[UK-CONTEST] Gin Poles/Falling Derricks

[John Wayman]

The ones with the 'weakening slot' are very much stiffer and therefore much less likely to break if they are assembled with the bolt flanges aligned with the plane of lifting, so the flanges are straight up and straight down before the lift begins.
Of course, it's much easier to fit and tighten the bolts with them 90 degrees round, but that is the least stiff and therefore most likely to break way round.
It really does make a huge difference.

73,
John, G4DRS
(Chartered Mechanical Engineer)


________________________________
From: Tom Boucher <tom at telemetry.demon.co.uk>
To: uk-contest at contesting.com
Sent: Wednesday, 23 June, 2010 11:51:49
Subject: [UK-CONTEST] Gin Poles/Falling Derricks

Does anyone know a source of external 2 inch mast couplers without that weakening slot? They do exist because I have one. I also have some internal expanding couplers which are probably stronger than the external things. 

Tom G3OLB
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