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<DIV><FONT face=Arial size=2>My personal experience and observations are that a
hardened, 6-32 socket head screw don't last long on an aileron. A cheap, 6-32
stove bolt (threads all the way to the head)(about $2 box) from the hardware
store USUALLY lasts a very long time. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I don't ever expect to grasp how either one of them
gets broken by that wimpy little balsa flag we refer to as an aileron.
</FONT></DIV>
<DIV>John Ferrell <BR><A
href="http://DixieNC.US">http://DixieNC.US</A><BR></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=jeffghughes@comcast.net href="mailto:jeffghughes@comcast.net">Jeff
Hughes</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, February 14, 2005 9:45
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: 4-40 or 6-32 control
arms?</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Nothing is ever simple. fatigue life of steel is
directly proportional to tensile strength. Fatigue life is also dependent on
surface residual stress. So the best thing you could use is a hardened bolt
with threads rolled after heat treat (good compressive residual
stresses). Like Dean says, finer pitch has a larger root diameter. The trouble
is, the cheap hardware stuff we buy is generally rolled before heat treat, so
it has crappy residual stress (tensile on the surface). So what I try to do is
go large (6-32 or 6-40) and try to find a bolt with a long unthreaded
length (the threads act like stress concentrators).</FONT></DIV>
<DIV><FONT face=Arial size=2>Jeff</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=billglaze@triad.rr.com href="mailto:billglaze@triad.rr.com">Bill
Glaze</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, February 14, 2005 12:47
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: 4-40 or 6-32 control
arms?</DIV>
<DIV><BR></DIV>ED:<BR>A few years ago, there was quite a dialogue about
this. One of the participants was Dick Hanson, a man highly respected
in Pattern and other disciplines. The subject came up about a couple
of individuals who were looking for extra strength on aileron and elevator
actuator bolts. Dick said, specifically, do not get hardened bolts or
anything exotic. He said such material won't stand up under vibration
nearly as well as common rolled thread material, or, for that matter, some
of the standard Home Depot or Lowe's bolts right off the peg board. He
said that the ductility is what prolonged their life; that he had never had
one break. I believed him then, and still do.<BR><BR>Bill
Glaze<BR><BR><A class=moz-txt-link-abbreviated
href="mailto:Rcmaster199@aol.com">Rcmaster199@aol.com</A> wrote:
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<DIV>
<DIV>In a message dated 2/14/2005 12:22:29 AM Eastern Standard Time, <A
class=moz-txt-link-abbreviated
href="mailto:ed_alt@hotmail.com">ed_alt@hotmail.com</A> writes:</DIV>
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<DIV>I've been using 6-32 bolts to make the control horn arms for my 2M
setups so far. It seems like that might be overkill and that 4-40
would suffice. Is it OK to go lighter like this?</DIV>
<DIV> </DIV>
<DIV>Thanks</DIV>
<DIV>Ed A.</DIV></FONT></BLOCKQUOTE></DIV>
<DIV>Ed I wouldn't do that especially on ailerons. I have had 4-40's snap
off like twigs on 90 sized models before. The vibration kills them.</DIV>
<DIV> </DIV>
<DIV>Matt</DIV></FONT></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>