Received-SPF: pass
 receiver=logan.com; client-ip=205.152.59.71; envelope-from=ceengland@bellsouth.net
Message-ID: <428A9C6F.8090805@bellsouth.net>
Date: Tue, 17 May 2005 20:37:51 -0500
From: Charlie England <ceengland@bellsouth.net>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax)
MIME-Version: 1.0
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: I need misc engine parts
References: <list-946462@logan.com>
In-Reply-To: <list-946462@logan.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Russell Duffy wrote:

>          What length and diameter do you need exactly?
>
>          200 mm M8 studs are an off-the-shelf item, for example. So are
> 200mm M8 bolts with 101,000 psi rating.
>
>          McMaster Carr has a pretty good stock of this sort of thing.
>
>  
> Hi Bill,
>  
> The bolts are M10 x 1.0 thread, which seems to be the problem.   I 
> took a very quick look at the bolts from the dissected single rotor, 
> and they're about 140mm for the longest, and maybe 135mm for the 
> others.  Note, this was not carefully measured, so don't anyone go 
> buying bolts based on this. 
>  
> The only thing I could find at McMaster Carr was full threaded studs, 
> with the description below.  It works out to about $8 per stud.  I was 
> able to buy one set of custom manufactured bolts recently, and they 
> should be here any day.  They were $116, so just about inline with 
> using homemade studs I guess.  I have to believe there's a sources 
> for the exact bolts we need, but I haven't been motivated enough to 
> find it yet.  
>  
> Cheers,
> Rusty


Anyone care to do the math on the stress on each bolt used to hold a 
6.5B together? I'm no engineer but I do know one & he has pointed out 
that if stresses are well below the danger zone, rolled threads vs. cut 
threads just ain't that big a deal. (To back that up, he's flown with 
re-cut prop bolts on wood props for probably more hours than I have 
total time.)

 Remember, factory 13B bolts seem to break with some regularity in high 
power operation & I assume they are rolled, not cut. To me, that says 
that conventional wisdom might not be the end-all best measuring stick.

Charlie