Rod alignment

[ursus]

Originally Posted by nkaminar

What Pete is talking about is called a stress riser and any mechanical engineer knows about them. The notch concentrates the stress and thereby the stress is more than in the bulk of the material at that point. A sharp notch make more concentration. You can think about this in the way glass is cut. Glass is a brittle material. The glass cutting tool makes a sharp groove in the surface of the glass and it breaks easily at that notch. Another way to think about it is how flowing air would crowd around a protrusion in a duct. The flow of stress works the same way, crowding around the notch.

I have to ask about another area where a notch often forms: on rear axle shafts where the seal riding on the shaft can form a concentric groove. Would this create a stress riser that might cause the axle to separate at the groove, with possibly catastrophic results? I've seen guys fill in the groove with JB-Weld and sand it smooth in order to restore the surface dimension but how risky is that?