<html><head></head><body><p dir="ltr">Use 6061-T6 aluminum where possible. Hard anodize your aluminium parts, and protect them with zinc anodes. Use stainless fasteners coated in a corrosion inhibiting grease, and use stainless helicoil thread inserts in blind tapped holes.</p>
<p dir="ltr">Sean<br>
</p>
<br><br><div class="gmail_quote">On March 23, 2015 6:59:20 AM MDT, Alec Smyth 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 dir="ltr">Ah, I have pondered something related for ages. I have an aluminum bow dome retaining ring bolted to an aluminum seat. I used aluminum screws, to reduce galvanic pair issues. And then I broke off one of the screws by pure clumsiness. I will have to drill this out, as there's virtually no stub, and will probably end up with one screw larger than the rest if I need to re-tap. But my question is... would you guys recommend using aluminum screws in this scenario? I am not really concerned about their holding power, there's a large quantity of screws involved.<div><br /></div><div>Best,</div><div><br />Alec</div></div><div class="gmail_extra"><br /><div class="gmail_quote">On Sun, Mar 22, 2015 at 3:09 PM, Adam Lawrence via Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>></span> wrote:<br /><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc
solid;padding-left:1ex"><u></u>
<div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial">Hi guys,</font></span></div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial"></font></span> </div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial">There really isn't an appreciable difference
in performance between coarse and fine threads. The more important
questions are bolt/nut material, thread engagement and
torque.</font></span></div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial"></font></span> </div>
<div dir="ltr" align="left"><span><font color="#0000ff" face="Arial">The argument for sticking with coarse threads would be that
you reduce the chance for cross threading the wrong bolt during assembly, since
coarse threads are predominately used.</font></span></div>
<div><font color="#0000ff" face="Arial"></font> </div>
<div><span></span><font face="Arial"><font color="#0000ff"><font>A<span>dam</span></font></font></font><br /></div>
<div lang="en-us" dir="ltr" align="left">
<hr />
<font face="Tahoma"><b>From:</b> Personal_Submersibles
[mailto:<a href="mailto:personal_submersibles-bounces@psubs.org" target="_blank">personal_submersibles-bounces@psubs.org</a>] <b>On Behalf Of </b>Sean T
Stevenson via Personal_Submersibles<br /><b>Sent:</b> Sunday, March 22, 2015 1:13
PM<span class=""><br /><b>To:</b> Personal Submersibles General Discussion<br /><b>Subject:</b> Re:
[PSUBS-MAILIST] coarse vs fine thread<br /></span></font><br /></div><div><div class="h5">
<div></div>
<p dir="ltr">Helicoils are an option.</p>
<p dir="ltr">Sean<br /></p><br /><br />
<div class="gmail_quote">On March 22, 2015 11:58:31 AM MDT, Rick Patton via
Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:
<blockquote class="gmail_quote" style="PADDING-LEFT:1ex;MARGIN:0pt 0pt 0pt 0.8ex;BORDER-LEFT:rgb(204,204,204) 1px solid">
<div dir="ltr">
<div>Hank</div>
<div><br /></div>Fine is the only way to go as aluminum is a much softer metal
than steel so it will strip much easier so the more metal you grab, the
better, which fine threads will give you.
<div><br /></div>
<div>Rick</div></div>
<div class="gmail_extra"><br />
<div class="gmail_quote">On Sun, Mar 22, 2015 at 5:55 AM, hank pronk via
Personal_Submersibles <span dir="ltr"><<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>></span> wrote:<br />
<blockquote class="gmail_quote" style="PADDING-LEFT:1ex;MARGIN:0px 0px 0px 0.8ex;BORDER-LEFT:#ccc 1px solid">Help
I need advice!<br />My new bow dome will be secured to the Al mating ring with
straps. I am laying out the bolt holes to be threaded in the AL
ring. My question is, should the bolts be fine or coarse thread? What
holds better in AL ? The threads will be 3/8 by 1 in deep.<br />Thank
you in
advance.<br />Hank<br />_______________________________________________<br />Personal_Submersibles
mailing list<br /><a href="mailto:Personal_Submersibles@psubs.org" target="_blank">Personal_Submersibles@psubs.org</a><br /><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br /></blockquote></div><br /></div>
<p style="MARGIN-BOTTOM:1em;BORDER-BOTTOM:#000 1px solid;MARGIN-TOP:2.5em"></p><pre><hr /><br />Personal_Submersibles mailing list<br /><a href="mailto:Personal_Submersibles@psubs.org" target="_blank">Personal_Submersibles@psubs.org</a><br /><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br /></pre></blockquote></div></div></div></div>
<br />_______________________________________________<br />
Personal_Submersibles mailing list<br />
<a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><br />
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br />
<br /></blockquote></div><br /></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>