My brother in law made one. Has since since traded it off but it was neat. You would load about three 8’ -9’ logs on a slightly elevated rack, bottom log sat in a trough. There was a 8-10’ hydraulic ram that would push the log out of the trough as far as you wanted (typically 1-2’) and then a hydraulic 3’ chainsaw blade would cut it off and fall into a lower trough, then a second ram would push the fresh cut 1-2’ piece through a 5 way splitter. The 8-10’ cylinder is the most expensive part, but if you can find an old knuckle boom to disassembly… I wish I still had the video of it operating.
That’s it. Honda motor on ours and it splits a couple cords a year.
We leave it at our range where we cut wood. Last year it flooded. I got there late and I had to chain the splitter to the bucket of the excavator to lift and carry it out of the waist deep water. Changed fluids and fuel and it fired right up and ran fine.