<div dir="ltr">Does the window seat have some sort of inside diameter edge? I would think if it does not, then its pretty much guaranteed to slip with or without grease - with grease being the quieter less-terrifying option.<div><br></div><div>Best,</div><div><br></div><div>Alec</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Jul 6, 2015 at 6:50 PM, 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="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
Sean,<br>
Thank you for the input, I think I will just use weights like Alan says.<br>
I am making a fixture to simulate the EPDM gasket compressed under my dome. I want to test it with grease and without. I will squeeze the gasket in the fixture then push the top plate sideways with a pusher bolt to see if the gasket allows movement. I want to make sure my dome can expand and contract at depth.<br>
Hank<br>
--------------------------------------------<br>
On Mon, 7/6/15, Sean T. Stevenson via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br>
<br>
Subject: Re: [PSUBS-MAILIST] calculation<br>
To: "Personal Submersibles General Discussion" <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>
Received: Monday, July 6, 2015, 9:08 AM<br>
<div><div class="h5"><br>
Hank - the force developed is dependent on the<br>
stiffness of both the bolt material and of the specimen<br>
you're pushing on. You can't necessarily equate<br>
this directly to torque because of friction in the bolt<br>
threads and at the bolt end contact, and of course the<br>
elasticity of the bolt itself. You can only estimate it. <br>
There are many online tools for calculating the developed<br>
tensile force in a bolted connection, for example, but these<br>
consider only the bolt as the deformable element, and<br>
require an accurate estimate of coefficients of friction,<br>
and this will change with lubrication. As you complicate the<br>
system, it becomes more geometry dependent.<br>
A 1" - 8 UNC 2A thread is 8 threads per<br>
inch, so a set number of turns will give you the approximate<br>
axial displacement (0.125" per revolution - approximate<br>
because the bolt will change length under load). If you<br>
assume a rigid fixture, then your strain is equal to the<br>
overall change in length (calculated from # of bolt turns),<br>
divided by the gauge length (distance over which the length<br>
change occurs, which would be the length of your specimen<br>
measured between the rigid fixture and the end of your jack<br>
bolt). Compressive or tensile load is then calculated based<br>
on the modulus of elasticity of the specimen. <br>
Alternatively, you can measure the load (make the bolt or<br>
fixture into a load cell or strain gauge the specimen) and<br>
calculate the material properties.<br>
Load, axial displacement, modulus. You need any<br>
two to calculate the third.<br>
What are you making / testing?<br>
Sean<br>
<br>
<br>
<br>
<br>
On July 6, 2015 6:26:49 AM<br>
MDT, hank pronk via Personal_Submersibles<br>
<<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br>
Hi all,<br>
I<br>
need help, can anyone tell me how to calculate how much<br>
force a bolt can push or pull using a torque wrench to turn<br>
the bolt. So how many foot pounds of torque does it take to<br>
rotate a bolt to create 250 lbs push with a 1 in coarse<br>
thread bolt. I need to make a test fixture.<br>
Hank<br>
<br>
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