# Largest iron worker?



## Janger (Jun 30, 2022)

I was reading @PeterT ad for his iron worker that will punch a 1” hole through 5/16 material. That got me thinking what is the maximum size hole with maximum thickness possible? Is there an upper limit to this process? I can’t understand exactly how a punch could make a large hole through thick material and it still turns out with clean edges and not torn. 

Practically speaking the largest one I found with just a casual search is the 180 ton jmt USA model which will punch a 2.25” hole through 1” thick steel. The machine looks huge. 



			http://jmtusa.com/wp-content/uploads/2015/10/JMT-IW-165-Ironworker.png
		










						180 Ton Ironworker | JMTUSA.com
					

The JMT-IW 165 ironworker is the powerhouse among JMT's dual cylinder machines. With a punching pressure of 182 tons it has the capacity to put a 2-1/4




					jmtusa.com


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## johnnielsen (Jun 30, 2022)

Hole size minimum with standard strippers/hold downs is hole diameter equals plate thickness  as in 1/2" hole through 1/2" inch plate. Smaller holes can be punched with the use of extraordinary stripper/hold downs and punch supports.

I haven't heard of a limit to hole diameter through a steel plate but the greatest thickness allowed on my online calculator is 1.250".

I have seen 6 inch holes punched in 5/8 steel plate. Very loud.


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## phaxtris (Jun 30, 2022)

Most of the units I have seen in general fab shops are typically limited by the lower die for hole size, usually around the 1 1/8 through 1 1/8 material, the guards and lower die holder seem to be the limiting factor. I've used a range from 40-140t and they all seem to max out at 1 1/8 hole from what I remember (the thickness of course varies for the tonnage)

I'm sure they make larger capable machines, I'm not sure how popular they are...especially now with CNC equipment becoming more popular 

From my experience the thicker the plate the quieter the punch/shear is doing it's thing...figure that one out

You want to hear noise....I worked at a shop that had 2 NC turret punches, an operator would load in a part, sometimes the size of a 4x8 sheet, and this thing would slam out holes, slots and louvers at like 60 punches per minute....

Or I once witnessed a guy punch a hole through a 1/2 piece of plate that turned out to be ar500...or hardox, no one was sure but it sounded like a bomb went off


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