I hear people saying hold the wood with your hand. I can personally say, thats not always a good idea. As soon as the wood and wedge engage, my hands come back as far as my body. I might reach out and grab a piece that is ready to fall away, but I wont let my hands ride on the wood or be near it any longer.
I had a piece on there that was a lil tough and I could hear the machine bearing down and workin hard. The piece of wood suddenly popped and a chunk came flying off. Bent my thumb over backwards to the back of my hand and broke the lower thumb bone. It has made for a tough fall to get the rest of my wood done.
Just be careful no matter how you handle it.
Dang forgot any tips! If I could build one, I would think of the whole process and build the splitter around that. I have used several splitters now and looked at a bunch, and all have something unique that makes them work well or not. I'd have the trailer hitch in the front. You can leave a truck or quad hooked up to it for stability if you want. The wood would be pushed towards the back. When you get a pile and are still working, you can pull the splitter forward and continue working without having to pick up the pile. The engine should be away from where the split wood will be, so that pieces do not fall off and break things off. The filter and all hoses need to be postioned to that no wood can contact them. I 've busted 2 hoses and dented a filter with wood tossed or falling around. A log lift is nice, with a large enough cradle to hold a piece of wood bigger than what you think you will ever split. A work cradle to hold the piece you are splitting in place so it does not roll off if you want to keep your hands clear. A table on both sides of the splitting zone to work with on pieces that need to be fed through several times. Bending over to pick up pieces multiple times is a big slow down. Make the table out of pipes or somehow slotted, so that debris falls through and out of your way. The auto return is nice, the auto forward is bad idea as stated above. I'd build it high enough so I am not bending over all the time to work. Larger tires are not that much more than the cheapie ones, and make the end of the day that much better. Trailer lights, with protected lenses and wiring. Eventually your gonna want to go somewhere and its better to have it there than wishing it was. Cup holder for ice water? A sign that says "I cant hear you" when people walk up and try and have a conversation with you? Ahh you could do whatever you want if your gonna build it yourself.