Screw-ram Compound Press Design Modifications...

[bliorg]

Hi all -

Christmas is coming.  My wife is a budding cheesemaker, and I want to build her a press.  I'm out to build a variant on awakephd's screw-based compound press (https://cheeseforum.org/forum/index.php/topic,14493.0.html) and need to solicit opinions (I went to IM Andy directly but he seems to not have been active since March).  I'm neither a machinist, nor have access to one, so the pivoting nut that is the critical element of Andy's design is out of reach.  There is, however, a threaded clevis rod end (https://www.mcmaster.com/1583K19/) that would allow the screw to pivot.  This would require an appropriately sized threaded rod, sizing the structure correctly, and limiting the throw of the screw to about 3" (based on the sizes I'm considering) due to the limit set by the pin.  My question for those of you that have adjustable compound presses such as this (or the all wood variant) is how much throw is actually needed in practice?  Is the travel of the lever arm, plus the ~3" of adjustment in the clevis rod end setup enough to press, say, a decent cheddar?

If this setup isn't feasible, I'm more than happy to make the all wood design.  But anything worth making is worth overmaking, and the engineering in Andy's design is just elegant.

Thanks for your thoughts.
Scott

[pickles]

My press is extremely simple but effective. The process is very similar however sophisticated the device.
In general when you press a cheese the process is performed in stages.
To begin, a lowish pressure is exerted for a relatively short period of time, the pressure is then stepped up and held for a longer time. This could all take place over several hours with increases at each stage.
The majority of the pressing takes place at the first stage, the overall effect of the press gradually decreasing with each progressive step.
I built a simple lever press that delivers about 7kg [15lb] for 15 or so minutes at the first stage. The change in volume of the cheese is relatively minor and there is no where near a change in height of the follower of anything like three inches, but this is when the largest change takes place.
After the first stage with my press I increase the pressure to around 20kg for 6 hours, turn the cheese over and press again for another 6 hours. At no stage is there any large change in the height of the follower.

So I would say that if you have the capacity to change follower height by three inches that should be ample allowance for, dare I say, all circumstances.

I am a relatively new cheesemaker and am happy to defer to any who can cover or explain this better than I.

I could go into more detail on my press, but I have answered your question as best I am able.

Here is a rough sketch of my press set up:

[Bantams]

As stated above, a cheese will only shrink by a small amount (1-2" depending on cheese type and total height). The biggest issue with a limited range is that depending on your batch size or cheese type, you will have varying amounts of curd to put in your mold each time.  Sometimes your wheels will be 3" tall, sometimes 6". You'll need a press that can handle a moderate range of sizes.
At least I think that's what you were asking about! (Sorry if I'm wrong)

[pickles]

As stated above, a cheese will only shrink by a small amount (1-2" depending on cheese type and total height). The biggest issue with a limited range is that depending on your batch size or cheese type, you will have varying amounts of curd to put in your mold each time.  Sometimes your wheels will be 3" tall, sometimes 6". You'll need a press that can handle a moderate range of sizes.
At least I think that's what you were asking about! (Sorry if I'm wrong)

Bantams has a point there that I hadn't covered. As he says you need a press that can accomodate different sized cheese forms. For my press I would adjust by using a different sized block but in the sophisticated press you need a solution that takes into account your equipment.
I think Bantams has given you the better answer.

[bliorg]

Thanks, both of you.  Points well taken.  What I would suggest as a possible, though somewhat clumsy solution, is that the block in your drawing can stay the same dimensions, but the table under the mold can change height.  I could set the height of the ram such that different sized molds can be blocked up from below to work within the capacity of the press.  That's essentially how a wine basket press works (kinda, in reverse).

I think I'm going to need to do some math to figure out angles and dimensions...

[pickles]

Thanks, both of you.  Points well taken.  What I would suggest as a possible, though somewhat clumsy solution, is that the block in your drawing can stay the same dimensions, but the table under the mold can change height.  I could set the height of the ram such that different sized molds can be blocked up from below to work within the capacity of the press.  That's essentially how a wine basket press works (kinda, in reverse).

I think I'm going to need to do some math to figure out angles and dimensions...

Working out what the maximum required mould height is likely to be then creating spacers to build up from below sounds like a good way to go, in my case at least.

Its always a good idea to rough out the idea before you start. That press you intend to make looks very smart, bilorg.