Randy

Hydraulic press for forging?

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I just received this message from one of our members:
 
Merry Xmas, Randy. I saw you wrote a book and I've wanted to get it soon. I was wondering if you'd say something about folks who say run away. As they think forging with presses is foolish?

Like most any subject, I've found most are scared of what they don't understand most times. I don't know much about this type of operation and I’m very interested in any thoughts per se.   Thanks

 
Personally I’ve never heard anyone say those things in regards to the forging press, but I’ll address it for you in case that concern is out there.
 
Hydraulic forging presses have been used to move hot iron and steel since about 1861. It started in major industrial companies with presses in the hundreds and thousands of tons. By the late 1800’s they had also moved to the blacksmith shops, but in a much smaller size, usually 200 tons or less. It didn’t take long for the smiths to see the benefits of its power and control, besides its versatility in forging operations.

We have the knife makers to thank with coming up with the powerful, small footprint, homemade forging press of today. Besides making this piece of equipment economical it has added another versatile tool for moving hot metal. When I asked smiths that use the press what they most like about it the answer was almost always, “control, control, control”.  Whether for forge welding billets of damascus steel, punching holes, drawing out bar stock, making repeated designs with dies plus a number of other operations, the hydraulic forging press is a incredible machine for the blacksmith shop. It is so versatile that I even sold my Nazel 1B air hammer which I had used for over twenty years due to my press being able to do as much as it could do and more.
 
My new book, “Hydraulic Forging Press for the Blacksmith” explains the differences in the major forging equipment, it helps you decide what type of press would work best for what you want to make, goes over safety issues, shows tooling and how to make it for your press and has a gallery in the back of smiths from around the world with their presses, tooling and what they make using it.
 
Perhaps the so called idea of the press “being foolish” is based on either the safety issues or with shop presses or other presses not meant for forging.
 
Yes, there are safety issues with the press, but as with any piece of equipment education is the key to safe operation. These rules of safety must be followed. One line that I wrote in my book that describes this best is, “Power does not ignore ignorance, it magnifies it!” 
 
I have seen shop presses, those flimsy often bottle jack propelled presses that you can buy for hundreds of dollars, used in the forging shop, but I do not recommend them for forging. They are too slow and the framework is not meant to withstand the power exerted in forging. There are exceptions in everything, but the common shop press usually will not work for forging, so it’s okay to “run away” from those.
 
I hope this has helped to clarify this issue. If you want to learn more about the hydraulic forging press find a local smith who uses one and talk to them about why they like it.
 
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I have seen one of Randy's presses in action and it is awesome!  Hard to believe what you can accomplish with controlled power, and what it can do.

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With twin cylinders you get more piston square inches. This allows you to run a higher volume ,but lower pressure pump, with equal results to a single cylinder with lower volume higher pressure pump. Correct?

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Area and volume are gonna be the same regardless of one or two cylinder. Smaller bore cylinders are a lot more common (cheaper) on the surplus market

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Grundsau, Yes you can.
 
Brianc has it right. It's just less expensive to buy two six inch cylinders than one twelve inch.

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Correct, area and volume aspects still apply, but lower pressure pumps are usually a lot higher volume output in my experience. So with two cylinders you could match the power output with faster piston speed if the components are matched up correctly.

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I'm well aware of the math (design mobile hydraulics for a living). One question I did have with the two cylinder design was did Randy use any flow division to synchronize the cylinders. When he was using the wide combo dies and one side hit first, the other cylinder is going to get all the flow, wracking the platform and throwing a lot of extra stress into guides and frame. As long as the design allows for it, this will work but there are hydraulic solutions for this as as well.
One other thing regarding 1 big vs two small cylinders and speed would be the plumbing. A bigger cylinder will have larger ports allowing for more flow. Two cylinders will have slightly more complicated plumbing. It's splitting hairs, but I'm a big fan of neat, tidy hydraulic plumbing, have seen a lot of hairballs out there. Use bigger hoses, sweeping bends, as few 90 degree fittings as possible and you will have a more efficient, cooler running system.
Whew...

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I did not design this press, but bought it designed and the frame ready to go. I had to get the balance of the plates and build a mechanicals cart and assemble it. He then came over and did the plumbing. The man who designed it has built many presses and uses Batson's book to figure most things out. He also works along with the local hydraulics company if he has any additional questions or concerns. 

 

Equalizing pressure between the cylinders was one of my concerns, too. They do sell synchronizers for this purpose, but he explained that the pressure between the cylinders would balance on their own as they are hooked up in tandem and the pressure would flow equally to both cylinders.

 

He was exactly right. There has never been a problem with one cylinder operating faster or slower than the other and both sides come up and down equally.

 

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I have seen shop presses, those flimsy often bottle jack propelled presses that you can buy for hundreds of dollars, used in the forging shop, but I do not recommend them for forging. They are too slow and the framework is not meant to withstand the power exerted in forging. There are exceptions in everything, but the common shop press usually will not work for forging, so it’s okay to “run away” from those.

How powerful does a press need to be to be useful? I was vaguely considering getting a 6 ton bottle jack press for £60 off ebay until I saw this.

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How powerful does a press need to be to be useful? I was vaguely considering getting a 6 ton bottle jack press for £60 off ebay until I saw this.

If it moves fast you can get by with low tonnage...say 16 ton. If it moves slow you may need 1,000 ton to get anything done.

I would say a minimum for hot forging is about .3 inches per second..........and no faster than 2" per second as it posses a safety risk and the hoses get to jumping when the oil changes flow.

 

If you have large die surfaces you need more tonnage. Assume about 8 ton per square inch to forge mild steel and triple that for carbon stainless.

Thinner metal needs more tonnage as the dies bleed the heat. You can use up a lot of tonnage if you just stick the material under the die and go.

 

Creative die design can overcome many issue with a hyd press, but in the end I prefer big and fast.

I can think of many things that can be done with 16 ton and some things that 2,000 ton can not do.

 

Ric

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