I've been having some difficulties hand working iron blooms. When cutting slag off of the bloom there's a number of voxels that are on the base layer that are outside of the dimensions of the bar, and using the Shift key to add a partially worked bloom to another to get more voxels to fill the gaps does not add material, unless there's a special trick to it. Reheating the bloom will also sometimes change the orientation of the ingot outline by 90 degrees, invalidating the base layer I had previously worked.
Are there tricks to working iron? Is it effectively helvehammer only?
*edit*
After experimentation, Iron working does indeed require the helvehammer. You can work it by hand, but the voxels will never be right. However the helvehammer adds the missing voxels rather than move them around. It was a race to keep it fed, so I made two forges and had blooms in continuous heat up mode. I ended up knocking the slag off the blooms, by which time the helvehammer had nearly finished the main block, so I simply ended up splitting off the excess before the hammer could. A stormy night really makes it fly.