I haven't had to touch my spindles yet since my IS 3200 is still new but when I saw the top of the spindle I recognized it as having two threaded holes which in the steel mill I worked as a millwright were referred to a "Jacking Bolts" . Like the other guy said, remove the two and screw them into the other holes and tighten them a little at a time to keep even pressure on them. What it is doing is breaking a tapered fit. They all work the same. Don't break them off.