I'd suggest something like this, where the force increases as the pieces reach the flat position- basically, the principal used in a pair of vice-grips.
Without knowing the force or the travel involved, it'll be hard to get any specifics without just trying something out.

You say no jacks, but a high-lift/ farm jack would be an obvious choice. I've got an old hydraulic jack in the garage that I would use. An old bumper jack would work, too.

Got any idea of how much force needs to be generated and what amount of stroke at this force? Is the point of the press to de-water the slurry in a mold? It seems like an acme threaded rod would provide good compression force, why don't you want a jack? You might learn something by researching blacksmith fly presses - this is a manually powered press that converts rotary motion into force. Have you prototyped your logs? How long do they take to dry?

Doesn't seem like "maximum pressing power" is necessary.

The commercially available thing looks to make do with entirely "ordinary pressing power".

https://www.amazon.co.uk/dp/B0B88FWWK6/ref=sspa_mw...

The design of the press would be effort and time saving if the product could be formed in one pull of a lever, the problem with a hydraulic jack is pumping the thing up each time, which makes producing these on a large scale very time consuming .

A fly press is an option but big ones cost a lot of money and weight hundreds of KG's.

waterworks178,

Read MIL‑STD‑1472, all about human factors. This will tell you how much force your operator can exert on your lever?

How much force will it take to compress your logs, and how much distance must be travelled? Now, you can work out how much leverage you need to compress everything, and how much lever movement is required. There are lots of leverage devices out there.

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JHG

Quote (waterworks178)

The design of the press would be effort and time saving if the product could be formed in one pull of a lever, the problem with a hydraulic jack is pumping the thing up each time, which makes producing these on a large scale very time consuming .

Unrealistic expectations - obtain the right equipment for the production rate you want. Variations in operator effort and product slurry will result in uneven dryness of the product. A large scale operation will have a lot of logs drying. You need to quantify more about this process to have a better chance at success.

You can't have both long stroke and high force, your lever will trade one for the other.
So in order to get a high force (higher than just pushing on it) you will need many more strokes.

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P.E. Metallurgy, consulting work welcomed

I found this solution to what i need, if I beef up the design , remove the jack and fit a longer manual lever it should press out a good solid brick of fuel at a good rate.



https://youtu.be/c_UuVV7fhMc?si=93vFj415D1JNB_VS