[Ken Smith]

I have seen many an Endpin unit socket shimmed with anything from wood to cork to sandpaper to make it fit better. The angle of the hole may be just fine. Your problem might be the difference between the taper of the hole and the unit itself. The string tension will naturally pull it forward and make it appear to be at an angle. I would guess that a slight re-fit/shim of the socket or bore itself would be the best way to go but I am just guessing blind. Pictures maybe? We are shooting in the dark here.