Relentless overhead blows with a 1.360 kg block splitter turn a big lump of wood into middlings and kindlings, either quickly and crisply or horribly slowly, depending mostly on whether the grain is lined up nicely.
But that always assumes you can make the thing stand up to be hit.
The target lump
of wood approximates to a cuboid, a cylinder or a semi-cylinder, and the long faces are long in the direction that was vertical when the wood was part of a tree. Therefore, to be in with a chance of catching the grain, you have to stand it on one of its small faces, which would be fine if its vertical cross-sections were rectangles.
They are trapezia.
Therefore the target lumps lean and often topple.
If you're following this closely, mind your head.
The solution is a type of chopping block. Its rough (i.e., high-friction) wooden upper surface has three planes. Each of these planes is wide enough to carry the short face of a target lump.
They sit at 0, 15 and 30 degrees from the horizontal. This is because 7.5 degrees of lean are rarely enough to carry the centre of gravity to the unsupported side of the fulcrum. Unless the original mechanical saw, that made the lump, was swung by a gremlin with malice aforethought, the basic lean will not exceed 37.5 degrees.
To this point, the idea is far too simple. Therefore let it be turned around a vertical spindle and then locked in place with locking pins. The locking action must pari passu retract the bearings on which the block rotates around the spindle, to protect them from damage from the shock of those relentless overhead blows.