[CR]Curved cranks

(Example: Framebuilding:Brazing Technique)

Date: Fri, 30 Jun 2006 16:40:56 -0400 (EDT)
From: "Greg Lone" <gwlone@yahoo.ca>
To: classicrendezvous@bikelist.org
Subject: [CR]Curved cranks

Hi group ,I noticed a posting to the Curved Cranks thread that mentioned older fly wheel and machinery wheels used curved spokes. I have been told by the "old hands" in the antique machinery hobby , that this was done to relive stress as large ,thin section castings cooled in the foundry. The hubs of such wheels contain less mass and therefore cool faster than the rims, this sets up considerable stress in the spokes. Cast iron; the predominate material of the time, is very weak in tension. Straight spokes resulted in many scrap castings,therefore curved spokes were developed to prevent this loss. Obviously not the case with the curved crank arms, but an interesting thought none the less. Greg Lone Langley B.C. Canada

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