Since it's manual I'm sure the size of log is limited by your ability to lift....so please imagine a retirement age 5'5" white collar worker @ 155 lbs muscling a 24" x 36"+ oak log. Discuss. :D I like the Timberwolf P1 unit, and I'm THINKING I'll be splitting a lot standing up as I'll be doing a lot of smaller splits. My concern is getting the larger logs on the unit with the manual loader.....thinking too much here? I've used both CHEAP (inadequate) horizontal unit and typical vertical unit. Vertical wasn't nice to my back - so I'm thinking the Timberwolf with manual loader to not break my back...but I'll be stuck being unable to mess with the larger trunks. Guess if they are TOO large I can half them with my saw....more work, just different kind.