I don't know what spring anchor is either but we will both learn from steve-H. I should have said "because you were unable to bob and mark". Not your fault. Straighten your spindles and measure each side. NOW use a plumb bob to mark each side of frame, then use bob again on each side to align center of axle tube.

Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn