I have a 3" die and it needs close to 11 ton pressure to give the 3,500 psi minimum pressure recommended according to a chart that someone posted probably a few hundred or more posts back. I have the Harbor Freight frame that comes with a 12 ton jack, so I am sure it was only rated for that. The 12 ton jack was bending the lower support rails so I had to replace them with much sturdier rectangular steel. My 12 ton jack shot craps so I got a 20 ton to replace it thinking that I could just stop cranking the jack when I thought it had enough. But, you know how it is. I just crank it down to where I can barely manage to pull the handle down and when the press frame is starting to complain.
I have always had a flat 1/4" steel plate placed on top of the two lower support rail base plates so I have had no problems with them breaking. I do have a bit of an upward bulge in the top support beams. I think the Harbor Freight 12 ton press set up was just barely capable of 12 ton as it comes. With my improvements, it is certainly barely capable of handling 20 tons, but so far it is holding. I did notice that the two cross adjustment support rods were starting to bend, so I will have to get some harder adjustment support rods or give up on the under sized press and get a proper size.
I just pressed another 1 1/2 lb. batch of TP today with some added TP fines left over from my last batch. I am going to do a much more meticulous measurement of the density after I have it dried, ground, and screened. A measurement just for my own knowledge if nothing else. But whatever it ends up being is what it will be, but whatever true density it is, it has been making very fine powder.
I charred three rolls of TP this time in my large pressure pan, on my fish fryer burner, which has a fine tuning gas flow adjustment for managing the heat. I have a baffle in the bottom of the pan to keep the TP up off the bottom and I have a round weld wire cage that I made to keep the TP from touching the sides of the pan. A temperature gauge placed down into the center of the pressure release stem in the lid t so I can keep a very close eye on the internal temperature. This batch I made sure that the temperature never got above 550 F. My first batch got up to 600 F and I charred it a little longer than one hour. I think it was a slight bit over charred.
One hour of cook time for this batch gave me some really nice dark golden brown colored charred TP. It was still smoking just a bit when I took it off the heat. Just 30 minutes in the mill and it was air float. I think this batch will be very energetic.