I got a shimano hub for my front wheel and rebuilt it last November, but didn't ride much until March. Now I hear a metal on metal grating noice when riding and my best guess is that it is comming from the new hub. Doesn't happen when I just spin the wheel, only when riding and not all the time.
Took the hub apart to see what is wrong and also add more grease. When looking for damages I noticed that on one side, in the cup part, there are two metal pins. They are the two little dots at 8 o'clock on the cup. (Apologies for the image quality.) They look like how nails without heads look, except that they jut out a bit and rounded on the top.
Is this normal? Do they serve any purpose? Could they be something that was in recycled metal, assuming these are machined and not casted?
Above all, could these be causing the noise? My guess is that when the cone is pressing, the bearings can get jammed in these withoug rolling smoothly. Each pin is about 1.5mm wide and jut out about 0.5mm.
Update: Added few clear pictures.
Last time around I used white lithium grease. I took the hub apart today and on the side with the problem grease has changed to dark gray while the other side is still white. I will see if these flattern out over time and then replace the bearings. Or replace the hub altogether.