Had a go making a cone pattern in paper just to ensure that my numbers are correct before I commit to anything in steel. It seems to work well.
This tool from Lidl makes a great set of large dividers for describing arcs. I bought it years ago and it finally came in handy today after I wiped the dust off. The points are usually stored safely away in the cut out that is showing in the lower arm of the tool. I doubt the points are hardened but I should be able to get a scribe mark on the stainless with them. The radius of the arc needed to create the cone at the large end is over 800mm so a small set of dividers won’t cut it. That's a 60 cm+ steel rule in the picture for scale.
This tool from Lidl makes a great set of large dividers for describing arcs. I bought it years ago and it finally came in handy today after I wiped the dust off. The points are usually stored safely away in the cut out that is showing in the lower arm of the tool. I doubt the points are hardened but I should be able to get a scribe mark on the stainless with them. The radius of the arc needed to create the cone at the large end is over 800mm so a small set of dividers won’t cut it. That's a 60 cm+ steel rule in the picture for scale.