Re: how to make a cone out of a cylinder
The only one of these splitters I've ever seen used was marginal at best unless the wood was straight grained, easy splitting, like fir or cedar.
The owner had built this machine and was still trying to get it where it worked well. He had added a truck transmission ahead of the cone so he could reverse the direction when things got jammed up. Without this feature he said he often had to chop the piece of wood off the cone when it would start slipping.
Way easier to build a hydraulic splitter. More expensive but it works.
A gun and a parachute are much the same. When you need one nothing else will really suffice.