Sounds plausible to me, regarding the stake marks.
A recent examination of my TR3 axle makes me believe that the stake
marks were manually applied and I wonder if they were always placed
properly.
>----------
>From: Jack W Drews[SMTP:vinttr4@forbin.com]
>Sent: Tuesday, June 10, 1997 9:07 AM
>To: friends of Triumph
>Subject: Axle failure modes
>
>We seem to have a pretty good picture of where these things fail. It's
>inboard of the hub, between the hub and the shoulder, sometimes inside
>the bearing, sometimes outside. We will diminish this problem by
>induction hardening this area. We will not harden the tapered area,
>because the metallurgist who is giving us advice has personal experince
>with failures emanating from keyway corners in hardened parts and
>advises strongly against it.
>
>The failure that puzzles us a little bit is Jeff Snook's, which failed
>inside the hub, at the stake marks.
>
>I'd like to advance a theory on this one, but it is a theory that can
>hardly be verified. For the axle shaft to fail here, the logical
>starting place is the stake marks, which provide an ideal starting point
>for a fatigue failure. Why were there stake marks there? Probably to
>prevent the key from riding up the keyway machining radius while the hub
>is being installed. If the key rode up the radius, the hub would still
>tighten down and you could still apply lots of torque to the nut.
>However, there would be an air space between the hub ID and the axle.
>This would allow axle bending within the hub.
>
>As a result of this thought process, I recommend that we assemble axles
>differently in the future. We should install the hub on the axle and
>then tap the key into the square keyway. A small chamfer ground on the
>end of the keyway will help it start.
>
>Opinions?
>
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