Sparks would only fly if connections were made with the system energized. You're probably limited to what, 0.5 - 1 volt across your "shorted" turn (however many volts / turn that transformer has, which at a fixed frequency will be a function of core area and Bsat). That's going to make things hot, but it probably won't blow it up.
There are lots of ways to mount a toroid - you just can't form a shorted turn. Putting a square metal plate on top of it with a bolt on each corner is one method that I sometimes see in applications where mechanical robustness is a concern, since a single large bolt in the middle could conceivably tear the sheet metal chassis more easily. It also saves the need for a 12mm or larger bolt passing through a chassis, which is a real pain if it needs to be rackmounted.
Thank you all. kodabmx's picture did the trick. I was struggling to figure how the case and bolt
weren't already causing the short that kevinkr described initially. (only 1 rubber insulator disk was
included but I have rubber roofing material that will suit for the second insulator.)
weren't already causing the short that kevinkr described initially. (only 1 rubber insulator disk was
included but I have rubber roofing material that will suit for the second insulator.)
I measured that current once, not sure how accurate it was, but I recall in the vicinity of 100A at the higher power setting.
Since the bolt hole is in the middle of an epoxy plug in the center of the toroid, the rubber washer goes on the bottom to prevent the transformer from bottoming on the chassis and one isn't required on the top in this case.
Some toroids do use two rubber washers because there is a stamped metal plate that goes on top to center and secure the transformer to the chassis.