This continues to amaze me. I had tested with 207 lbs, then set up a
better test rig and added 85 lbs more (292 total) - no problem, 52 more,
to 345 - no problem, then 393 (48 more) - still holding!! But at 425,
my engine hoist bent! It was homemade, by the that-looks-about-right
method, so perhaps to be expected.

Back to the drawing board, as they say. Then inspiration: use 2 equal
pole pieces & just load one. I.e., I would be measuring 1/2 the pull.
So I got another 3/4" bar and used each of the 2 bars to cover 1/2 of
the pole area (the long way) and fastened the load to one of them.

I backed off the load, some, to 369 and it _just_ lifted it before
letting go. I had _finally_ found the limit. That means that this
little MOT electromagnet is capable of holding 740 lbs! WHOA! Double WHOA!

The coil is 3-3/4", i.e., in a magnetic brake it would take 3-3/4" of
clamp space. And the magnetic pull rate would be 740 divided by that,
or about 200 lbs/in. Compared to the 250 lbs/in of the MagnaBend. Now,
if it isn't saturating at 120v & could be run higher, with more flux,
and more pull, we could be in the DIY magnetic brake business.

Some tidbits: it's not easy finding a 400 lb load - I had 2 milk crates
FULL of MOTs, lead ingots, exercise weights, chunky steel stock, and a
lathe tailstock. It's also not easy lifting that much - I was using a
come-along & doing one click at a time.

At the 345 level, I tried something. I backed off the coil voltage (I
was using a variac) until it released the load. It was at the 30/100
mark. 36 volts if I hadn't wired in the boost section of the variac. I
don't know if this means that the core runs saturated at 120v, or what.
But I intend to find out. It would be much better if it didn't have
to run at 120v.

An aw-**** moment: when the magnet did let go, a piece of lift chain
smashed into the coil & cut through a couple of turns. It still works,
but probably not for long. But I have 2 other MOT electromagnets, and
8-10 untouched MOTs.

Stay tuned,
Bob