DoN. Nichols wrote:
I suspect that the magnet is a continuous stack of E-cores the
full active width of the brake -- all in a single coil. If you had a
bunch of MOT cores, you would have areas where the grip was a lot weaker
than you need.

It's true that the field would be uneven. My test magnet, for instance,
has coil width of 3.75" & a core width of 2.25". 40% of the length
would be field-less, more or less. However, if the average field/grip
is the same, the 4 x 5/8" clamping bar should be beefy enough to provide
grip in the field-less areas. In other words, if the total clamping
force is the same, the clamping bar should spread it out evenly (enough).

Bob