When you measure for end float you measure between one hard stop point and another.But if it is indeed an oversize crank shoulder...and I agree that it's plausible, even likely... I don't understand how the crank had a measured 10 thou assembled end float, and the crank spun with an effortless flick of the fingers...
@concours is right, you have the evidence on this pic where you have 2 arcs showing contact with the cases of something other than the bearing.
Normal tool marks from a low production volume process. Nothing detracting from FFF.Two 'rings' further out seem to have a similar crossover pattern and look like machining marks (from a milling cutter?). The apparent crossover pattern could be an optical illusion caused by reflections from two separate light sources.
The bearing damage as Concours said would have been the result of the bearing shoulder coming into contact with the bearing outer race and the evidence is in the pictures.
Two 'rings' further out seem to have a similar crossover pattern and look like machining marks (from a milling cutter?). The apparent crossover pattern could be an optical illusion caused by reflections from two separate light sources.
The bearing damage as Concours said would have been the result of the bearing shoulder coming into contact with the bearing outer race and the evidence is in the pictures.
The caliper is PLENTY ACCURATE to show the two hundred thousandths error we are discussing here. We can measure & talk microns if you insist, but the feature we are discussing is a simple as-forged (the O.D. Of that feature) raised boss that has been faced off. That O.D. , surface finish and roundness will vary significantly, (even before being bitched-up from rubbing contact with the outer race) because it's not a machined feature.Oops, the cases are shown in the first pics, I should have looked up there too! It does not look like the crank rubbed on the case, the dirty contact surfaces clearly indicate relative movement between bearing and crank. I would recommend careful measurements of the bearing contact surfaces, also the bearing, with real micrometers, not vernier calipers, calipers can easily be off by more than required bearing fit tolerances.
Nah, just decades of experience, working on complex machinery, often without procedures, manuals, specifications or special tools/fixturing.Concours, you have the eyes of an eagle, the wisdom of an owl and the patience of a saint. And the proof of a Perry Mason!
Very glad you and others are part of this forum that have your skill/tech/abilityNah, just decades of experience, working on complex machinery, often without procedures, manuals, specifications or special tools/fixturing.
Every step includes reverse engineering, logic check, devil's advocate & Murphy's law prevention.
Thanks though.
I just try to share this, before I go.
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I have echoed that sentiment since early on.Very glad you and others are part of this forum that have your skill/tech/ability
As we say down here...."your a clever bugger."
NooooooNow you did it! Explain the bearings and different bearing numbers. Are they for Commando engines?