Chem Posted December 3, 2020 Share Posted December 3, 2020 Hey everyone. I recently built a hydraulic press without any plans. It has a 5hp electric motor powering a 2 stage 19 gpm pump. Originally it had a 4 inch bore with a 12 inch stroke. I was disappointed with the power. I replaced the ram with a 5 inch 10 inch stroke. It helped a small amount, but I'm still nowhere where I should be. Any help would be appreciated Quote Link to comment Share on other sites More sharing options...
Frosty Posted December 3, 2020 Share Posted December 3, 2020 Welcome aboard Chem, if you put your general location in the header you'll have a chance of hooking up with a member who lives within visiting distance. You've run into the biggest problem building something without plans or knowing how the work. When you say powerful I have to assume you mean it lacks pressure against the bottom die. A 5" dia piston only has around 19 sq in area. The pressure a hydraulic piston can produce is determined by the lbs/sq inch the pump produces x the square inches of piston area. GPM determines the speed the piston advances and has zero to do with ram pressure. Your 5" piston produced 158% the ram pressure the 4" piston did. That's simple arithmetic, I'd tell you the tonnage but I don't know the pimp's psi rating. Building hydraulic systems isn't a matter of getting some stuff and putting it together, Hydraulic systems are inherently dangerous when built correctly, a pinhole in the wrong place can slice you open like a laser scalpel. You should pick up a book on hydraulics at a hydraulics shop or get some titles and check them out at the library. Do NOT build your press following online videos! They range from mostly bad designs and construction to downright foolishly dangerous. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
Deimos Posted December 3, 2020 Share Posted December 3, 2020 What pressure are you working on? Do you have any control over said pressure? Do you have pictures of your setup? What kind of cylinder are you using? (telescopic, plunder) Did you make the cylinder yourself? What kind of seals does it have? Are you using a accumulator? I worked with hydraulic systems for a few years and know a bit about them, but I need a lot more information before I can give you advice. And what you did so far was not the smartest thing. To continue on what Frosty said, oil under pressure is very very dangerous. I would rather zap myself with 230 Vac then have oil penetrate my skin (can happen very easy with a small pinhole) Why? Because the oil will spread under your skin, and there is no way to get the oil out of said skin. Once worked with a fool who tried to find a leaking hose inside of a pump reservoir, he found the hole with one of his fingers. The oil penetrated his skin and he thought not much of it when they brought him to the hospital. One surgery later he was a one armed man. Quote Link to comment Share on other sites More sharing options...
pnut Posted December 3, 2020 Share Posted December 3, 2020 If you can find a copy of this book it explains all the math needed to build a press. It's a textbook from a class. It even has review questions. Pnut Quote Link to comment Share on other sites More sharing options...
teenylittlemetalguy Posted December 3, 2020 Share Posted December 3, 2020 2 stage pumps wear out really easy, it can still turn and sound just fine but leak like a sieve inside robbing you of power. If it was me I would try a new one, they are usually cheap. I would also go back to the smaller cylinder so you can have the speed you need to work hot steel before it cools. a bigger cylinder is more tonnage but way slower. Quote Link to comment Share on other sites More sharing options...
bubba682 Posted December 3, 2020 Share Posted December 3, 2020 Something is off cause i got the same set up my press is fast with the 5x10 ram and i'm pretty sure my pump is a little smaller i ain[t no expert but you should be fast and have alot of squeeze so something is defiantly not working right.What is your reservoir capacity mines 5 gallon Quote Link to comment Share on other sites More sharing options...
Chem Posted December 4, 2020 Author Share Posted December 4, 2020 (edited) 18 hours ago, Deimos said: What pressure are you working on? I worked with hydraulic systems for a few years and know a bit about them, but I need a lot more information before I can give you advice. Im no fool. I was attempting to post a short question, to keep it simple. I have studied hydraulic systems for a couple of years. I have McDaniels forging book. I loosely built my system around one of his examples. I'm not sure what an accumulator is. My psi is regulated by my control valve. I have it set at 2200 psi. The system is theoretically capable of 3000 psi max, but truthfully I didn't want to run it close to max. I bought my cylinder, I'll have to check the brand and seals. I would be happy to get a couple of pictures in the morning. Is there anything specific I should get a close up picture of? 6 hours ago, teenylittlemetalguy said: I would also go back to the smaller cylinder so you can have the speed you need to work hot steel before it cools. a bigger cylinder is more tonnage but way slower. Actually I really didn't see much of any difference in the ram speed between the two different cylinders. I did notice some increase in crush power, but as I said, it still isn't where it should be. A friend has a 4 ton electric log splitter that he converted into a press. He has almost as much power as I do. 3 hours ago, bubba682 said: Something is off cause i got the same set up my press is fast Yeah that's my thoughts as well. I think It must be something simple that I'm missing, but I've gotten nowhere so far. My tank is 10 gallon, but I have about 8 1/2 gallons in it for expansion. Edited December 4, 2020 by Mod30 Excessive quoting Quote Link to comment Share on other sites More sharing options...
Chem Posted December 4, 2020 Author Share Posted December 4, 2020 On 12/3/2020 at 4:34 AM, pnut said: If you can find a copy of this book it explains all the math needed to build a press. It's a textbook from a class. Ok, I'll look into it. I was a little disappointed with the lack of information in Randy McDaniels book. Thanks Quote Link to comment Share on other sites More sharing options...
Deimos Posted December 4, 2020 Share Posted December 4, 2020 https://en.wikipedia.org/wiki/Hydraulic_accumulator Must be lost in translation then, since accumulators are as well knows as pumps in hydraulics Some pictures of your cylinder, hose/pipes, pump and controls will give me a good idea of what you are working with, since the cylinder is bought (and with that I guess it is brand new) the seals should be good and not be your problem. Also, measure your pipe/hoses, maybe they are way to small for the amount of oil your try to force trough them and that creates lots of turbulence in the flow. Is the pump outfitted with a safety valve? Or is it just the control valve? Quote Link to comment Share on other sites More sharing options...
Chem Posted December 4, 2020 Author Share Posted December 4, 2020 Oh, scratch that. Maybe I do have some "fool" lurking somewhere in my genome, because I don't ever remember reading anything on accumulator in any of my research. Im sending pictures of my press body and the separate power pack located on the other side of my shop wall. Hopefully someone will see something I missed. If you can't tell from the photos, my hoses are half inch. They are mostly 24 inches in length with the exception of the two passing through the wall. They are both 48". Before anyone gets mad at me, I do have a steel plate protecting my hoses from hot slag. Its pretty big, so removed it so I could get better pictures. Thank you for taking the time to help. I signed up to this site some time ago, but "got busy" and haven't really been on much. After I posted my last question, I've gone back and read a mountain of chat. Im am so impressed with the brotherhood on this site! Its awesome to see everyone giving freely; sometimes a lifetime of hard earned experience in blacksmithing. Thank you all. On 12/3/2020 at 2:10 AM, Frosty said: Welcome aboard Chem, if you put your general location in the header you'll have a chance of hooking up with a member who lives within visiting distance. Hi Frosty, I'm a little computer "Special" so you may have to bear with me. I think i posted my info on the header,after your suggestion to do so, but I'm not positive. After my last question I went back to see if anyone had similar problems with a hydraulic system. I found a post where you were explaining the difference in how a cylinder preforms between in and out ram stroke. Could you try to explain that some more, but please try not to get any math on me. Quote Link to comment Share on other sites More sharing options...
Deimos Posted December 4, 2020 Share Posted December 4, 2020 flipping the cylinder 180 degrees will do wonders. Quote Link to comment Share on other sites More sharing options...
Fowllife Posted December 4, 2020 Share Posted December 4, 2020 What is flipping the cylinder 180 going to help? With this design the cylinder will always be retracting to apply pressure and not extending. Depending on your flows and pressures on both the high and low sides of the 2 stage that seems like too big of a pump for only a 5hp motor. I would step back and look at all the pieces of your press and analyze all of the pressures and flows from start to finish. Every piece has a rated pressure and flow, make sure they are within your design perimeters. There are a lot of resource online to help you work through all of your pressure & flow numbers along with expected speed and HP requirements. All of the details matter and are needed to find the answer. Accumulators are not that common over here in the US and most systems don't use them. Quote Link to comment Share on other sites More sharing options...
swedefiddle Posted December 4, 2020 Share Posted December 4, 2020 Good Morning Chem, The surface area of the piston is greater on the end of the piston, without the rod/ram. You are losing effective pressure by 'pulling' the ram together, instead of 'pushing' the ram/piston. Hydraulic systems are mathmatic. Working pressure on the surface diameter of the piston (pi x R2). Neil Quote Link to comment Share on other sites More sharing options...
Deimos Posted December 4, 2020 Share Posted December 4, 2020 Yup, what Swede said, he wanted an answer without math. If you use a cylinder you use the part that has the most force, not the part that has the least force. 50% more surface, and also you are move a lot less oil when the cylinder is flipped, right now you are putting in 19gpm (if you go full flow) and have to move double that from the piston side of the cylinder. Guess how much force that takes. If it is flipped you extend the cylinder with 19gpm, with pressure over the entire surface (so without the rod) and you only have to move 9,5gpm from the rod side (which removes a lot of pressure from the return hoses). The 1/2" hoses should be big enough, we used those on 100 L/min and 160 bar, but I think that T-piece with the meter is pretty small. I would make the following change from that setup with the meter: change the EW (elbow) to a ET (T with a nut in the middle), put the hose on one side, and use a GZ (2 nuts connected back to back) to connect the meter. This will remove a lot of friction. Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted December 4, 2020 Share Posted December 4, 2020 I'm following along, but I admit I'm a bit confused here. I get that the "push" is stronger than the "pull" and the reasons for it. What I don't get is how flipping the cylinder 180 degrees will make any difference. In the current configuration or with the cylinder flipped 180 degrees it's still using the "pull" of the cylinder to apply the pressure. Wouldn't it require redesigning the system so that the top die was stationary with the bottom die movable to accomplish the goal of using the "push" action of the cylinder? Either that or mounting the cylinder overhead to push the top die down, but again that's a frame redesign. What am I missing? Quote Link to comment Share on other sites More sharing options...
Deimos Posted December 4, 2020 Share Posted December 4, 2020 Also switch the hoses. Just a question, the frame of the press, was that a home made or bought? Since I have a good idea why you are having trouble with the hydraulics, i also see some things in the design that bother me. Moving pieces where the pain is scraped is never a good sign. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted December 4, 2020 Share Posted December 4, 2020 As it stands it applies pressure to the dies by pulling down on the moving die holder. It does this by pushing oil into the part that has the piston rod mounted in it---so the smaller area to apply force on it. If you flipped the cylinder and redid the connection so it was attached to the base of the bottom die holder then the full size of the piston would be applying pressure to pull the top die down. Reminiscent of the pneumatic KA 75 powerhammer that a friend of mine has. I prefer systems with a stationary frame and only the die moving on the end of the piston myself. Easier to beef them up for upgrades for more pressure. Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted December 4, 2020 Share Posted December 4, 2020 I guess I still don't get it. It appears that in either configuration the oil has to flow into the portion of the cylinder that contains the ram in order to retract the ram and provide downward pressure on the top die. Why would the retraction force of the cylinder be any different whether the cylinder was mounted base up or base down or even horizontally? Doesn't the surface area remain the same on the ram side of the piston? I can't see how flipping the cylinder allows the greater surface area of the other side of the piston to come into play. It's still pulling the ram in rather than pushing it out, right? Does it create vacuum/low pressure by pulling the oil out of that side of the cylinder rather than just pushing oil into the other side? Quote Link to comment Share on other sites More sharing options...
Deimos Posted December 4, 2020 Share Posted December 4, 2020 now you are putting pressure on the rod side (to pull the die down), you want to put pressure on the other side of the cylinder. So disconnect the hoses, flip the cylinder and connect it back up again. So the hose do not change position. Just do as we describe and see if it changes things. There are not many more ways I can explain it without making a full on drawing and diagram. Quote Link to comment Share on other sites More sharing options...
Buzzkill Posted December 4, 2020 Share Posted December 4, 2020 I get that we want to use the cylinder to "push" rather than "pull." I just don't see how that can be accomplished without changing some combination of the frame and the movable portion that holds the top die. Simply flipping the cylinder 180 degrees and attaching it to the same points doesn't change it from "pull" to "push." There does not appear to be enough room between the top of the frame which holds the bottom die and the bottom of the movable portion that holds the top die to install the cylinder so that it can "push" the top die down without some extensive modifications. Quote Link to comment Share on other sites More sharing options...
Deimos Posted December 4, 2020 Share Posted December 4, 2020 Do you want the problem to go away or do you want to understand basic hydraulics? I can give you A, don't have the time for B. Quote Link to comment Share on other sites More sharing options...
JHCC Posted December 4, 2020 Share Posted December 4, 2020 Buzzkill is correct; without changing the location of the cylinder within the press, flipping the cylinder itself isn't going to do anything. You're still going to be pulling the moveable die down onto the fixed die by retracting the piston, regardless of whether the cylinder is right-side-up or up-side-down. However, if the frame that holds the moveable die is lengthened and the cylinder is mounted between that frame and the underside of the fixed die, then the moveable die moves downward when the piston is extended, which -- as noted above -- exerts more power than retraction. Quote Link to comment Share on other sites More sharing options...
Chem Posted December 4, 2020 Author Share Posted December 4, 2020 7 hours ago, Fowllife said: What is flipping the cylinder 180 going to help? With this design the cylinder will always be retracting to apply pressure and not extending. Alright, I thought I'd missed something. Quote Link to comment Share on other sites More sharing options...
Deimos Posted December 4, 2020 Share Posted December 4, 2020 Having it drawn out myself i see my error indeed, the pulling part of your machine made my thinking go all wonky (and translating English to Dutch and back. Will get back with a solution, but I am afraid it will need some change in the overall design. Quote Link to comment Share on other sites More sharing options...
Chem Posted December 4, 2020 Author Share Posted December 4, 2020 7 hours ago, swedefiddle said: The surface area of the piston is greater on the end of the piston, without the rod/ram. You are losing effective pressure by 'pulling' the ram together, instead of 'pushing' the ram/piston. Hydraulic systems are mathmatic. Working pressure on the surface diameter of the piston (pi x R2). How big of a difference are we talking about? Enough to make a difference? As I understand a hydraulic piston, the pressure is diverted from one side of the ram to the other. Both lines and holes are the same size and the pressure is the same in both directions. The pump doesn't know which way the pressure flows. Quote Link to comment Share on other sites More sharing options...
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