due to a pending rewind, heres what the core of a terroidal transformer looks like.
its a steel band wound in a tight spiral, held togeather by a seam weld and plastic end caps.
oh the temptation to cut that band seam, leave it on a hot plate and watch the fun unravel 
oh the temptation to cut that band seam, leave it on a hot plate and watch the fun unravel
BOI-OI-OING!
And if you want to see how it all goes back on, here’s a video. I chose a big toroid so the technique would be easier to see. About the right size for a serious power amp, or a 2Hz cross over choke.
yup, i know those machines.. they are awesome.
i spent YEARS puzzled trying to figure out how they wind the things;
then i became good friends with a veteran of the amplifier industry, the owner of matrix amplifiers who makes everything from the casework down to the transformers.
hes switched over to properly engineered switch mode power supplys now tho.
this also impresses me; tho more people will have seen this by now.
cutting a (mockup ?) v8 engine block out of a solid lump of ally with a 5 axis cnc:
precision fly cutting an engine:
im not much of a petrol head (abit of a biker tho), tho this still fascinates me.
ah, heavy duty engineering
cutting a (mockup ?) v8 engine block out of a solid lump of ally with a 5 axis cnc:
Ho-ly crap. That is awesomeness in pure aluminium. 4:27 for teh win, with the shards of hot alu flyin at the camera 
About the right size for a serious power amp, or a 2Hz cross over choke.
I think that a poorly designed crossover is probably what went wrong in Doc Brown’s Lab.
(ca 3:22 if anyone has still managed to not see this film…)
