On Thu, 03 Feb 2011 22:51:36 -0800, Winston wrote:
DoN. Nichols wrote:
On 2011-02-04, Winston wrote:
....
Followup question: Would that affect the ability of the magnets to
attract the clamping bar, for better or worse?

It would weaken the clamping attraction in that area I believe.
If I were making a long electromagnet using Microwave Oven
Transformers, I would probably strip off the windings entirely, butt
the cores against each other as follows (letters are core identifiers,
'+' are outer poles, '-' are inner poles, three cores shown here, but I
would use as many as needed for the length to be covered:

[snip ascii graphic]

Not as much fun as designing that coil winding machine!

I'm getting a headache trying to think of a way to make that inductor
more than one layer deep.
....

Suppose you wanted about 20 layers of wire. Get 20 rolls of wire,
and run a flat layer of 20 at once, weaving in and out from left end
to right end of stack of cores, then back from right end to left end,
etc. Probably not easy to do automatically or well.

--
jiw