On Sunday I made a Gouda following Dave's (aka. likesspace) recipe. On this occasion I used my Extech pH100 meter for the first time. I also used my new small (450g) Kadova moulds for the first time. But the real kicker was that I got to use my newly-built Dutch press.
Following visuals from Alex and others I built my press out of 2"x8" and 2"x3" hemlock stock. I decided I wanted something fairly hefty so I used 1" square steel tubing for the lever arm and 3/4"square steel tubing for the vertical ramrod. The majority of the construction is complete but I still have a few finishing touches to add.
Using a combination of a 5-pound and a 10-pound weight, I am able to deliver 200 pounds to the pressing point. I used a scale to check the actual press weight. The most I've checked is 25 pounds on the lever arm...delivers 300 pounds. The scale only goes to 350. According to my Excel "Lever & Pulley Worksheet", I should be getting close to 400 pounds. Need to investigate a little further why my actual falls short of my calculated.
I am encouraged by the results I've experienced so far. I was using a stack of 5, 10, 10, 25, and 25 pound barbell weights to reach a maximum press weight of 75 pounds. This was unwieldy and an inconvenience using all those heavy weights. Now I use fewer actual weights combined with a little advantage to gain a much larger applied weight.
The cheese was pressed when the curds were cooled down. I put the moulds in the pot with warm whey and held them for an hour, then pressed at 4psi (15 pounds actual). It helped to form a better closed knit to the curds. You can see one of them still is a more open knit.
-Boofer-
Very nice looking press. I am impressed.
Question: What kind of PSI are you looking to achieve?
My math says that with 200lbs of downforce accross all your moulds there, you get about 8.5psi.
That is just about where you want to be in my book. Perhaps a touch more, but not much.
Press looks really nice Boof. You will be taking a big leap in your learning curve with that press.
I believe your theoretical differs from the actual because you have the fixed end of the pulley line attached near the middle of your lever. You are losing some of your mechanical advantage and would have stronger force if you moved that line out to where the block is at on the lever arm. Some blocks have a connection point for exactly that purpose. (Sailboat blocks take advantage of that ;D)
The other thing I notice is that your ram rod is not actually attached to the lever arm. I wouldn't trust that with 300 pouinds of force. :o You are probably losing some power here as well. The lever has a force vector that is pushing forward as well as down.
See what I mean about using scales to test and calibrate your press?
You get a cheese from me. A+ for making the leap.
Great pics. You really did a great job designing the press. I can tell you why your values are off but I don't want to sound negative, so please don't take it that way.
First, the MA of the arm is 4.8 not 3.8. You divide the total length by the distance to the rod. It is a common mistake to use only the extra length (in your case 38 in).
Sailor pointed out the source of the second problem; you actually have 2 connection points on your arm for the pulleys. This actually creates a complex situation where you have to figure 2 separate forces and add them together; one for the weight on the end (25 lbs X 4.8 = 120 lbs) and another for the weight applied at the second point where there is a lever mechanical advantage of about 2.5 ( a guess from the pic) and a pulley advantage of 3 (even though there are more pulleys, 1 is simply changing direction for you). This means the second force is 2.5 x 3 x 25 = 187.5 lbs. If you add you get 307.5 lbs. I figured that the distance from your pivot to the first eye bolt is 24-25 inches which would make the mech advantage at this point 2.4-2.5.
You really don't have to even figure it mathematically since you have a scale but i thought I would throw it out there.
The other question I have is about the psi generated on your cheese. I figured each mold at 4.375 inches and get an area of 15 square inches for each one. Is this right? If so, and there are 4 separate molds, then the psi would be the total wieght (300lbs) divided by the total area (60 in2) which equals 5 psi. I could be wrong about the sizes and even the math, so correct me if I am wrong on this.
Sailor mentioned the pin being a problem. You might try using a u bolt and bolting all the way through. Just a thought.
It is obvious from the pics that you are a craftsman. I wish I was more patient with the details like you and Alex. You get a cheese from me too. Thumbs way up!
I guessed at 3.75 inches diameter per mould. That is why my math came to about 8 PSI
I could be off in that guess.
Quote from: Sailor Con Queso on May 26, 2010, 07:01:08 PM
The other thing I notice is that your ram rod is not actually attached to the lever arm. I wouldn't trust that with 300 pouinds of force. :o You are probably losing some power here as well. The lever has a force vector that is pushing forward as well as down.
How do I lose power? I've tried to minimize any forward effort by having the lever push more-or-less directly downward.
See what I mean about using scales to test and calibrate your press?
You mean it's a good thing...that it helps to validate my assumptions, correct?
Thanks for the corrective advice on my pulley setup. I moved it, but I don't see any difference. Perhaps on a sailboat where the distances are greater there would be a significant change.
Quote from: FarmerJd on May 26, 2010, 09:11:37 PM
Great pics. You really did a great job designing the press. I can tell you why your values are off but I don't want to sound negative, so please don't take it that way.
No, not at all. I welcome and need all the help I can get. Never was good at physics.
First, the MA of the arm is 4.8 not 3.8. You divide the total length by the distance to the rod. It is a common mistake to use only the extra length (in your case 38 in).
What I read online says differently: "The mechanical advantage of a lever is the ratio of the length of the lever on the applied force side of the fulcrum to the length of the lever on the resistance force side of the fulcrum." Is that incorrect?
Sailor pointed out the source of the second problem; you actually have 2 connection points on your arm for the pulleys. This actually creates a complex situation where you have to figure 2 separate forces and add them together; one for the weight on the end (25 lbs X 4.8 = 120 lbs) and another for the weight applied at the second point where there is a lever mechanical advantage of about 2.5 ( a guess from the pic) and a pulley advantage of 3 (even though there are more pulleys, 1 is simply changing direction for you). This means the second force is 2.5 x 3 x 25 = 187.5 lbs. If you add you get 307.5 lbs. I figured that the distance from your pivot to the first eye bolt is 24-25 inches which would make the mech advantage at this point 2.4-2.5.
As I replied to Sailor, I moved the rope at the midpoint out to the end of the lever by the top pulley block. I saw no difference in performance. Using 25 lbs with my original configuration, I was able to deliver 300 lbs to the ramrod. You are correct: the rope at midpoint was 24 inches.
You really don't have to even figure it mathematically since you have a scale but i thought I would throw it out there.
The other question I have is about the psi generated on your cheese. I figured each mold at 4.375 inches and get an area of 15 square inches for each one. Is this right? If so, and there are 4 separate molds, then the psi would be the total wieght (300lbs) divided by the total area (60 in2) which equals 5 psi. I could be wrong about the sizes and even the math, so correct me if I am wrong on this.
I figured 15 sq in for each of the small moulds. Using a 10lb weight gave me 200 pounds on the ramrod for 3.3psi.
Sailor mentioned the pin being a problem. You might try using a u bolt and bolting all the way through. Just a thought.
I don't see what you mean with the u-bolt. Can you explain, please?
It is obvious from the pics that you are a craftsman. I wish I was more patient with the details like you and Alex. You get a cheese from me too. Thumbs way up!
No, not a craftsman at all...just trying to solve a problem.
Quote from: Wayne Harris on May 27, 2010, 12:15:57 AM
I guessed at 3.75 inches diameter per mould. That is why my math came to about 8 PSI
I could be off in that guess.
I measured mine at 4.375 inches. That gives 3.3psi using a 10lb weight.
Thanks, guys, I appreciate the feedback so I can tweak my setup and be correct.
-Boofer-
Ok several things to address:
1. When Sailor said you would lose power, I think he was referring to the fact that the piston might tend to lean more heavily on the side closest to the arm and increase friction on that side leading to a decrease in downward force. I do think this is possible. My solution of a u-bolt would not change that though. The only way to really address it would be to have a dual arm on either side of the piston. I am not sure it is necessary.
2. You quoted a statement from a website as follows: " The mechanical advantage of a lever is the ratio of the length of the lever on the applied force side of the fulcrum to the length of the lever on the resistance force side of the fulcrum. This is the MA for a 1st class lever like a seesaw. In that case, the resistance and applied force are on opposite sides of the fulcrum. In your press, they are both on the same side like a 2nd class lever; therefore the applied force is the whole length of the arm.
To prove the point, consider when the MA would be exactly one. It would be if you put the weight right where the piston is. If you worked this according to the method you were using, the MA would be zero which is impossible. (i.e. my way: 10 inches / 10 inches = 1 MA Your way 0 inches/10 inches = 0 MA)
3. Are you saying that you moved the eye bolt from the 24 inch mark to the 48 inch mark? If you did and you left the anchor point way back underneath the 24 inch point, then the pulley advantage would have been decreased because of the angle. Part of the force was pulling the arm toward the piston and not downward. If you move the bottom anchor point to the point under the 48 inch point, you will see a difference. If not, then you may be trapped in a wormhole and the laws of physics don't apply. :)
4. The u-bolt was just an idea to keep the arm from sliding off the piston. I was thinking you could drill another hole in the piston above the bolt that is there now and stick a u-bolt through these 2 holes with the arm inside the U. Kind of hard to express but a simple idea. But it would not help address Sailor's issue.
If any of this doesn't make sense, I am sure it is my fault. I just reread it a got a headache. Good luck. ;)
Good work Boofer!!!
My pulleys system is delayed, because being a cabinet maker, my pulleys "have to" be made from wood. I hadn't time to turn them on my lathe.
My English is too poor to use so many words to explain, so I made a sketch.
According to physics, W1 * L1 = W2 * L2. Kooking at the system you've built, the actual force you apply is W3, applying less pressure than from W2. Therefore the difference between the weights and the reading you make. To solve this, just cancell the fixed point of W3 and you'll be fine.
I built the lever arm of my press as a ladder, because in this way I can change the point to hang the weights and get an even bigger versatility, of course using the pulleys system.
::) I'm a little slow, but I'm catching on!
Taking the combined advice given to me today, I moved the rigging and here are my revised readings:
Using an applied weight of:
- 5 lbs ====> 157 lbs . . . a force multiplier of 31x
- 10 lbs ====> 265 lbs . . . a force multiplier of 26.5x
- 15 lbs ====> 350+ lbs . . . a force multiplier of around 23.3x (topped out the scale)
That makes me much happier! Now I need to figure out how to clean up the modifications. I'd like to be able to hook up and go when I need to press.
The strange thing is, the 1-inch square tube bends with applied force. I guess I didn't expect it to
give so much. I also need to goose the hanging weight to arrive at the final terminal applied force. The goosing ensures that the rope isn't cinched on the pulleys and that the full pressure is brought to bear, otherwise the whole system creaks and creeps, applying pressure a little at a time until it reaches its terminal point.
Farmer & Alex - You're right about the length of the lever. I knew it was a class 2, but for some reason my mind plugged in that division at the ramrod point. I stand corrected. You're right too, Farmer, this burns out brain cells. I'm toasted...but better informed now.
Farmer - I understand your u-bolt visual now. There isn't a lot of lateral play in the lever arm so I'm not too worried about it slipping off the pin in the ramrod. I will monitor it though.
Alex - I admire your ability with cabinet-making/woodworking. Your press is closer to artwork. I'm afraid I'm limited in those areas and so I have to settle for a more brute-force approach.
-Boofer-
P.S. I sleep better tonight. :) Guys, thanks for the steerage.[/list]
Hi
I was just wondering about the profiles you used: isn't it much overkill? I am currently trying to design a 2 level dutch press to build when time is available, but using some stress formulae a 50x18 mm wooden beam (.2" x .07") would be more then enough to transfer 8 Kg to 100 Kg pressure. (all horizontal beams are double)
This flat structure will be clamped in the base, I designed two parts for easy storage, but not sure it will hold...
BTW: how much travel do you need during first and later pressing?
Amnon
Boofer, replace the lever arm with a 2"x1" RHS.
Amnon, as you can see on my smaller press, the plunger is long enough and drilled, to be adjustable according to the different hoops heights.
nonius, the travel is the problem with a double levered press. I tried it and the lever has to fall a long way to produce a small movement of the piston. It basically bottoms out too quickly. It would work if the press was very tall like the ones people use to build. You need about 8 inches of travel total at the piston which translates to 32 inches of travel on the end of the arm with just a mechanical advantage of 4. As Alex said you could have multiple holes, but you still need enough travel to apply pressure and this is difficult with large mechanical advantages.
Boofer, I agree with Alex that the arm needs to be bigger. You could probably get by but to really be able to load it up you need to replace it.
As far as the total mechanical advantage, the best I can figure is 24. That is 5 (pulley advantage) times 4.8 (lever advantage) = 24. I can't see any other factors except maybe the weight of the arm itself. I think I would figure a 25 MA and just go with that. Good luck and hang in there. We are all learning with you.
Nonius, I think your design is the same thing I tried. Here is a sketch of what I tried to do.
Boof,
5 pounds of weight with 157 pounds at the plunger is going to be overkill on a lot of cheeses depending on the mold that you use. For example, I do an overnight pressing of my Stiltons (phase 1 prior to salting) at just 1 psi. In your case 157 pounds on a 6" hoop (28.27 sq inches) would be 157/28.27 = 5.55 psi. I press Goudas at just 2-3 psi. So you need to figure out a way to really back off when you need to.
What is the bare pressing weight (measured on a scale) when you have no additional weight attached?
Farmer,
I am setting up a commercial kitchen for cheesemaking and other pursuits. I could go with an air pressure system (ala Carter) but I want it to look a bit primative and old fashioned, not industrial. This is a permanent setup, so one of my thoughts is to use a third single wheel pully attached to the ceiling, so there would be plenty of room for drop.
Don't have a working drawing, however the final working line would go from the lower block to the ceiling pulley. I know that this would lose 1 leg of the mechanical advantage but I could use a triple block instead of a double. This setup would give 8 feet of drop.
Sailor, IMHO, removing the pulleys system is always an option to decrease weight/pressure.
Sailor, the only catch would be that the press might have to be attached to the floor if you are using an anchor outside the system. Not a problem but needs to be considered. In fact, you could actually put an anchor on the ground in front of the press for your last pulley and then go to the ceiling. That way you don't lose the MA you mentioned. I think I would use chain for my final leg so that you could always move up to another link and reattach to keep tension. I am sure Wayne has some chain you could borrow. :)
Alex, when you make your wooden pulleys, you may have to turn some for Sailor and I. Just to keep that old fashioned look. ;)
Quote from: Alex on May 27, 2010, 02:49:08 PM
Boofer, replace the lever arm with a 2"x1" RHS.
I don't understand why I should replace the lever arm.
Sailor - The lever arm and ramrod weighs in at 11 lbs.
Can you see anything in my calcs that would account for an actual of 157 lbs and my calculated 107 lbs?
(5 * (4*4.8) ) + 11 = 107 lbs [lbs * (pulley advantage * lever advantage) + lever&ramrod weight]
3.14 * ((7.375/2)*(7.375/2)) = 42.7 sq in [pi * mould radius squared]
107/42.7 = 2.5 psi [lbs/sq in= psi]
If I am to believe my math, I have 2.5 psi to press my Gouda with.
-Boofer-
Boofer, You wrote that the arm is bending, or may be I missunderstood you.
Farmer
QuoteAlex, when you make your wooden pulleys, you may have to turn some for Sailor and I. Just to keep that old fashioned look.
With pleasure, that's the point, old fashioned look. Tell Sailor, when he will sail to the Italian west coast, to "jump" to Haifa to collect the pulleys.
Quote from: FarmerJd on May 27, 2010, 03:13:49 PM
As far as the total mechanical advantage, the best I can figure is 24. That is 5 (pulley advantage) times 4.8 (lever advantage) = 24.
I'm a little confused (again)...you mentioned earlier that even with my quad pulley setup I was really only seeing 3 pulleys because one was only changing direction. Somehow you've given my system a pulley advantage of 5 instead of 4. That would bring it closer to explaining the disparity between calculated weight and actual weight, but how did you come by that? Please don't take this wrong. I appreciate your input.
Also, there is a slight bend to the RHS but not IMHO excessive, especially for the stresses I expect to see. If I were to really get crazy down the road and try to actually put 75 lbs on the lever (shudder!!), I would definitely need to make some heavy-duty changes to the press.
-Boofer-
The short answer is I was wrong. You can skip the next paragraph unless you are just curious about the original setup.
To figure the MA of a pulley system, you actually figure by the number of ropes/legs but some of them can be simply for changing direction so you have to evaluate it. I made a mistake the first time, because I am conditioned to look at pulley systems with the fixed point at the top and the resistance pulling down but movable. Our presses are different with the resistance pushing up and movable but the fixed point is below. I wrongly counted the first and last legs as simply redirection (really stupid; must have been late). To be honest, i looked at it again after I posted the first time and started to post again but then you moved the pulley so I just punted thinking it was a moot point. The way to figure the original setup really involves knowing the angle of the ropes because only a portion of those 3 middle legs are pulling straight down on the end of the arm. So you have to figure the first leg, middle 3 legs, and last leg separately. I didn't do that the first time. I still get numbers slightly larger than your original values (assuming a 45 degree angle) which leads me to believe you have a lot of friction in your system.
The calculation for any simple pulley system really comes down to simply this: All the ropes in a pulley system have the same tension. If they are all pulling in the same direction you simply count the legs. Of course, there are complex systems that are figured differently but your current setup is not one. It has 5 legs and all are exerting a force downward therefore the MA = 5.
QuoteCan you see anything in my calcs that would account for an actual of 157 lbs and my calculated 107 lbs?
[/size]
(5 * (4*4. ) + 11 = 107 lbs [lbs * (pulley advantage * lever advantage) + lever&ramrod weight]
3.14 * ((7.375/2)*(7.375/2)) = 42.7 sq in [pi * mould radius squared]
107/42.7 = 2.5 psi [lbs/sq in= psi]
If I am to believe my math, I have 2.5 psi to press my Gouda with.[/size]
I am not sure I understand the first line of this. How much weight is hanging on the end? If it is 10 lbs then I would calculate the predicted force on the scale this way:
5 (pulley MA) x 4.8 (lever MA) x 10 (weight attached) + 11 (lever and piston weight) = 251lbs
If you get a greater value than this, let me know. Sorry so long. Hard to know where to start and end. I hope it is helpful.
Forgive me, but am I the only one thinking "way too much math here"?
Sorry. It's an obsession. Kind of like cheese. ;D
You all have inspired me to start thinking about a new press.
My thoughts so far....
Quote from: Nitai on May 29, 2010, 04:57:24 AM
Forgive me, but am I the only one thinking "way too much math here"?
Yeah,
me!
No, actually I built the press and I'd like to just have some assurance that I'm pressing somewhat accurately. There's a decided difference between 50 lbs and 250 lbs. If I use a 5 lb weight to develop 107 lbs pressing on my cheese, I want to know what's being delivered. Short answer: it is a momentary obsession. Once it gets ironed out, then I can rest...no, that's not true...making baby swiss early in the A.M. (Using Sailor's guidance.)
Farmer - Excellent tutelage. I'm seeing this press in an entirely new light. Thank you for not letting me work this out in a vacuum. :P
Wayne - Cool graphics. 8) Does it come with any dialogue to describe what we're seeing?
-Boofer-
Hi Wayne
Force multiplier of a double lever system is high, but your design will give little travel on the plunger. What I see from your graphics your long lever can rotate only about 40 degrees till it hits the upper cross beam, resulting in ~10 degrees on the lower lever. Since the pressure point is very close to the hinge point the plunger will travel only 3% of what your pulley at end of long lever will travel.
This is why I asked before how much travel you need for pressing cheese or how much does the cheese compress. This is especially relevant overnight/ during workhours as knowbody is there to readjust, and your press is delivering all that force to its own frame, instead of on the cheese :-)
Amnon
Amnon, I realized when I was tinkering with that idea that this was the reason that the old double levered presses had a threaded rod in the middle; so that they could constantly keep the pressure on the cheese in the small window of travel. So the question is can it work effectively with a taller frame. You set up your levers in the diagram just like I tried but in my case it bottomed out and I abandoned it because I couldn't justify making it any bigger. I need to go back and study the pics we have of old double levered presses. Good discussion.
Hi Farmer
Just curious, as I still have to start my first pressed cheese...
I read Gouda and the like are first pressed with a lighter weight for 2x or 3x 1 hour, only later pressings are with more weight.
Would it work to use the long lever in the beginning with lower multiplier and enough travel for initial compression of curds. Only at last pressing using the double lever assuming cheese will not compress too much?
Would you have numbers on compression per stage/ pressure applied for e.g. your cheddars?
Amnon
I know I have mensioned this before and didn't get much of a positive reaction - but now you all seem to be thinking in the same direction so ...
I have been playing with the idea of building an almost all wood version of this beasty since late last fall - just can't work in the basement in the winter - to cold for the old bones no heat down there. I have most of the parts I need, still looking for weight ideas and I am going to use an veneer press screw for the pressure piston.
Amnon,
Most of my semihard and hard cheeses are made from 10 liters of milk in a 6" hoop. After the light and medium pressing, the curds height drops about 1-2 cm, that's all.
A problem may rise when pressing taller cheeses, and more than one, one on top of the other/s (as seen on Debi's picture). In this case a bigger height drop will need a longer travel of the plunger.
Amnon, that really is a great idea. It looks like your diagram has a possible connection for the piston on both levers. As far as the travel needed, My cheeses are normally 24 gal and I have a 10 inch hoop that is 14 inches high. I fill this hoop at least 10 - 14 inches deep each time and my final cheese is about 6-8 inches high. I have to have about 8 inches of travel therefore. I usually have to move the pin connecting the piston to the arm once during a pressing. But when I tried the double lever, I only had about 1/2 inch of travel so it would still be a challenge to make this work without a threaded piston since the holes on the piston have to be in just the right spot.
Debi, the problem with wood on a double levered system is that the arms have to be so thick and wide to handle the load that they wind up getting in the way of each other and reducing the distance they can swing. Not impossible but challenging. I believe the pic you posted gives a MA of about 20-25 where Wayne's is about 70-75, and Amnon's about 13 and Mine was about 32. (estimates based on eyeballing the pics but in the ballpark) Your pic is unique in the way the levers attach. It gives a lot of extra room for movement/travel by allowing the contact point between the levers to travel/slide up the length of the long arm. Notice that the top arm rests on top of a pin on the bottom arm and is not pinned to it. The bottom arm is also resting on a pin on the piston much like boofer's except it is on both sides. It may seem insignificant, but it allows the arm contact point to move as the cheese shrinks. As the cheese shrinks the arm drops, the connection point moves and the pressure increases slightly. I think that is an important tip to consider. Probably the best system is a wood frame with a metal mechanisim somewhat like this one except with a higher MA.
I still like sailor's ceiling pulley idea, though. :)
I realize that in my design, the plunger arm will not move far at all. In fact, I plan to have lots of holes on the plunger arm. This will allow me to re-adjust the arm as the whey expresses. In my minds eye, I envision going through about 5-10 cycles where i set the arm, let it compresse, then i have to re-adjust plunger arm, then wait..... over an over till the cheese stops compressing...
Wayne the problem I faced was that the travel on the plunger was so small that it did not leave me enough play to switch holes. You would have to have holes very close together which means having a metal plunger. I hope that makes sense.
I never had to change the plunger's position during pressing. The height's adjustment is mainly needed considering the hoop's size/height.
JDfarmer's looks like alot of weight on that poor cheese!
If your plunger is 5" from the fixed point and the weight is 30" from the plunger you get a factor of 6X your weight. By adding the pulley it is possible to double or triple that amount.
I found it was less to clean by adding "ARM" (distance from plunger to weight) than dealing with a block and tackle set up (as in JD's)
http://www.answers.com/topic/lever (http://www.answers.com/topic/lever)
Boofer,
A 1"X4" piece of oak will hold allot more weight than your tube, otherwise a really nice job on your press.
Quote from: coffee joe on June 26, 2010, 10:21:58 PM
Boofer,
A 1"X4" piece of oak will hold allot more weight than your tube, otherwise a really nice job on your press.
Thanks for that advice.
I am quite happy with the performance of my press. It does what I expected. The most I can measure with a scale is 350+ lbs using a 5 lb and a 10 lb weight coupled with the double pulleys. I can also drop back and only use two pulleys for less pressure. That flexibility will serve me well for any cheeses I anticipate making in the future. If at some time I were to move into larger moulds, I can move to my 25 lb weight which will again provide the pressing service I need.
Sailor mentioned that for a lot of cheeses the psi I can deliver would be too great. I would agree. In fact the most recent cheese I made last week was a 7.375 inch wheel of
Esrom. The most that I used to press it was 15 lbs and I didn't even use the press. I pressed it in the warm pot and gained a tighter knit thanks to Sailor's suggestion.
It's a flexible capability thing. Sometimes the press is needed...sometimes not. My recent Jarlsbergs got pressed at 182 lbs/4.3 psi (I determined accurately later.) and they still retain a lot of whey.
I tweaked my worksheet and feel that it finally gives me a good idea what the hardware is doing. The folks here have helped me a lot with their expert guidance.
-Boofer-
Hi
Some time passed between the first idea of a 2 lever system and it's realisation, but in image you can see what my son build, based on the drawings earlier in this thread. He needed a 100 Kg press for his bookbinding hobby, while I was interested in a 20-50 Kg Cheese press.
The press can be used with 1 lever (x3) or both (x~10), and we hang the weight via an axis so there is another x2 factor (if needed): In the picture we're pressing our first Gouda (with cumin seeds :D ) at 50Kg (4 psi) with only 2-3 Kg of sand
The issue of positioning the plunger with limited travel and limited number of holes is solved by saving little wooden blocks of different height to fill the gap bteween plunger and mould lid.
The 2 vertical beams of the frame are made of pine 68mm x 32 mm, while levers are made of 2x 46x18 mm beams: it holds the forces without cracks !
The bottom plate can be removed (loosening bolts underneath) for better storage.
The whole structure is ~80 cm height and can take moulds till 40 cm diameter/height
The 2 Kg cheese came out nicely and is ageing till at least end of September (8 weeks)
Greetings Amnon
Very nice!
Boofer,
I looked at your worksheet and MAY have figured out why your tested weight looses out to the calculated weight at an exponential rate:
The length of your lever arm may be 48", but you only need to calculate from the point where the weights are attached to where the pivot is installed.
Quote from: Spoons on September 16, 2010, 03:30:38 AM
Boofer,
I looked at your worksheet and MAY have figured out why your tested weight looses out to the calculated weight at an exponential rate:
The length of your lever arm may be 48", but you only need to calculate from the point where the weights are attached to where the pivot is installed.
Am I not? I may be losing a half inch on either end, but that seems negligible. How do you get exponential loss from my data? The 2-pulley side measured loss, but the 4-pulley side measured gain. I found that it is, at best, an inexact measuring system. It gives me a decent "in-the-ballpark" reading. I can see that there is friction loss in the rope-on-pulley component. I could improve that if I substituted stranded wire in place of the rope, but I probably won't do that. I am satisfied that it delivers reasonable psi to my cheeses.
-Boofer-
Boofer great looking press. Very impressive fit and finish.
Great discussion overall, I'm getting lots of formulas that will be very useful for me later. Who knew back in school Math and Physics would actually prove to not only be beneficial but actually crucial to anyone in their everyday life. :) Thanks guys for all the formulas.
Amnon that's a great looking press, you and your son have put together. If you get a chance to take some more pictures of it from different angles I think it could be very beneficial to others who plan on building something similar, or even the same.
Quote from: Boofer on September 16, 2010, 07:58:08 AM
Quote from: Spoons on September 16, 2010, 03:30:38 AM
Boofer,
I looked at your worksheet and MAY have figured out why your tested weight looses out to the calculated weight at an exponential rate:
The length of your lever arm may be 48", but you only need to calculate from the point where the weights are attached to where the pivot is installed.
Am I not? I may be losing a half inch on either end, but that seems negligible. How do you get exponential loss from my data? The 2-pulley side measured loss, but the 4-pulley side measured gain. I found that it is, at best, an inexact measuring system. It gives me a decent "in-the-ballpark" reading. I can see that there is friction loss in the rope-on-pulley component. I could improve that if I substituted stranded wire in place of the rope, but I probably won't do that. I am satisfied that it delivers reasonable psi to my cheeses.
-Boofer-
I wasn't criticizing. I'm just a tad perfectionist at times, Just trying to help out with the spreadsheet. ;D Loosing to friction with the rope makes a lot of sense as well. I haven't thought of that.
BTW, nice work on the press! very effective!
Spoons - I didn't take your observations as criticism. I was genuinely curious how you determined the exponential aspect. Anyone on this forum can attest to my continued need for corrective criticism. I look at it as guidance to put me on the more correct path, unless of course it is hurtful criticism. :( >:(
Guys, thanks for your encouragement.
-Boofer-
Boofer - Yeah, I too would like to see another angle. I am particularly interested in seeing how your pulleys are set up. I love the spread sheet too.
Thanks
Quote from: Brentsbox on September 19, 2010, 09:41:12 AM
Boofer - Yeah, I too would like to see another angle. I am particularly interested in seeing how your pulleys are set up. I love the spread sheet too.
Thanks
Don't know what angle you're interested in. Here are some shots of the pulleys, as requested.
-Boofer-
Are you using 1 or 2 pulleys on the top Boofer? I can tell if I am seeing the lever arm or a pulley. Nice job hon!
Quote from: DeejayDebi on September 22, 2010, 02:45:41 AM
Are you using 1 or 2 pulleys on the top Boofer? I can tell if I am seeing the lever arm or a pulley. Nice job hon!
I think he has a single double pulley at each end. So that gives him a maximum of 5 points for an additional MA of 5. Very very well done.
Boofer what size are those double pulleys (3/4, 1, 1.5) and where did you buy them from (locally or online)?
The size of the pulley itself is just under 1 inch. They are twin pulley blocks I purchased at either Lowes or Home Depot. They give me the flexibility (as shown on the spreadsheet) to use either one pulley at top and bottom or to use all four for maximum MA. I also got the little screw-together connector between the eyebolt and the pulley block from the same place. That keeps it all in one place. I believe those little connectors were rated at 150 pounds.
I don't know if I mentioned it before but the wood is 2"x3" and 2"x8" hemlock. Nice strong wood with few knots or blemishes. Hey, bought it at the same place as above. One-stop shopping. ;)
Works for me. 8)
-Boofer-
Thanks Boofer,
I think im going to give that a try and see what kind of results I get. I made a dutch lever press just last week and am using if for the first time today. Right now I get a good 45 lbs with about 10 lbs of weight. I have been looking at your spread sheet and am looking forward to seeing what kind of psi i am getting. Thanks for taking the time to post the pictures and for doing the spread sheet. Great job!
Just trying to give whatever help I can to those that follow....
You'll see some of my missteps on this forum as well as successes. That gives me a bit of a blog in addition to my personal record-keeping, and lets others walking behind me not step on that same landmine. ;D
If I've helped you at all, why not toss a cheese (https://cheeseforum.org/forum/index.php/topic,284.msg1220.html#msg1220) my way? Thanks.
-Boofer-
Looks really nice and a cheese is headed your way hon!
Quote from: DeejayDebi on September 23, 2010, 01:10:18 AM
Looks really nice and a cheese is headed your way hon!
What a sweetheart. I thought I'd be stuck at 10
forever!
-Boofer-
Gee I though 10 was something special - maybe that was just for Bo Derik. ;)
Quote from: DeejayDebi on September 25, 2010, 03:41:50 AM
Gee I though 10 was something special - maybe that was just for Bo Derik. ;)
I think even she may have slid to something less than a "10" by this time. I think she's getting a little long in the tooth. :) :(
-Boofer-
Probbly that was like late 70's?
Hi Boofer, I'm wondering where you got your awesome copper pot that you show in the pictures on this thread? I'm looking for something similar, although from what I've found, they are expensive, even on Ebay for banged up used ones...!
~Laurie
Quote from: Boofer on May 26, 2010, 05:00:11 PM
On Sunday I made a Gouda following Dave's (aka. likesspace) recipe. On this occasion I used my Extech pH100 meter for the first time. I also used my new small (450g) Kadova moulds for the first time. But the real kicker was that I got to use my newly-built Dutch press.
-Boofer-
Laurie, look for one of these on ebay. you will find it under copper candy kettles. This one holds 4 gallons comfortably but I have another one that is much bigger and will hold about 20 gallons. I paid about $100 for this one.
Have you found any difference in your cheese using the copper pot Brent?
As far as taste, not really. As far as performance, quite a bit. The copper pot is so much easier for me to control the heat. I have a gas stove and can put it on low and it works great to let the temp rise slowly when cooking the curds, say like taking them from 90F to 145F (or something like that) over 45 minutes. Then its real easy for me to maintain whatever temp. I never had that much control with my stainless pot with a heavy bottom. And when i was doing it in the sink with hot water, i was forever going up and down with hot or cold water. So, yeah, from that stand point, it has made a big difference. I am considering having the inside of the pot tinned and have found a guy near by in New Orleans that does that kind of thing and the price is very reasonable but i dont know that it is needed. I use it so often that it dosent get much chance to build up any oxidation and I allays wipe it out real good with vinegar and rinse before using just because it seems like a good thing to do. Bottom line - I love the heat control!
Quote from: WhiteSageFarms on October 14, 2010, 07:56:37 PM
Hi Boofer, I'm wondering where you got your awesome copper pot that you show in the pictures on this thread?
What copper pot? I use a stainless steel kettle that holds 4 gallons. It used to be used in my beermaking efforts, but has been recycled to my cheeserie. The pic shows it inside my aluminum lobster kettle which is now my double boiler.
I'd like to step up to a 10 gallon pot somewhere down the road so that my alpines can produce decent holes. That won't happen until my technique improves and I produce consistent quality.
-Boofer-
Boofer, its on the first post and it sure looks like a copper pot to me too.
(https://cheeseforum.org/forum/index.php?action=dlattach;topic=4026.0;attach=8364;image)
Oh yeah, I see it now...but I can't squint all day. ;)
No, I'm kidding. The rim does have a copperish hue. But the innards sure don't look that way. Must be my rose-colored glasses acting up again.
I wonder how many folks here use stainless or copper kettles? I'd lean towards the former. Seems like copper would be a real pain to maintain and would drive me insane. Is that inane? Sorry, remember the glasses. 8)
I was curious...why would you tin the copper? Seems like that would erode away with use.
-Boofer-
most copper cookware is tinned to prevent oxidation. the tinning is only on the inside of the cookware. Copper can give off small amounts of something, im sure linuxboy can tell you what, but its not enough to worry about though. However, if your cooking at temps over 400F then you dont want a tinned copper pot. Tin melts at 450F
Well Y'all know my vat is a 8" deep SS chaffing dish or hotel pan but for cookware I use thick copper bottom pans for heat control - very old Revere Pro Line series. They worked great for small batches of cheese as well but my biggest is only 2 gallons.
What do you have under the cheese on your press to collect the whey? A friend made me a press very similar to yours, but I haven't used it yet because I haven't figured out what to put under the cheese to catch the whey. I am a newby at all of this!!! :D
What kind of moulds are you using? Are they for hard cheese? When pressing more than one mould, how do you keep the board on top the cheese moulds pressing equally on all 4 or 2 of them? I've been thinking about it and if one compresses before the other the press top would be unlevel, right?
Thanks!
Judy
Use a pot to catch the whey. Just get one large enough to hold the mold you are using then empty it out each time you flip the cheese.
Hi Judy,
Yeah, what FarmerJD said...just about anything will do to catch the whey. One of the pictures shows a broiler pan I used. If it starts to get too wet, just empty it out and put it back under the press.
Up to this point I have been frugal with my mold expenditures. I have a 7.375 inch "Tomme" mold that serves all of my 4 gallon (3+ lb) hard, semi-hard, and semi-soft cheeses so far. I have four 4.375 inch Kadova molds that I have used a couple times for Jack and Gouda. My most recent expense is a 5"x10" SS brick mold. It has yet to see service but I anticipate a repeat try of my Esrom with that mold which would be closer to the cheese style.
I built my press so that I could stack molds vertically or spread them out. I've shown the small Kadovas being prepressed under whey and in the Dutch press with a cutting board to spread the pressure somewhat evenly.
I show two ways that I press under whey. I know you didn't ask that, but I thought I'd throw it in anywhey. In both cases, the pot should be covered and the warmth should be preserved.
Hope this answers some of your questions. Keep asking.
-Boofer-
I happened to be combing through some pics I had used when designing/building my press. One that really seemed to convince me to design in the 4-pulley system may be useful to other folks. By merely adding some pulleys to the system, the overall pressing capability is improved tremendously.
The pic illustrates that when you add a pulley, the force required to achieve the target pressure is reduced, but the distance required to pull on the rope (and achieve the target pressure) is increased.
-Boofer-
Moulds for Italian cheese - Fresh Cheeses, Mature Cheeses, Brie, Caciotta, Fresh Goat Cheese, Camembert, Primo Sale, Robiola, Crescenza o Stracchino, Taleggio, Mozzarella Fiordilatte, Ricotta, Yogurt, Dolci
http://alcofermbrew.com/en/Multipacks-c65.html (http://alcofermbrew.com/en/Multipacks-c65.html)
(http://alcofermbrew.com/image/cache/catalog/Cheese%20kit%20vik/Italian-Cheese-Kit-600x600.jpg)
http://alcofermbrew.com/en/Cheese-kit-for-homemade-cheese-p832c65.html (http://alcofermbrew.com/en/Cheese-kit-for-homemade-cheese-p832c65.html)
It seems like no one is ever around any longer, which is sad. I know it's been so many years but I just want to say to all the "old guard" I hope you are well and happy. And to the webmaster, so much gratitude for founding this and keeping it going. And to the newer people, from an oldster now, best wishes on all your ventures in this wonderful hobby. It's nice to be back cheesemaking again.
I actually built a press almost exactly on Boofer's design and it worked great - regularly made 8" wheels of what we called "Beaufort" here, most of us taking our starting point from SailorConQueso's excellent threads, pressing up to 4 psi, maximally, if I recall correctly. Eventually I went to true Abondance, 10 kgs or so, with the unique concave alpine hoops and a massive screw press.
But it's been too long. I know Boofer used 2 x 8's and 2 x 3's, as well as 1 x 1 steel rod, but can't recall if he ever gave dimensions on his cut lumber for the build. I know the one I built was probably way too huge - the bottom length alone made it a major project to haul in and out on cheese day. So if anyone might have Boofer's original dimensions, that would be great.
I don't have his original dimensions, but I built a Dutch-style press for myself out of walnut wood a couple of years ago that I've used with over 100 lbs of pressure. I only ever need it levered up that much when pressing cheddars. I'd be happy to share pictures and measurements of mine if that would be useful.
I've been able to press cheeses up to about six inches in height, and up to around 10-ish inches in diameter, although that gets pretty hard to fit.
I made a gruyere a few months ago (5 months left to age) that I had to build an adjustable hoop for, as I don't have any hoops big enough otherwise. I didn't use the press in that case, I just tightened the hoop and kept a cutting board on top with a weight on it, and that seemed to do well enough. The hoop was made out of stainless steel flashing, and I had a hard time not cutting myself a bit on it when tightening it, so that will need some fixing.