Ironworker Blade Design Help

For those of you who do not know, I’ve been hard at work on the design of the open source Ironworker Prototype II and plan on building it this winter at my grandfather’s fabrication shop, Enniss Inc. I’m calling out to fellow fabricators and engineers to help with the Ironworker design, so we can place the design of this very important tool into the repository of common knowledge. For those of you not familiar with the importance of an ironworker machine – it is the heart of any custom metal fabrication shop – a shop that can build any of the mechanical devices of the Global Village Construction Set.

This prototype will be the second version of the Ironworker. As well as having the 120T punch, this prototype will be able to shear 1”x12” flat and 6”x6”x1/2” angle steel. There will be a “tool cavity,” a space below the punching arm to which many accessory tools can attach. This will enable the machine to not only have the features above, but also attachments like brakes, notchers, and rod shears.

Scotchman 120T Ironworker

Scotchman 120T Ironworker

I had another design nearly developed using a vertical shear, but trashed it when I realized how much better it could be with optional attachments. And now, I’m stuck.

The first design version (1.0) of Prototype II

I need help designing the lower arm and flat shear. Because the cylinder will be attaching to both the upper and lower arms, the simplest way for the blade to cut will be angularly, meaning it will be rotating about the pin. For an angular cut, I’ll need to know:

  • How much force is necessary for this capacity
  • What angle the blade will enter and leave the steel
  • Where the blade will need to be vertically on the lower arm with relation to the cutting table.
  • How thick the blade needs to be

One solution would be to find another ironworker and reverse-engineer the shear. If I can get the dimensions of the shearing arm on another 120 ton ironworker, I can derive the necessary force for shearing 1” x 12”, and imitate the blade placement.

The other option would be to find the necessary force and force placement via CAE analysis. If it helps, I know that it requires 120T applied vertically with a 6° blade rake to shear the 1”x12”.

The last thing I need is to know the necessary blade thickness.  If I find the thickness for the flat shear or angle blade, we will build our own blades by machining tool steel and getting it professionally hardened. If we can’t find the info, we will have to buy the blades and then copy them for a future prototype.  We have smaller capacity ironworkers at my grandfather’s shop, with a 1”x6” capacity, and 2 like this both have .75” thick blades. I’m not sure if the thickness would increase or not for a 12” cut.

My basic design will be done soon after I get this information, and then we will have it analyzed with CAE to make sure it will work.  My goal is to be able to start fabricating it by Christmas, with the prototype completed and documented by the end of January.

If any readers have access to another 120T ironworker, any of the blades, or know someone capable of doing the computer analysis, please contact me: Brianna (at) kufadesigns (dot) com. Also, if you have any good design ideas, don’t be afraid to contribute on the wiki page.

Worst case scenario, if I can’t find this info, I can make the blade move vertically, but this would require much more steel and a more complicated design, so this should be avoided if possible.

Thanks for your help,

Brianna Kufa


  1. […] contributions as project proposals and bids for remote prototyping and development – whether directly on GVCS 50 development, resource development, documentation, design challenges, or many other […]

  2. […] Ironworker shear assembly challenge is now live at GrabCAD. See my prior post here, and note that we are funded to get this done. Let any engineer friends […]

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