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Jim Deering

C-frame hydraulic presses

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Hello fellow press enthusiasts!

 

I'm looking at making a C-frame hydraulic press, as I have recently obtained a Ø6.3-in single-acting hydraulic cylinder. At 2000psi that's 28t, 2500, 35t and 3000, 42t, so it ought to have enough force to be a handy gizmo. There is still some experimentation needed to determine what the cylinder can actually handle before I settle on the system pressure, hence the range of pressure and force noted in the preceeding... Chasing a maximum ram speed of 2 1/2-in per second

 

Retraction of the large single-acting cylinder is already figured out, so don't worry about the fact that the "pusher" is only a one-way item

 

Having considered such configurations as H-frame, four post, inverted [ram pushing up that is] and so on I think, for what I plan on using it for, a C-frame gives the best access and clearest die and tooling space. After all, it the most common frame type for hammers, be they pneumatic or spring types

 

Considering making it capable of using dies from one of my hammers by machining the rod end to accept those dies, as it saves on making numerous dies from scratch... Tapered key and dovetail fixing

 

I read on a forum here recently that there is a thorough dissertation in an early version of Machinery's Handbook on the design of C-frame presses and was hoping someone might have a volume from which they can copy the relevant section. I think it was pp270-on in the 1922 edition... Should be no issues with copyright, as such a small amount of the book constitutes less that the 'fair study' provisions contained in most jurisdictions

 

Either post here or PM me if you can help please. Happy to share the build on this site once I get my head around the section sizes needed from the calcs. Considering a throat of 30-in, as that will reach to the centre of a standard sheet plus a bit on the short dimension. Yair, I know it will induce a rather large moment into the frame and that's the bit I need some theoretical data on; no point making a press that bends so far in use that it become useless, so the deflection needs to be kept to a minimum of course

 

As it is really re-inventing a well-spun wheel, is there anyone who has already done this style of press with this amount of force?

 

Regards

Jim Deering

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A friend of mine built a 40 ton C-frame punch with barely 6" of throat out of two sheets of 1.5" steel. You can see it spread when punching anything over .5" I think when you find out how think your plates will need to be you will come up with a tension design instead. Wild guess; two 6" plates will still spread (stealing your working energy), so yes, in my opinion you are re-inventing the wheel. 

 

I think it would be far cheaper to build a 60 inch wide H frame press, by several orders of magnitude. 

 

FYI; All works published in the United States before 1923 are in the public domain -- that is, not protected by copyright law.

 

http://www.nolo.com/legal-encyclopedia/copyright-basics-faq-29079-4.html

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Go check out Hoss Haley's web site. Or just google his name and shop tour, hydraulic press. He made a 40 ton c-throat  with a 24" inch depth of throat out of heavy c-channel, stoutly and selectively braced. He does cold forming of 3/8 plate with very large dies, with out failure. He also has a hundred ton h- frame he built, using a small (3-4") cylinder, generating the tonnage through a very simple ( and very stoutly built) lever system. This to is relatively well documented via google searches. I have a copy of that machinery's handbook, but I have a terrible time with uploading pictures, as that my phone is not (as of yet) smarter than I am. I might be inclined to transcribe the pertinent info  depending on how long the section is. Hope some of this helps, Take care, Matt

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I've been working on my website uploading pictures for the last two days, so I thought I might give it a shot here. I believe this is the info you seek from the machinery's handbook, also I have a fast acting hydraulic press with 14" of daylight and a 14" throat. That frame can be seen on the 35 ton c-throat press issues post. The frame is 2" plate boxed in. If you like I could take some more measurements. It's rated at 35 t acording to the mfg. but it has a 6" cylinder with a 7.5hp motor that generates over 5000psi if I let it ( I don't, the hoses aren't rated for it.) It also happens to be the same frame they use on their 75 ton model. All that being said It moves at about 5.5 in. a second so it actually has a bit of percussive force, and when I'm using it that way, It flexes a bit, but not in a scary type way. It also has a flair for the dramatic and flickers my lights upon impact.  

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I have a C frame 100tn. punch that's rated for 1" through 1" plate. The web of the frame is 2"+ the inside and outside flanges are 4"x 8" and it's a 1 piece casting.

 

Are you certified to weld heavy section? You might, just MIGHT get away with a heavy section box frame but I wouldn't put any money on it. Forget the preinvented wheels, this is a dangerous thing to play with, a failure could cost you more than money can buy.

 

Frosty The Lucky.

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Steve- The press has a very complicated set of electronics associated with it that included a electronically actuated digital pressure solenoid. I had to disable that to get the limit switches to do what I needed. It definitely has a mechanical blowoff but I've yet to hear it work. I've only used this press for a little bit of forging, and a bit more of forming, so I'm just careful about my pressures. I have plans to rip out all the electrics and simplify everything, and figure out how to adjust the manual relief down to a safe pressure, but as of yet I haven't had the time, nor the job to justify it. The biggest issue is the reliability if the solenoids. I've been through 3 of them. I'm just not sure what type to buy from msc. I talked to a fellow from parker, and they tried to recommend a $350 switch, but that seems excessive to me, but a couple more of these switches and my "seems like" becomes false economy.

 

Frosty- It seems to me cast iron would make a terrible c-style press frame due to it's inherent weakness in tension. I know industry has done it forever but I believe that to be on account of economy.I'm not sure what the corollary in steel would look like.  Most of the nice newer c-style press frames I've seen are fabbed out of plate/ c sections, and failure would consitute the bending of the frame, no? It seems like steel would would get pretty obvious  about its grievances before it gave way? In any case interesting to think about. Take care, Matt

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Got it. I'm comfortable with manual relief valves but will be dealing with pressure switches and accumulators soon for a press I'm re-working   I just re-built my old (80's) 40 ton hydraulic ironworker that had one of those Williams units with a piston pump built into the tank. The thing was noisy as heck and had pretty much given up the ghost.  I went with an external gear pump but had to add a manual relief valve to the tank. Not bad- 49$ for one from Northern.  Couldn't believe it when we fired it up yesterday- the new pump just purrs and could hardly tell the thing was on. All my power is back and then some!

 

I built a deep throat C-frame rivet press lately for a job. I used 1 1/4" A514 which is a 100000 psi steel; weldable with preheat from everything including 7018 to 11018.  I figured it would be stiff but with a 30" throat and about 20 ton of pressure I could not detect any deflection in the frame. I would highly recommend burning some profiles of your press from this stuff.  Yes- you do need good welding pre-post heat and DRY electrodes but I would do it again in a heartbeat. I really think it could handle 2X the tonnage with ease. 

 

What's unique is I scanned a 100 year old google image of a press into CAD for my model and scaled the trace down from 11' tall to about 4'.  When I finally did some measuring on the model I discovered something very revealing: the deepest part of the throat, the base of the C was just forward of the neutral axis.   Take a look at old presses and you may come to the same conclusion. Old manufacturers may not have had finite element analysis to look at stresses but they did have 100 years of empirical knowledge to see what worked and didn't.

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This is a photo of our 200ton davy press as it was installed at BHP Newcastle steelworks, if you need I can take some dimensions so as you can scale to your size.

 

Phil

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i think your 400  has more stroke an power  , but  this 200 it look impressive 

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I’d suggest you do this the old fashion way rather than speculate. Figure out what kind of force you'd like to apply and how much deflection you’ll allow and then calculate the structure. All the formulas are readily available on line. You need to know young's modulus 29 X 10E6 for A36 steel, the Moment of Inertia, (have someone calculate it after you decide a structure design if you can’t) plug this in to a beam calculator like engineers edge and walla. If you construct it correctly, which is a big IF, pre-heating the material, gouging the intersections of the welds, using multiple passes with heavy inter-shield wire, or the correct rod...bla..bla bla. You will surpass your deflection desired before it would ever fail “break” on you….most likely. You’ll be very surprised at how much deflection you get, from very little cantilever at the forces you are wishing to apply.

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Since youngs modulus doesn't change significantly between a36 and a514, do you think using the a514 helped, steve? That's a genuine question, I know you do a bunch of NDT/inspection.

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EF I'm not sure you are directing your question to me. If you are, just to clarify I don't do any NDT/inspections or anything like that or ever have. I'm a lowly metal worker/machinist/artist/blacksmith.  I'm not an engineer either. I have been in the business of building equipment all my life however.

 

To answer your material question; No I don't think there was an advantage to using a514 material over a36 because as you stated the "E" is about the same and deflection, or a minimizing it is the goal, not pushing the deflection to the point of failure " plastic deformation" or yield, where the a514 would be of value. Perhaps a well educated and experienced engineer will chime in here, educate all of us and tell me if I'm wrong, which could be.  

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Don't guess as to what is required. Get James Batson's "Build Your Own Hydraulic Forging Press". Blue Moon Press sells it. It has plans for C and H frame presses and charts to show you what goes with what and safely.

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I just received a copy of the book mentioned above by Randy and think its very well done. Complete plans with detailed drawings, BOM of the hydraulic system and explanation of how and why it all works. I'm guessing the cost will be higher that whats shown, from 10 years ago when this was published. The only thing I see that I would change, for what I do is redesign the anvil support to allow a long drift to pass through the anvil for making holes in bars or hammers. Other than that, if you need a 24 ton press with a short throat its looks like a good document to help you build one.

 

If however you want to build a beast with a 30" throat, as Jim Derring who started this post is looking for, this will be of no help at all really. A little rule of thumb to keep in mind when designing structures like this is the Deflection is highly dependent on length of beam element. For a given total load and distribution, deflection varies with the cube (third power) of span length. Therefore, if length of beam is doubled, deflection increases by a factor of 8, which is 2 cubed (2^3).
Even if beam length is increased by only 10 percent, deflection increases by 33 percent. thats significant, yes indeed!

 

 Thanks for the suggestion  on the book Randy! 

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Well, this thing has taken on a life of its own, as these things tend to do

 

Now grown to a bed press of 10'x 6' working area and 4' of clear space between the underside of the cross head and the bed surface to provide clearance for tooling and materials

 

Hydraulic motors and chain drives to provide controlled X and Y axis movement over this area - an area large enough to cover an entire 4'x 8' sheet of material - and probably long stroke rams to lift and lower the crosshead carrying the 40T ram, unless the motor and chain drive can be made to work here too

 

Also looking to mount a hydraulic drive and steering wheel at one end - three wheels all up - so it can be moved about the workshop under its own steam, or oil, if you prefer

 

Rudimentary calcs to get basic sizing are starting and might even get a CAD model out in a little while, after the calcs are past round one. Not a pipe dream either, as this is just the sort of thing you can fab up in the back shed in the wet season. Really!

 

More in a bit...

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