Date:         Wed, 4 Aug 2010 16:41:20 -0400
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Swage Bit + Bolt for Pop Top Cable. Strong enough?
Comments: To: neil n <musomuso@GMAIL.COM>
In-Reply-To:  <AANLkTi=HNTMzopAYOYt-Ga32M3T4F61R_4U83H5=ZwvD@mail.gmail.c om>
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At 12:03 AM 8/4/2010 Wednesday, neil n wrote:
>Would bending this stainless part ~ 45* weaken the metal to much to be
>useable in this application?

I'd like to suggest you think (and measure) very carefully about
this.  These fittings are intended to be used in pivoting
applications where the tension is always along the axis of the
fitting.  If there is even slight  repetitive bending of the wire
where it exits the swage it will be liable to early fatigue
failure.  I'd suggest that it *might* be better to shorten the
fitting to keep the exit point where it is in the original, and also
to consider the thickness of the fitting and how it affects the lead
at the exit. If the joint is absolutely static under operation these
considerations are much less, i.e. I don't see a one-time small-angle
bend to pose a major problem.  The fitting has a working load of ~250
kg at 3:1 margin, and the eye is the weak point -- clearly a swage
length at least as long as the original should suffice.  I presume
you'll be using 7x19 wire for flexibility -- 1x19 isn't meant for
running over sheaves.


>Would a 5 mm bolt in that application be strong enough not to shear?

Here's a page that will help you calculate the shear loading:
http://www.roymech.co.uk/Useful_Tables/Screws/Bolted_Joint.html

To get useful answers I think you'll have to determine the spring
rate (force per unit compression) and total compression.

Yours,
David