Size wise 3BA is close, but the BA thread is way too fine,
nothing on my metric thread gauge was an exact match, 0.5 & 0.6 were close but the angle isn't quite right, which is why I guess 1/8 unf.
Edit; I stand corrected under a magnifying glass it is indeed 4BA, but the thread is still too fine to fit my Supersport
Last edited by angrybear; 09-03-2021 at 10:23 AM.