I just finished up my 5 1/4 about 45 minutes ago. It came out better than I hoped it would!
There were a couple of scratches in the sole where the previous owner must have hit a nail. They are not horrible and do not affect the usability of it, but they were a little deeper than I cared to go.
I figure I have just shy of 20 hours in it getting it cleaned up and tuned. Straightening the iron was the worst. I have over 6 hours just getting it straight before I could even start sharpening it. But once I got it square and got the angle back to 25 degrees, sharpening it was a breeze. I took the primary angle up to 4000 grit then stropped it. I put a heavy secondary angle on it by hand somewhere around 27 or 28 degrees. That I took up to 16000 grit before stropping.
I intentionally chose the piece of black walnut in the picture to test it because the grain goes every which way. It cuts like butter! Even though it is a Jack plane, I set the frog up as a smoothing plane just to see how thin I could get the shaving. I got it to consistently cut below 1/1000 of an inch. I could unroll the walnut shaving and still read a pencil mark through it!
The other thing I learned... I initially thought the Cap Iron may not have been original, but once I cleaned all the crap from the inside if it, I discovered the casting was dated 26-3. Thus, it was cast in the 3rd quarter of 1926. So I am thinking it is original.
The only thing I did not clean as well as I would have liked was the top of the Iron. Once I discovered the Stanley stamping on it, I did not want to take a chance on having that fade. So I just went over that lightly with 400 grit and called it good. If I get bored, I might try some steel wool on it, but I also kind of like the black marks on it.