<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_ym19_1_1486343895596_2802"> Hi,</div><div id="yui_3_16_0_ym19_1_1486343895596_2793" dir="ltr">am having trouble Googling an answer to this question.</div><div id="yui_3_16_0_ym19_1_1486343895596_2551" dir="ltr"> I have an O-ring groove in the bore of my light housing, sealing</div><div id="yui_3_16_0_ym19_1_1486343895596_2792" dir="ltr">between the bore & the side of my acrylic lens as per attached diagram.</div><div id="yui_3_16_0_ym19_1_1486343895596_2791" dir="ltr">On a piston O-ring groove it calls for an optimal 2% stretch & not more than 5%.</div><div id="yui_3_16_0_ym19_1_1486343895596_2886" dir="ltr">I can't find any reference to what stretch if any should be, if any, for an o-ring</div><div id="yui_3_16_0_ym19_1_1486343895596_2888" dir="ltr">in a bore groove. I did see that in a rotary application they don't advice that</div><div id="yui_3_16_0_ym19_1_1486343895596_2874" dir="ltr">their should be any pressure on the rotating rod.</div><div id="yui_3_16_0_ym19_1_1486343895596_2887" dir="ltr">Should I be designing so that the o-ring will have a 2% stretch around the lens?</div><div id="yui_3_16_0_ym19_1_1486343895596_2918" dir="ltr">Thanks, Alan</div></div></body></html>