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I Forge Iron

Press from Harbor Freight


CreekSideForge

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I am building a forging press using the HF air over hydraulic 20 ton jack and I am welding up the frame.

This is more for knocking bushing out and pressing things that don't want to move. Check YouTube using some or all of these key words "air over hydraulic 20 ton jack".

Ernest

 

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I have built one of the small presses using an air over hydraulic jack and after you do, you'll realize that they work OK for really small things. They mash a hot piece of 1/2" but they are still too slow and really don't hit the max (20 ton) pressure until you are nearing the end of the pressure curve which takes a while to reach. My 27 ton log splitter is about a 100 times more versatile. But as I said I built one after watching the Youtube videos, now it sits in a corner and I use it occasionally for copper.

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9 hours ago, Fatfudd said:

nearing the end of the pressure curve

I don't know enough about the hydraulics to understand this statement. Would this mean when the jack is fully extended? The log splitter option is on my list of things to look for, have you posted a photo of your splitter/press? I want to make a proper hydraulic press but I am limited in funds, space and voltage right now. I am willing to start small but I am trying to build my press so I can change out the jack for a hydraulic cylinder down the road.
Ernest  

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8 hours ago, SLAG said:

Harbor Freight has recently starting offering a fifty ton press. (I noticed it about 8 months ago  on their website), & in their catalogue.   

Does anyone have any information, and an opinion about it?

SLAG.

 

Its much slower, kind of like working a regular hydraulic press by hand.

11 minutes ago, eseemann said:

I don't know enough about the hydraulics to understand this statement. Would this mean when the jack is fully extended? The log splitter option is on my list of things to look for, have you posted a photo of your splitter/press? I want to make a proper hydraulic press but I am limited in funds, space and voltage right now. I am willing to start small but I am trying to build my press so I can change out the jack for a hydraulic cylinder down the road.
Ernest  

It means as the ram encounters the item to be lifted(or squeezed)  the pressure begins to build. As the pressure begins to build the ram moves more slowly. As it nears the end of it its weight lifting capability you begin to get close to the top if its pressure curve or the 20 ton lifting capability. This is similar to a regular hydraulic cylinder(in a press or log splitter) but because of the speed of the ram you get the pressure spike much quicker.   

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Fatfudd,

I think I get it now. So that would mean you would have to leave it on the press until it is squeezing for all it is worth and at the same time watch all your heat get sucked out by the top and bottom dies. So this sounds like a problem of efficiency. If you were pressing using just the air you might get a unit of force we can call 10 Units Of Smash (UOS) at a give speed. But since you are using the air to drive the hydraulic action you might get 10 UOS less any overhead lost due to friction and at lower speed.

If you had a pump moving a hydraulic cylinder you might get the same number of UOS BUT at a greater speed.

What I am building requires a compressor motor to compress air, the air to power a hydraulic pump the pump to move the jack BUT when you have a motor directly moving the hydraulic pump you remove that extra overhead.

If I am not making any sense you are welcome to tell me and I will not take it hard since I know I know very little about this subject.

Ernest 

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For what it's worth, I welded up a similar press many years ago and swapped out the hand pumped bottle jack for an air assisted 20 ton bottle jack.  I built top/bottom dies for it and added die plates so I can just slide the dies in/out.  The press is much slower than a regular hydraulic forging press, but it works.  I also added a small tabbed handle to the pressure release screw so I can release the pressure quickly enough to get a second or third squeeze in one heat.

 

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On 12/28/2017 at 5:33 AM, eseemann said:

Fatfudd,

I think I get it now. So that would mean you would have to leave it on the press until it is squeezing for all it is worth and at the same time watch all your heat get sucked out by the top and bottom dies. So this sounds like a problem of efficiency. If you were pressing using just the air you might get a unit of force we can call 10 Units Of Smash (UOS) at a give speed. But since you are using the air to drive the hydraulic action you might get 10 UOS less any overhead lost due to friction and at lower speed.

If you had a pump moving a hydraulic cylinder you might get the same number of UOS BUT at a greater speed.

What I am building requires a compressor motor to compress air, the air to power a hydraulic pump the pump to move the jack BUT when you have a motor directly moving the hydraulic pump you remove that extra overhead.

If I am not making any sense you are welcome to tell me and I will not take it hard since I know I know very little about this subject.

Ernest 

You're correct, The compressor/air combo is much slower than a direct drive to the hydraulic pump. I built mine the same as Olfart describes and as I said it'll squash a piece of .5"x.5" real nicely but I can't get it to do work any faster than if I do it by hand. Actually its slower because the ram moves so slowly, does suck out the heat rather quickly and also because it  uses a lot of air, even with a 60 gallon compressor tank. You would wind up waiting for the compressor to recharge if you have a smaller compressor.

My 27 ton log splitter is actually much better (for me) than alot of my friend's stationary forging presses, Its mobile, costs about 75% less than their presses and allows much more space for the forging processes. Since I don't use it all the time I can just push it outside and leave it when i don't need it but it only takes about 5 minutes to set it up to run.

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