> I remade these adjusted for shrinkage and with sprues already attached for lost PLA casting here: https://www.thingiverse.com/thing:3000701

A 3d model of a JD2 tube bender die. Dimensions from the prints available on:

www.chopperhandbook.com

Thinking about casting one with lost PLA in aluminum, but it will need adjusting for shrinkage and finish machining allowance if I do. I made it as accurately to the print as possible, so if this model is used for casting the OD will be too small, tube cradle too large, and holes too large. (Remember the metal will shrink in size, making all negative features larger as well as positive features smaller.) Also supports needed on the leg will mess up the surface so that will need allowances as well. May just redesign it to be two pieces that snap together before the investment dip. Still in early planning stages at this point.

I know the radius for the tube is a bit rough, limitation of TinkerCAD. For some reason this PC won't open any shape generators, was stuck with the basic shapes.

> Uploaded split die and pin. Concept here, has not been resized for casting. I don't even know how much to resize it, may just have to cast one and measure to see. Print one each of the die halves if you want to play with it, they aren't the same.

>> Added LPLA files. For lost PLA casting. The two 20mm holes not found on chopper handbook print are for the pins which hold the two halves of the print together. These have a 2% shrinkage allowance. All holes are undersized, radius for tubing is undersized enough that it should allow machining of any tube size down to 3/4". Castings will need to be machined. Suggest machining to thickness first, then bore all holes to size and location. Afterwards rotary table or custom jig on lathe with between centers boring bar can be used to machine tube cradle radius.

>>Added Green files. For greensand casting. These have no holes, no starter radius, simple blank. They don't have draft, but if you print with a good many walls you can sand some on. They're shallow so probably don't need any. These patterns can be permanent for many dies if printed dense enough to take the ramming. Tradeoff being more metal to fill mold and more metal to cut away when finish machining.