Reeving a double pulley for cheese press?

[Andrew Marshallsay]

The tackle shown in the photo is actually 4:1. There are four sections of line falling from the lever with the same tension on each, hence 4:1. Again, that is the theoretical ratio, not taking losses due to friction into account.
As for fixing, rather than welding you could consider self-tacking screws or pop-rivets.

[Boofer]

It would seem like this discourse is wending its way along a similar path I set for myself when building my press.

Most cheeses don't require much pressing power. Most, IMHO, would encounter under 5 psi. Just sayin'....

-Boofer-

[JeffHamm]

I agree.  I just presss with stacking weights and press all my cheeses with 2.5 PSI or less and I get good rinds even on my cheddar types.  Pressing in the pot to keep the curds warm is easier, and more effective, than upping the pressure in my view.  A decent press that lets you get to 5 or 6 PSI will get you pretty far.

[qdog1955]

  Correct me if I'm wrong---I'm looking for 5 PSI on an 8 in. mold---I would need approximately 250 lbs.----my press only has a 3 to 1 mechanical advantage-----that would require about 80 lbs. of weight------that would be 10 one gallon bottles----I think I'd rather use the pulleys and hang a couple bottles.
   Having said that, I think you are all correct, I seem to have had better results with less psi, especially with my smaller molds. But I would like to try some Alpine type cheeses and my understanding is I will need more Psi with those types. Am I mistaken on that?

Qdog

[John@PC]

A very informative thread indeed  . On my latest press design I decided to "build in" the tackle (kind of like you did RawPrawn on your bottom pulley).  My earlier version of this had a double upright and a single arm but by going to a double arm it allowed "space" to put in a dual pulley and it also gave a better pivot for the pressing arm.   I put the "press" pivot point halfway between the upright pivot and the end.  I did a quick check with a weighing scale and it seems to be about a 6:1 advantage including friction, but I probably need to re-check.  Pulleys were made of HDPE spacers along with a large dia. SS washer and a couple of HDPE washers.

[Andrew Marshallsay]

  --I'm looking for 5 PSI on an 8 in. mold---I would need approximately 250 lbs.----my press only has a 3 to 1 mechanical advantage-----that would require about 80 lbs. of weight--
Qdog

Those numbers look about right. Can I assume that the 3:1 mechanical advantage is from the lever alone, without a tackle? If so, a 4:1 tackle will give you a 12:1 MA overall and you would only need about 21 lbs to give you the 5 PSI.
When you do set it up, you might like to check the actual force with bathroom scales or something similar.

[qdog1955]

 Wow, Andrew, I messed that one up. The 3 to 1  is just the arm and I was thinking that the added double (4-1) would give me a 7-1---so your saying it would actually be 12-1 ? I'm assuming, 3 times the four?
    This is why I'm not a Physicist.
  I did check the 3-1 on a scale---and that was right on.

Thanks for the help.
Qdog

[Andrew Marshallsay]

--so your saying it would actually be 12-1 ? I'm assuming, 3 times the four?
   

Exactly right. Happy pressing!