Author Topic: pneumatic press questions  (Read 3587 times)

Offline Just Plain Fred

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Re: pneumatic press questions
« Reply #15 on: November 04, 2013, 10:19:58 AM »
Dead weight changes, but PSI is a standard that doesn't change from hoop to hoop. While you should use a different "weight" on a 4" or 8" hoop, the PSI remains constant.

"Sailor",

 Hello... Guess I'm missing something... ( block of Cheddar brain)  Let's take two extreme cases... If you had a 1" rod pressing down at 100 PSI ..well simple 100 psi... Next case you have a manhole cover (36") with the same 1" rod at 100PSI .. The 100PSI would be distributed over the square inches of the 36" cover (1017sq in) Am i over thinking this?...Regards Fred
 


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Offline Just Plain Fred

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Re: pneumatic press questions
« Reply #16 on: November 04, 2013, 10:23:43 AM »

@120 PSI air pressure , a 2" diameter will exert just over 360 pound of force on your cheese.

A 4" cheese will have a surface area of about 12.5 inches.

So 360 pounds divided by 12.5 is just under 30 PSI exerted on a 4" cheese.



 jwalker

Hello... Thanks Much for your responses ...Yes i agree (i think) Then why isn't this weight given for the different size molds? Wouldn't everyone need to no this before you end up with too low a press weight... Regards Fred

Offline jwalker

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Re: pneumatic press questions
« Reply #17 on: November 04, 2013, 11:01:47 AM »
Fred , don't get too concerned with high press weights , I am fairly new at this , been making cheese for about a year , and I started with R Carrolls book which reccomends  pretty high weights.

All of my original hard cheese came out very hard and dry , as well as bitter.

So I reduced my weights considerably , and my latest versions are coming out very nice with about 3-4 PSI , even Cheddar.

I think one of the things that contribute to this is the fact that I use store bought milk , the curds tend to break up very small and lose a lot of whey in the process , so less press weight results in retaining more whey , for a softer  more palatable cheese.

I think there is more to press weight than some think , type of milk , size of curd , washed curds , temperature of wash , temperature of curds when pressing , time in the press , salting methods , and just plain old personal preference.

I think you'll find your press will do the job.
No..........I'm not a professional CheeseMaker , but I play one on TV.

Offline artguy

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Re: pneumatic press questions
« Reply #18 on: January 05, 2014, 11:50:35 AM »
Just Plain Fred 

Would you be willing to share the dimensions of the thread and square stock parts you made as well as the size of piston you used?   Love your press.  A friend of mine is a machinist and we were looking to fabricate a press.  Your design is very intuitive and impressive. Please?............:)

Offline Just Plain Fred

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Re: pneumatic press questions
« Reply #19 on: January 05, 2014, 01:24:16 PM »
artguy,
 Hello... would be happy to help

1. Thread size is a 1"X 8 TPI ...With drilled and tapped 1\4" X 20 holes on the ends of the "rods" ..I used  1" hot rolled steel stock ( couldn't find cold rolled 1" stock at the time) ..Note  cut the threads (Lathe) on the "Loose" side ( approx 50 % engagement)  so they can be "spun" with just a "quick flick" also file the threads flat with a file when finished so you don't cut yourself when spinning the SS nuts.

2. The Square tubing is standard 2"x 2" x .180 stock  2" will work best for "Air Cylinders in the 2" diameter size.

3. The double stroke cylinder is a "SPEEDAIRE"  2" x 12"

Post back if i can be of any further help...Regards Fred

PS: I have made a few "Mods" since ... i will post a new pic as soon a i can find my camera... Added a  more sensitive pressure gauge ...etc


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Offline Just Plain Fred

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Re: pneumatic press questions
« Reply #20 on: January 05, 2014, 01:58:17 PM »
artguy,
 Don't know how to add the "pic" in my original post so this is the only way i can

1.  Added SS washers on the top and bottom so the nuts don't dig into the tubing.

2.  The pressure gauge is a 60 PSI unit as the multiplication factor is X3 for a 2" cylinder , allowing for a max force  of Approx 180psi on the ram... should be more than enough for "Cheddar" using a 4" or 6" mold... If not, i can always swap it out for one of higher value and put more initial pressure from the main regulator

3. Pay attention on how you hook up the 3 way valve ... i had reversed the "P"(Input)  and "R" ( Exhaust ) and the valve leaked air  A & B are ( up and down) outputs

Offline artguy

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Re: pneumatic press questions
« Reply #21 on: January 08, 2014, 08:31:45 PM »
How much would you charge if someone were to commission one that has a fixed height with no threaded stock and a cylinder with a shorter stroke?

Offline artguy

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Re: pneumatic press questions
« Reply #22 on: January 08, 2014, 08:36:13 PM »
Wanted to clarify.  I am having a hard time getting scheduled into our metals shop.  What I really need help with is fabing the metal structure and cutting board for the whey.  Then I have no problem getting the parts and assembling it.  Found all the pneumatic parts you listed previously.

Offline Just Plain Fred

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Re: pneumatic press questions
« Reply #23 on: January 09, 2014, 08:55:54 AM »
Wanted to clarify.  I am having a hard time getting scheduled into our metals shop.  What I really need help with is fabing the metal structure and cutting board for the whey.  Then I have no problem getting the parts and assembling it.  Found all the pneumatic parts you listed previously.

artguy,
 
 Hello... I used "threaded rods" in my design because.... When using open end molds my thought was to secure (hold down) the top of the mold with the upper bar. This would prevent the curds from trying to squeeze out ("lift up" ) the mold under heavy pressure. I am an "old retired guy" and only reckon that i have only a few more years left on my contract ( threescore and ten) So... i don't "hire out" any longer. Your best bet would be to find a local shop to "cut" (thread drill and tap) the bars and mill out the tray ... Regards Fred

Offline artguy

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Re: pneumatic press questions
« Reply #24 on: January 09, 2014, 04:54:03 PM »
no worries, understandable.  Could you tell me this.  If I were to make the press a fixed height what would you suggest for the interior dimension for standard sized molds?  Keeping in mind I would be using 2" stock, what length stroke should I get when I purchase a cylinder?  Thanks for answering all these questions from a beginner.  If I go to a fixed height press I will have a better chance of being able to make it at school as it will not require as much advance machining processes.




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Offline Just Plain Fred

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Re: pneumatic press questions
« Reply #25 on: January 09, 2014, 05:48:19 PM »
artguy,

 Hello... I'm a beginner also ...my best best guess answers...

 1. For interior size .. this all depends on the mold height. I have 8" ( 4" and  6" diameter ) I've seen some that are only 4" in height ...So you have to be the judge as to which type of mold height your looking at ... If your going to use a single 4" high closed bottom mold ...i would go with a 8" to 12" interior height

 2.  As to the ( Dual ) cylinder size ... there is not much difference in price in a 2" cylinder whether the stroke is 8 " or 12" The 2" cylinder diameter is a nice compromise as it gives an (Approx)  3 x   multiplication over your input pressure, and doesn't use much air. Also...  fits on to a 2" square tubing stock with only a slight "Mod" of the connecting nut.

 3. The frame still would require welding for the base ...

 4. I would wait and build the "Adjustable" version from the "Geko" ... this way you won't "out-grow"  it down the road when you want to make a different type of cheese ...Or want to press out a wheel bearing...Regards Fred

Offline artguy

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Re: pneumatic press questions
« Reply #26 on: January 09, 2014, 08:41:58 PM »
Thanks for you help Fred.
Cheers


Offline artguy

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Re: pneumatic press questions
« Reply #27 on: January 12, 2014, 09:57:01 AM »
quick question for you fred, what is the additional length you have added there to the 2" square stock to accommodate the regulator and valve?

Cheers


Offline jwalker

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Re: pneumatic press questions
« Reply #28 on: January 12, 2014, 10:36:46 AM »
artguy, ...Or want to press out a wheel bearing...Regards Fred


LOL!! ;D ;D ;D
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Offline Just Plain Fred

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Re: pneumatic press questions
« Reply #29 on: January 12, 2014, 10:53:42 AM »
quick question for you fred, what is the additional length you have added there to the 2" square stock to accommodate the regulator and valve?

 artguy,
 
  Hello... The Base is 16" x 16".... and the top member is 21" in  length...
Regards Fred...

PS: One other thing...The "Holes" drilled into the upper bar are 1 1\4"  and then fitted with some "Bushings" made from the 1" cutting board stock. They are not visible on the picture..there inside the 2" x 2"  and attached with 6x32 flathead screws..This lets the upper bar "Slide" easily up and down the screw threads without jamming.

« Last Edit: January 13, 2014, 06:13:19 AM by Just Plain Fred »