Trying to freehand a spiral on a hot bar was my worst idea yet.
In my experience, when you try to twist steel by eye, it never comes out even. I was making a fireplace poker and wanted a fancy spiral handle. I heated the bar and started turning, but one section cooled faster than the rest. The twist kinked and left a weak spot that cracked later. Your mileage may vary, but take this with a grain of salt: if you're not using a jig or marks, you're asking for trouble. Now I always scribe lines before twisting, no matter how simple it seems. It might add time, but it saves the piece from becoming scrap.
Learned that the hard way when my spiral came out all wobbly. I started marking the bar with chalk before heating it up. The lines give you a guide to keep the twist even from end to end.
Setting up guides before diving in is a common trick for avoiding mistakes. It works in things like woodworking or even planning my week on a calendar. That prep work usually saves time fixing errors down the road.