Question about Hydraulic Presses | OK, Here Are The Rules | Forum

Specifically for pattern welded steels, a fast cycling press is more advantageous than a larger tonnage moving at a slower ram speed. One inch per second of ram speed is a good generally achievable average speed. For a 25 ton press, a 16 gallon per minute pump running at 3500 rpm in a five or six inch cylinder is a good general calculation. Two stage pumps are better for beginners/classrooms, single stage pumps will squeeze things down to sheet metal if you're not paying attention, but for the more experienced operator will get more work done.

The reason for recommending a fast cycle time, is that you have a limited window of time to achieve your welding, heat drops as soon as you leave the fire, and once the billet comes into contact with your tup/sow dies the heat sink begins, further shortening the window of time to achieve your welds. You want to get on the billet and off again quickly so you can move to the next segment of the billet and get on and off etc., welding as much as possible in one heat.

The oft discussed advantage of the press over the power hammer is that the billet material tends to move from the center of the billet outward helping close up any voids left in the billet assembly. This rule generally holds true especially for the more common lighter weight power hammers which tend to move surface material more than internal. You could seal the billet around the outside and leave a largish void in the center and think it was all welded until you start to see bubbles. Up in the 250 weight or greater power hammer range this does not hold true.

It's all about reducing scrap rate anyway. Presses have their purposes. It's best to think of them as big slow hammers and use them the same way. If I could only have one tool, I couldn't live without the hammer, a press is nice and a rolling mill is gravy.

Neil Gustafson;17169 wrote: ...Try one before you spend your wallet. Wait for your class, to find out what works.

I would reinforce that idea as well. Visit some shops and get some time on the tools. Find different setups and try each of those. Listen to the owners, especially when they explain why they built what they did, then what they would change since they built it that way. Tools like this are the accumulation of experience.

I remember, in the Midwest anyway, when Hank Knickmeyer's log splitter was the first one I knew about. The ideal press has been heavily modified since then as new ideas come down the pike.