by NWade » Mon May 01, 2017 11:47 am
All -
Just to put a bow on this:
About a month after I RMA'ed the prop hub (with crankshaft still attached), I got my crankshaft & prop-hub back. Sonex Aircraft's machinist (subcontractor) had a meeting with Sonex, and took my crank/hub back to be worked on. It was re-machined and then shipped back to me. Although Sonex assured me they measured the part before it was returned to me, you know I grabbed my dial indicator the moment I pulled it out of the box!
The good news is that the hub now runs true to within 0.001" during rotation, and the face of the hub is also perpendicular to the crank. The "bad" news is that the prop hubs are normally covered with an anti-corrosion plating (Zinc, I believe) after their initial manufacturing. However, the re-machining removed some of the coating. So my prop hub was shipped back to me coated in silver paint, to protect the steel.
If I had my druthers, I would have preferred a new prop hub that has the standard coating; but that would have involved pressing the hub off of the crankshaft and then pressing a new hub on - thus risking damage to the crank itself. So while the solution provided to me isn't perfect, it was the most-straightforward and lowest-risk option. Sonex communicated with me several times throughout the process - keeping me apprised of the situation, and assuring me that the issues has been addressed (for example, performing their own measurements on the re-machined parts).
I aim to have the engine assembled by the end of the week, and am looking forward to a (hopefully) smooth run from here on!
--Noel