Any bog standard pipe cutter will do the job, just take it nice and easy, and use WD40 on it.
I have a waaaaaay old one that I inherited form my dad, must be 25 years old at least. Used it recently to cut both steel and alu steerers no problem.
+1 for measure twice (or even thrice) cut once……..don't do what I did a few years back, measured the headtube and the headset, and then the spacers, and then the stem. Did that all twice, added it up, then cut the steerer. Hmmmmmmm, that's funny, it's much too long I thought……….I'd only gone and measured the whole length of the headset, not taking off the part that sits in the headtube. Doh 😆 That learned me.