Crack in Cummins Spinner

[Bavafa]

Just a word of caution to check your Cummins Spinner screw holes closes to the blade openings. My beautifully chromed spinner has a hairline crack at the three of the four holes that is next to the blade. This was installed according to the instructions which has six screw on each side, 12 total and it is my second spinner from Cummins. The first one did not have a good fit with the front plate so he did send me a second one. I had the first one installed and roughly 40-50 hours on it (no crack but not chromed either). The second one has about 75 hours on it and was chromed so not sure if the process of chroming causes this or just softer aluminum.
Even though I have the first spinner, I am giving up on the aluminum one and just ordered a fiberglass from VANs. Not worth the risk considering there has been other reports of cracks.

[gmcjetpilot]

Originally Posted by Bavafa

Not worth the risk considering there has been other reports of cracks.

Thanks for the PIREP... yep chrome can reduce fatigue life. Not sure about the chrome process changing the heat treat of the aluminum... but chrome is super hard but brittle. It bonds to base metal. Crack forms in chrome and creates a stress riser or stress concentration in base metal.... It does not take much to magnify the loads and for the crack in the chrome to grow in the base metal.

[FORANE]

After repeated cracks in BN-3 aluminum spinners and even a chunk of spinner departing the aircraft in flight, I converted to composite. No problems since.