@LORENZOJOSE I was laying out flutes on a turned column for a longcase / grandfather clock. I thought this would be ideal, but in the end found it wasn’t suitable for me. Instead, I ended up dividing the circumference up at the top of the column, again at the bottom, and then using a manilla folder to connect the dots. The card stock flexed to follow the curves of the column. I put a Bessey clamp (F clamp) in the vise and then held the column with that. By fiddling around with the height of the clamp, I could have the the card stock be supported by the bench so that I could focus on holding the working edge on the layout marks. Because of this, it turned out best to leave the folder wide rather than cutting a ruler-like strip.
There were 8 flutes. The standard trick of dividing by walking dividers around I found unsuitable. It is too easy to mess up, too fussy, and can leave prick marks from the trials. Also, we care more about it looking right than being right. So, I focused on getting 4 divisions first, aligned with the 4 faces of the column base and top, then dividing those in half and adjusting by eye to look right.
It’s really easy to end up with the flutes having a bit of barber pole swirl to them! I didn’t avoid this completely and I think it came in during the carving, not the layout.
Anyway, the ultrafine chalk line is sitting in the toolbox. It will be useful for other things.