You definitely do not want to waste your time on a tubing cutter to cut the curved section of drop bars.
They use a pair of broad rollers as guides which first of all won't track on curves, and secondly, as they bridge across the inside of the curve will jam the cutter into the outside because the effective diameter of the bar will have changed. Not to mentioned that curved bar sections tend to be ovalized anyway.
You cut handlebars with a hacksaw. If you have zero hand skill you can put a hose clamp on the good side as a safety, but IMO anybody that can't make a decent cut with a hacksaw probably shouldn't be working on bikes in the first place.
Save the tube cutter for plumbing.
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