[email protected] wrote:
> Stress relief.
>
> I think deformation of flange holes in aluminum hubs is being
> mis-characterized, leading to incorrect assumptions about effective
> spoke hole position before and after stress relieving and that
> trueness of the wheel suffers from the process.
>
> Hole deformation is an asymptotic effect that with reasonable spoke
> tension is already as deep as it will get. If that were not so,
> spokes would gradually sink through the flange and pull out. Once
> about a third of the spoke diameter bears fully on the flange hole it
> is as deep as it will go while subsequent stress relief cannot "bed
> them in" any deeper as the process is often depicted here. The terms
> bedding in or stabilizing are a misnomers chosen by people who cannot
> visualize mechanical stress relief or that spokes bed in naturally
> from initial spoke tension.
The Rockwell hardness test (B scale, used for materials like aluminum)
uses a 1/16" (1.6mm) steel ball and measures the depth indented with
100kgf. Typical hardness numbers for aluminum would indicate a depth of
around 0.14mm (into a flat surface of reasonable thickness). While the
scenario is a bit different, the dimensions and forces are similar.
Given that the spoke and hole diameters are close and the angle is
small, it seems that the absolute "bedding in" is small and happens
early (with tension). From there it seems safe to assume that stress
relief doesn't cause any significant additional "bedding in".
Perhaps this issue is finally put to bed.