Corinth portable sawmill- “Sawmobile”

[Ron Wenrich]

I had a guy that had taught hydraulics doing mill maintenance for me.  Before that, I would go to a hydraulic shop to pick their brain.  I got lots of good info and they usually set me up with what I needed.  Farm implement shops are often decent in their hydraulic knowledge and sometimes have some used stuff.  

Moodnacreek is correct about how it works.  I think what you want is a motor spool valve.  That allows the hydraulic to go to tank when not in use and that allows it to float.