I've been following this thread with interest, but not actually planning on
trying to build this type of machine.
I think that finding a way to get the 51" $375 Craigslist listing unit
delivered would be a worthwhile consideration..but I do understand the
curiousity of potentially being able to make a useful machine from salvaged
parts.

I was thinking that the primary windings may be better than the secondaries,
but you likely know better, and the number of turns on the secondary side is
much greater than the primary.

I haven't looked at a MOT in a long while, but cutting away a primary
winding (or either winding) from the E-core, I think that would leave more
room available for a custom wound bobbin that fills the entire E-core..
making a much stronger electromagnet.. so it would be a determination of
which is the best wire gage to use, and where to get a lot of it, then a
method of carefully winding the bobbin (flat, level layers for the highest
number of windings).
My local motor shop has lent out large spools of magnet wire in the past,
then they weigh the spool when it's returned and charge a very reasonable
fee for how much weight was removed.
If one had a significant number of identical MOTs, doubling either winding
onto the E-core may be possible.

A second aspect is the mating surfaces of the E-core sections of the core to
a separate piece of metal.
I'm thinking that the most effective coupling of the two surfaces would need
to be very precise for the most effective magnetic transfer to the steel
bar.. possibly a very close tolerance smooth/flat surface that a surface
grinder might provide.
Attachment of the E-cores could then be held securely to the steel bar by
tack welding the E-cores in position.

I believe that winding the coil to fit directly on the lower section bar
would be the best solution, for maximum efficiency.

--
WB
..........


"David Billington" wrote in message
...

Can you be certain the Australians were using AWG and not SWG, it makes a
difference. Their video mentions it bending "16 gauge" and their
specifications mention 16g/1.6mm which would indicate SWG is in use at
least for the metal specs, US metal gauges are thinner for the same
number.