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GENERAL CHEESE MAKING BOARDS (Specific Cheese Making in Boards above) => EQUIPMENT - Forming Cheese => Topic started by: gstone on November 01, 2011, 07:35:57 PM
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So after perusing the numerous threads here and googling images of old presses, I think I've settled on the design below.
It's a slightly modified version of this press (http://hines.blogspot.com/2010/06/biomass-fuel-briquette-presses-large.html), designed for making briquettes out of waste material. After watching the video and seeing how much force it generates (watch the 2"x6" lumber bend), I figured it would do the job on cheese. Pressure can be adjusted both by altering weight on the press arm and by moving the cheese to the right or left.
Any thoughts appreciated!
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Just guessing the dimensions of the press would give you a MA of 10 (left side of bottom lever) to 50 (right side). So hanging 20 lbs on the arm would give a pressing weight of 200 lbs to 1000 lbs. With a 4 inch mold 16 to 80 PSI. That is a lot!!
To keep the top of the cheese level with the bottom in the mold you will need a plunger that moves along the bottom lever and is kept vertical. Also check to see if you have enough vertical movement so you won;t have to reset in the middle of the night.
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Thanks smolt1. I left the plunger off to clarify the design. I'm thinking it's going to be similar to the one in your press, and there will be a series of holes placed horizontally along the bottom lever.
There will also be a drip pan with a drain to catch the whey.
This is about 2.5 feet wide, made from 2x4s. If it works out, I'd like to make one out of birch, with a copper drip pan.
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Okay, so now I'm trying to calculate the final dimensions of this thing and I'd like to factor in the mechanical advantage with the spacing of my holes, but I'm at a loss as to how to calculate it (math is not my strong suit). I know that I have two class two levers and that the "load" of the upper one, by way of the linkage, becomes the effort of the second, but I'm not finding a set of equations that matches up with this configuration. Units shown are hypothetical.
Here's the press in a leverage diagram. Any tips?
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Using the notation in your diagram:
F1 = W x (A+B)/A
F2 = F1 x (C+D)/D = W x (A+B) x (C+D) / (A x D)
Using your sample numbers:
F1 = W x (2 + 18)/2 =10W
F2 = F1 x (6 + 4)/4 = 2.5 x F1 = 25 x W
Hope this helps
Pete
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Now you have the mechanical advantage ,and the press design minimizes the friction compared to a dutch style press ( so it should be quite accurate), but I would change the copper to stainless ( copper reacts with acid ) .
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Remember that a MA of 50 means a distance decrease of 1/50th. In other words the weight on the end would have to travel downward 25 inches just to get the plunger to move down 1/2 inch.
I built one of these but got so frustrated with the travel issue that I went back to a single lever. I am sure it will work but it just means a lot of tinkering to determine if you actually have enough play at the plunger end to make it work. It would be great if you could begin with a single until the curds are fairly compressed and then switch to the double lever for the final pressing. Just a thought. Great graphics by the way. Good luck.
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@FarmerJD: Actually, the travel varies with how much to the right or left you place your cheese. That's what the horizontal series of holes are for. There is much more travel to the left side of the press. The vertical series on the plunger allows me to adjust the depth, so that as the curds compact, I can lower the plunger. Or, simply add another follower which is even easier.
I corresponded with the inventor of the briquette press and he was so pleased with my re-purposing of his design that he shared his spreadsheet with me, making adjustments for where I changed proportions. Depending on horizontal placement and the weight used on the arm, with a 4" hoop I can get:
2.5 lbs: 3psi to 10psi
5 lbs: 6psi to 20psi
10 lbs:12psi to 40psi
15 lbs: 18psi to 60psi
Obviously the larger the hoop, the fewer psi I get, but the range is still from 2.70psi to 27psi with the same weights. Using more weight can get it up to 60psi.
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The travel varies because the MA is varying as you move from right to left. I just picked an MA of 50 as the extreme example.
I also added holes to my plunger every 1/2" which helps but I still ran into the same problem because the short distance that the arm can move reduced by a factor of 50 (or even an MA of 25) is still less than the distance between the holes. Your setup is a little better at managing that since you also have the horizontal holes but I would imagine that you may have issues when you actually start using it. The way that cheesemaker's dealt with this in the old days was to add a threaded rod and wheel to the double levered press to keep the pressure up. Here (http://www.flickr.com/photos/slim_cop/5635247054/#) is a pic and here (http://www.google.com/imgres?hl=en&sa=X&rlz=1C1CHFX_enUS450US451&biw=1280&bih=653&tbm=isch&prmd=imvnsfd&tbnid=YxsZCtadL4OCDM:&imgrefurl=http://www.salvo.co.uk/derbyshire/garden/forsale.html%3Fkey%3Dblack%2520cast%2520iron%2520bath&docid=QUXmWft7QpAf9M&imgurl=http://www.salvo.co.uk/images/userimgs/6446/cheese-press_42138_1.jpg&w=675&h=900&ei=rTjDTuW3II2DtgeryYTADQ&zoom=1&iact=hc&vpx=854&vpy=124&dur=36&hovh=259&hovw=194&tx=100&ty=130&sig=118040835177438302784&page=1&tbnh=149&tbnw=113&start=0&ndsp=20&ved=1t:429,r:5,s:0).
No criticism here. I just wasn't sure if you had considered it so I thought I would mention it. Good luck.
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Well, I finally got this thing built. It's not complete yet, still have to add the plunger and feet, but it's entirely functional and of course I couldn't wait to try it out. My first pressed cheese was a gouda, which I'll have some comments and questions on elsewhere.
The press works brilliantly! Most of the needed variation in pressure can be had by simply moving the hoop from the left to the right. With ten lbs of weight on the lever, the pressure at the far right could easily damage a hand. With a simple downward pull, by hand, you could crush a coconut.
I have no worries that this will be just fine for my upcoming cheddars!
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That is a beauty. Looks like you can easily press a 10 inch diameter cheddar. I'm curious, what is the pressing weight on the left side and on the right side with no weights on the lever arm.
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Thanks. Empty, it's roughly .84 psi to 4.22 psi.
With 5lbs it's 2.11 psi to 10.54 psi. With 10 lbs, it's 6.32 to 21.08.
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On what size mold?
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Six inch.
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I'm sorry to dig up an old thread, but I'm planning on building a press, and this is the exact design I want to use!
NW Fromager, if you're still around, could you tell me the dimensions you came up with for this press?
Thanks!
EDIT: Actually I came across this one: http://cheeseforum.org/forum/index.php/topic,14493.msg122479.html#msg122479 (http://cheeseforum.org/forum/index.php/topic,14493.msg122479.html#msg122479) and I think I'd rather build it.
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I'm sorry to dig up an old thread, but I'm planning on building a press, and this is the exact design I want to use!
NW Fromager, if you're still around, could you tell me the dimensions you came up with for this press?
Thanks!
EDIT: Actually I came across this one: [url]http://cheeseforum.org/forum/index.php/topic,14493.msg122479.html#msg122479[/url] ([url]http://cheeseforum.org/forum/index.php/topic,14493.msg122479.html#msg122479[/url]) and I think I'd rather build it.
I don't mean to hijack this thread I just wanted to respond to this comment
That's my press that I built using plans provided by AwakePHD. If you read the entire thread you will see his original design based on antique metal presses. I didn't have the ability to make a custom metal down shaft so he provided the plans for an all wood version. I believe they are in thread as well. I made mine from pine as a mock up and was able to achieve almost 700 pounds of force on the down rod with a 50 pound weight on the end (50 x 14(multiplier) = 700 lbs). It should be made from hardwood such as maple or oak and in theory may be able to generate up to 1000 lbs of force because of the compounding feature.
I think the press in this thread is a bit easier to build and should get great results nonetheless.
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I realize this thread is very old - I've been away from the forum for a year or so, and have just been back in the last month or two, so I missed a bunch of threads. I happened to see this, and as it is a topic of interest to me, wanted to put in a comment. (Also I see that Chris referenced me, so naturally I MUST need to comment, right? :))
I love, love, love the elegant simplicity of the design referred to at the beginning of this thread. It is such a dead-simple design, so easy to build ... but it does suffer from one flaw, a flaw that for me was a fatal flaw.
Even though it is possible to adjust the MA, even at the lowest MA the range of movement at the ram is severely limited. This will not only make it need frequent adjustment in the early stages of pressing, when the cheese can shrink quite a bit; it will also make it difficult even to get the mold under the ram. The result is going to be a lot of adjusting, fiddling, adding shims to the follower, etc.
I have thought long and hard about whether it would be possible to modify the design to include a moveable pivot point between the upper and lower levels - this would allow lower overall MA, which in principle translates to greater range of movement - but still the stacked design sets a hard limit on the range of movement. One could greatly extend the distance between the upper and lower levers to attempt to increase the range, but still there will be some limits, and you begin to lose the elegant simplicity of the design. I keep pondering this from time to time, because I do so love the ease of building this, but thus far, I haven't come up with a practical solution. :(