(...) I'm guessing they didn't want to use lt grey because they don't think kids can easily distinguish pins and axle pins. "Standard" colour of frictionless pins is lt grey. ROSCO (18 years ago, 18-May-07, to lugnet.technic, lugnet.lego, FTX)
(...) Also, in the distant past TLC has actually produced the non friction variety of axle pin in black (I own a few myself). Although that probably doesn't matter to TLC :) (18 years ago, 18-May-07, to lugnet.technic, lugnet.lego)
