank">http://www.psubs.org/community/projects/</a><span style="color:rgb(29,33,41);font-family:Helvetica,Arial,sans-serif;font-size:14px;white-space:pre-wrap"> ) now features an "open source manipulator" developed by Hank Pronk and me. This is an intentionally simple manipulator built using only a drill press and an angle grinder, except for a few plastic bushings that were turned on a lathe for expedience. We purposely avoided things like aluminum welding, to keep it's fabrication as accessible as possible. The page contains blueprints, photos, and a bill of materials - but I recommend beginning at the "Start Here" document in the ZIP file. Please don't hesitate to reach out if you have any questions, or if you have any suggested improvements.</span><br clear="none"></div><div><br clear="none"></div><div>Best,</div><div>Alec</div></div>
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