REFLECTOR:Seat Belt Hardpoints
Al Gietzen
reflector@tvbf.org
Mon, 10 Nov 2003 08:06:51 -0800
This is a multi-part message in MIME format.
------=_NextPart_000_002F_01C3A761.98C37B00
Content-Type: text/plain;
charset="us-ascii"
Content-Transfer-Encoding: 7bit
Hardware stores should carry the size bolts to fit the belts to your
hard points - a Grade 5 should do the trick.
Best regards,
Scott B.
The manual calls for 5/16" in the hardpoints. Now consider this. If a
coarse thread 5/16 (grade 5) is adequate for the floor/keel hardpoints,
why is there a 7/16 fine thread high grade bolt in the carbon beam for
the shoulder belt? If you use a standard 3-pont restraint (cross-chest
shoulder belt), the attach point at the keel side takes the load of both
the shoulder and the lap belt. And with a major frontal impact, it may
be possible for a person to survive a 12-15 G loading on the belts: half
of which has to be held by the keel side hardpoint. Now, for me (200#);
that's about 1200-1300 lbs. A bending load on that 5/16 bolt could
result in stress levels of about 50,000 psi. Now how does the grade 5,
coarse thread bolt look?
The accompanying question is the strength of the hardpoint itself. Back
when Mark was still with Velocity, he and I had discussed this issue,
and he assured me some load tests would be done to assure the adequacy
of that hardpoint and the 5/16 bolt, whenever time allowed. Apparently
time didn't allow before he left. Did this testing ever get done at
Velocity? Scott? Has anyone loaded that hardpoint to 1200 #+ to see
what happens. Has there ever been a failure noted of the hardpoint in
any accidents that have occurred? Or am I way off in my cursory
analysis?
I don't know that this is a problem; I think it could be. In any case,
be sure to do a good job glassing in that hardpoint, and it wouldn't
hurt to use a 7/16 AN bolt there.
My manual called for 5/16" hard points, which I installed. I just
ordered and recieved my belts from Velocity and the bolts are 7/16"!!!
And the days turn to years.
Mel Bina STD RG
------=_NextPart_000_002F_01C3A761.98C37B00
Content-Type: text/html;
charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<META HTTP-EQUIV=3D"Content-Type" CONTENT=3D"text/html; =
charset=3Dus-ascii">
<meta name=3DGenerator content=3D"Microsoft Word 10 (filtered)">
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Verdana;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:blue;
text-decoration:underline;}
span.EmailStyle17
{font-family:Verdana;
color:blue;
font-weight:normal;
font-style:normal;
text-decoration:none none;}
@page Section1
{size:8.5in 11.0in;
margin:1.0in 1.25in 1.0in 1.25in;}
div.Section1
{page:Section1;}
-->
</style>
</head>
<body bgcolor=3Dwhite lang=3DEN-US link=3Dblue vlink=3Dblue>
<div class=3DSection1>
<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D3 =
face=3D"Times New Roman"><span
style=3D'font-size:12.0pt'> </span></font></p>
<div>
<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial'>Hardware stores should =
carry the
size bolts to fit the belts to your hard points - a Grade 5 should do =
the
trick.</span></font></p>
</div>
<div>
<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial'>Best =
regards,</span></font></p>
</div>
<div>
<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial'>Scott B.</span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'>The manual calls for 5/16” =
in the hardpoints.
Now consider this. If a coarse thread 5/16 (grade 5) is adequate =
for the
floor/keel hardpoints, why is there a 7/16 fine thread high grade bolt =
in the
carbon beam for the shoulder belt? If you use a standard 3-pont =
restraint
(cross-chest shoulder belt), the attach point at the keel side takes the =
load
of both the shoulder and the lap belt. And with a major frontal =
impact,
it may be possible for a person to survive a 12-15 G loading on the =
belts: half
of which has to be held by the keel side hardpoint. Now, for me =
(200#);
that’s about 1200-1300 lbs. A bending load on that 5/16 bolt =
could
result in stress levels of about 50,000 psi. Now how does the =
grade 5,
coarse thread bolt look?</span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'> </span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'>The accompanying question is the
strength of the hardpoint itself. Back when Mark was still with =
Velocity, he
and I had discussed this issue, and he assured me some load tests would =
be done
to assure the adequacy of that hardpoint and the 5/16 bolt, whenever =
time
allowed. Apparently time didn’t allow before he left. =
Did
this testing ever get done at Velocity? Scott? Has anyone =
loaded
that hardpoint to 1200 #+ to see what happens. Has there ever been =
a
failure noted of the hardpoint in any accidents that have =
occurred? Or am
I way off in my cursory analysis?</span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'> </span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'>I don’t know that this is a
problem; I think it could be. In any case, be sure to do a good =
job glassing
in that hardpoint, and it wouldn’t hurt to use a 7/16 AN bolt =
there.</span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'> </span></font></p>
<p class=3DMsoNormal><font size=3D2 color=3Dblue face=3DVerdana><span =
style=3D'font-size:
11.0pt;font-family:Verdana;color:blue'> </span></font></p>
</div>
<blockquote style=3D'border:none;border-left:solid black =
1.5pt;padding:0in 0in 0in 3.0pt;
margin-left:3.0pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'>=
<div>
<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D3 =
face=3D"Times New Roman"><span
style=3D'font-size:12.0pt'> </span></font></p>
</div>
<p class=3DMsoNormal style=3D'margin-left:.5in'><font size=3D2 =
face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial'>My manual called for =
5/16" hard
points, which I installed. I just ordered and recieved my belts =
from
Velocity and the bolts are 7/16"!!! And the days turn to =
years. <br>
<br>
Mel Bina STD RG</span></font><font face=3DArial><span
style=3D'font-family:Arial'> </span></font></p>
</blockquote>
</div>
</body>
</html>
------=_NextPart_000_002F_01C3A761.98C37B00--