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I Forge Iron

Press design critique

Brian Evans

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First off I am prepared to get a lot of negative feedback on this design as it is to be made out of wood mostly. Safety is the number 1 concern and I don't want to jump into anything I am not prepared for. I am planning on using a 10 ton pneumatic bottle jack as the power. From my research to the tensile strength of 4x4 pine ( I was not able to find much) told me that a 6 ft long piece has a constant load bearing of just under 1000 lbs when hung from the middle. This design is estimated to be 3 foot wide by 5 ft tall, and there is supposed to be an even distribution of pressure along the beams.

Any input is appreciated.

Hydrolic press.png

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What is it that you want it to do? Can't evaluate it without knowing what it's supposed to accomplish.  Certainly not for forging as a hand actuated bottle jack is way too slow.  Bending clips for collars would probably work.

Considering that you could bolt a steel frame together---why go with wood?

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6 minutes ago, ThomasPowers said:


I wanted to be able to upset some of the larger pieces of metal that I have into a more workable billet. Also would like to try my hand at pattern welding. I would be using a pneumatic bottle jack so it should be quick and hands free as far as controlling the press (foot pedal).

As far as making it with wood it is what I have available at the moment. I don't have any beams or frames.

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Whats the speed?  How big a piece do you plan to upset?

If you wanted to cook dinner but all you had to hand were inedible materials; would you cook dinner with them or would you source food? 

What is the failure mode of wood? (especially pressure treated pine!)

I'm glad you are prepared for negative comments as I do not think your design will work for what you want it to do.  I am a big proponent of people using known good designs until they have the experience to start making changes to them.

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4 hours ago, ThomasPowers said:


4 inch diameter (ish) of high carbon steel is what I have currently. I am not sure about the speed of the pneumatic jack but I would assume it would have to do with the air compressor psi which is 150.

Are you trying to say that wood is useless in this application?

I am not sure about exact number for the failure mode of wood but it has to do with the number of knots in the wood. I was planning on making sure that I didn't use wood that was too knotty.

I have been considering buying a press new (as I cannot find any within driving distance used), but I don't really have 400$ to drop at the moment. If you don't think that making it out of wood is a good or safe idea then I guess ill have to sell a lot more hooks and bottle openers.

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8 hours ago, jeremy k said:

Please don't forget to post the video, you might be on to something.

Hopefully not a Darwin award...  Any hydraulic press that is intended to squeeze steel in the 2,000 deg. range can be dangerous and should be designed by someone with a better understanding of engineering (for example the tensile strength of the wood is only applicable in your uprights, a slight bit of misalignment will also cause a moment stress on your joints, but I'm only a mechanical engineer with very little structural training.  I would go to someone with a lot more background in structure to evaluate this)

Seriously I would do a lot more research and likely head back to the drawing board.  There have been air over hydraulic presses made (small metal ones), but the typical feedback is that they are too slow for efficient forging operation.  Here you are adding another suboptimal choice of materials to your design.  Wood can fail in bending, tension, compression and twist.  Potential issues I see with the soft pine wood include:

  1. Off center moment forces putting forces on the joints that you don't expect
  2. Failure of the attachment points between the wood uprights and cross members
  3. Localized compression of the wood at the corners of the metal distribution plates where the wood cross member will bend and the metal plate will not leading to failure points
  4. Slow press operation allowing the hot stock to overheat the metal distribution plates and burn the wood.
  5. Differential expansion of the wood due to humidity leading to potential racking of the configuration and binding of the moving cross member
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Sorry I was being sarcastic. I built a 24 ton press frame with "steel" and I have used it to make spring swage blanks from mild steel that are 1" thick and 2-1/2" square - even at a good heat it takes 2-3 heats to get the final shape I needed squeezed into them. Upsetting a 4" high carbon round would take a considerable more amount of a press to achieve a good upset on 4". 

Building a press from wood to do what you are wanting to do, in my opinion would be "upsetting" at the very least.

Steel is your friend. Good luck

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Yeah, safety should be the number I priority. I think I'll have to wait and save my money to either buy a welder and take some classes or buy a commercially made press. 

Thanks guys, I hope I didn't sound like too much of a fool for posting this design. 

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