Originally Posted by
fietsbob
....the steerer tube needs to be square across the ends and just whacking it off with a hacksaw is rather difficult to cut straight with, freehand ..
Well, I certainly don't recommend doing the cut freehand but a radiator clamp tightened over the steerer will provide a very clear edge as an accurate cutting guide.
And, further, if you cut the steerer long enough to require a spacer above the stem, the top of the spacer, not the steerer, provides the surface that the top cap presses against for headset adjustment. So, the steerer being cut at
exactly 90° is not a big issue.