not the best idea because you'll dull out the tubing cutter real fast that way.
also the cutter blade maybe just a little harder than the punch, so it could score the punch enough to where it changes the shape of it and or weakens it.
but, heck, they are only $10, when you need another one, let me know!
i've used a steel drill rod as a mandril, attached one end to my electric drill, then went at it with a tubing cutter. for $10, you can get a long drill rod to make 5 or 10 mandrills.
dan