October 21, 20178 yr In a recent YouTube video about grinding a khopesh, the smith mentioned that the blade had had a slight bend near the tip. Rather than hammering it, he heated the workpiece and laid it on the magnetic chuck of his surface grinder and engaged the electromagnet. It sucked the blade flat to the surface of the chuck, et voila! A perfectly straight blade. This seems like it could be a useful technique, especially for long blades, or ones with unusual shapes (and stresses), though one wonders why it isn't more common if it's so useful. Additionally, I could see how the magnetic field might impart some unusual stresses to the blade, though I can't imagine they'd be nearly so strong as the ones imparted by the hammer. I resolved to petition the community for their consideration... So, any thoughts?
October 21, 20178 yr Author If someone else knows the video I'm referencing, feel free. I'll have to wait another 5 or 6 hours until I get home from work; the computers here won't access YouTube, and my phone's dead. The channel is "Hoffman Blacksmithing," but you don't get to see it happen on-screen; he just explains what he did.
October 21, 20178 yr If the steel is hot enough to be bent with such little force wouldn't it be non magnetic?
October 21, 20178 yr Author If it's above the critical point, sure, but I don't generally get it that hot for a little straightening. In the video, he's already done the profile grind and started working on the bevels when he mentions straightening the blade. At that point in the process, I'd be too scared of burning an edge to get it back up to austenite temperatures. Besides, a good electromagnet can generate a considerable amount of force. One strong enough for a chuck on a surface grinder is more than strong enough, I'd imagine.
October 23, 20178 yr Why invest in a whole nother tool when the hammer and the anvil work so cheaply and well? Use a wooden hammer if you are worried about marring the surface of the blade. (Or as it's known in my shop the "stinky hammer" a rawhide mallet.)
October 23, 20178 yr I've often used a magnetic chuck to flatten shim stock, ... but never anything heavier. .
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