loktr2002

Hydraulic press questions

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Why is the speed of the press so important?  I keep reading references to faster presses doing more work than slower presses with more pressure.  I can see the dies pulling heat on thinner steel a detriment but on 1-2" steel it does not seem like it would matter that much.

Do people who have presses actuated by hydraulic hand valves typically use full pressure till bypass or feather the valve?  I am asking because I am looking at the positives of an electric 4 way valve and it seems that the downside would be that you cannot feather it.  I am planning to use the press for primarily damascus billets.

I have scrounged a less than perfect cylinder off a embossing press.  It has a 2.25 stroke,  A 4" piston with a 3 threaded bore (depth of threaded bore 3.5" )  i haven't disassembled the cylinder but I am guessing 5.5" bore.  I have been thinking that could work as it is unlikely to be able to reduce thickness over 1.5" per heat. What are the downsides of such a short stroke other than having to adjust for various tooling?

Ben

 

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How many gallons per minute does your pump put out? And at what pressure?

 

You have to design it as a system, not as individual pieces. It all has to work together, or it will just be a bunch of mismatched parts. 

 

Edited by BIGGUNDOCTOR

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If you are going to use a 2.25" stroke, you are restricting what you can do. You can't do much!!

If you are going to go to the expense of making a Press, make one that won't be so restrictive. You have no idea of what you want to do, leave the window of opportunity OPEN!! Don't cramp your thinking, by thinking you are saving money. YOU AREN"T when you will have to throw it away and start again later!!

Learn how to use Hand Tools first. Machinery will be very frustrating, when it does something that you didn't want to it do. Start off with a small scrap pile, instead of a huge pile of mistakes and possibly gaining some physical impairment (that may last your life-time). Machinery can hurt and it won't care how you feel!!

Find someone near you who you can ask to teach/borrow/use, so you can figure out what I am talking about. By going slow, it will save your mistakes!!

Neil

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Thank you for your cautions.  However i have been building machines for 40 years and rebuilding them professionally for 25.  While building a  a press does not intimidate me, building one without as much knowledge as i can garner does.  Both from the standpoint of wasting time and unconsidered hazards.  I personally think that mechanical power hammers are much scarier..

I have several power packs ranging from 1 to 10 hp but none of them use the 2 speed pumps suggested by Batson.   I asked about the need for speed because I would prefer to keep the hp to 7.5 or less (like to run it at home off a 10 hp rpc)  and i don't think I can do that without a two speed pump or a smaller diameter cylinder.  I am aware of the need to match components but am asking for the reasons (speed).  I am speculating (as I dont have the experience) that if hp were not a consideration that a single stage pump would be just as good as a two stage.

While i do have a limited amount of knowledge about how others use/operate their presses I have educated myself with the Batson pamphlet, Randy McDaniels book (I thought this was just great!) and the Parker series on control valves.

What i was asking for was information on the actual operation of forging presses so I can determine whether to use a solenoid to operate the cylinder or whether a manual valve would work better.  I want opinions

I have a horizontal press that uses a variable output pump and a hand valve.  I use this for bending components cold.  I do feather the valve as I dont want stock flying at high speed.  I have felt that this press would benefit from a diverter valve so that i could precisely stop bending without depending on a die to stop the bend.

Your advice Neil about finding someone near me is great.  Anybody in the Chicago Northern Il. area who would be willing to show me their press?

Neil the reason i asked about the stroke was my reservations about  limiting the application or ease of application about what seems to be the perfect cylinder except for stroke.

Thanks,

Ben

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I was going to build a press using solenoids and limit switches as I was an industrial maintenance man and was used to them. But when I went full time  I bought a ready to run press from http://www.oldworldanvils.com/hydraulic_presses/index.html   He uses what looks to me to be a log splitter style manual valve on a treadle. I'm glad I didn't build one my way. With this setup I can bring the press down at full speed, stop it any where I want, gently touch the stock or apply full tonnage just by pressing the treadle down. I like the  speed so I can get to the hot metal faster. I also have an adjustment to only lift as high as needed before it stops the upward travel. No need to full stroke the cylinder. My press is in the back of Randy's book with some of my tooling. And my daughter running it.

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One of the situations where:  Just because you can, does that mean you should???  And personal experience trumps theoretical knowledge every time...  :-)  I don't have time to do all of the cool things, I could do... So I have to pick and choose the things that I NEED to do myself, and the things that I really want to do myself...

Edited by SJS

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Press speed is usually important in that the dies suck heat out of the billet. So a press that moves faster when actually pushing the work lets more work per heat occur.

Two speed pumps are great to get the press down to the work, and then limit the Hp draw when at pressure. The Hp demand is usually pretty low in two speed mode as most have a 500 psi limit and then the bigger pump bypasses letting the small flow pump make the working flow/pressure.

A great source for valving and pumps and bell housings etc is Baily sales in Knoxville Tn. 1-800-800-1810

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