I tried using a very large C-clamp with a cheater bar. Wasn't enough. I had to buy a 6 ton press. There wasn't much room so I had to hack off about an inch of the shaft. A full size press would be much better. With the 6 ton press I just gave it all she had waited a few minutes then gave it another pump. You're shooting for 3000psi. A small mould like the one you just purchased can get away with less pressure.