The above are surplus computer electronic assemblys
with chrome plated neodymium 4 pole magnets, precisely of the type I use
in my S-G type seismometer "Yellowstone". The
lower magnet is one disassembled unit (knocked off
from glue holding it too steel assembly). The age of these is a guess
of being made around the early 80's. With their 14K gauss field they
are the "worlds most powerful handgun (magnet)", in commercial production.
(IMAGE 1)
OK...I don't know the manufacturer, nor exactly what
they are off of...but I think a good guess is old computer main frame salvage,
perhaps of the late 1970's. They are samarium magnets with a ~ 12-13K
gauss field. I'll say...they are impossible to remove from the steel,
as I've tried, but ended up breaking them as they are very brittle.
This is the magnet that I use on my homebrew S-G type "Yellowstone" for
aluminum plate eddy current damping. (IMAGE 2)
Old (1960's?) H-P, Alnico poles with soft iron keeper.
Wild guess of gauss field...~ 800. The holes through the poles (Two
Black objects on gray iron...which are actually separate magnets in themselves)
can be bolted down to the keeper. The poles can be adjusted (slide)
via physical positioning. Low gauss, but their size makes for a big
broad field on coils. Originally these were penmotor magnets.
(IMAGE 3)
Another Hewlett-Packard old penmotor magnet of perhaps
the 1960's. One piece (one magnet), but with sliding soft iron "keepers",
which can be inverted to that shown. Gauss guess ~ 800. This
also has through the magnet holes. (IMAGE 4)
These look for all the world to be made by the same
unknown manufacturer which made the Image 2 magnets. Samarium, white
painted magnets with 12-13K gauss. Big difference here is that the
unit sides can be separated (adjusted) by simply putting spacers between
the yellow colored steel holders. Probably of the late 1970's.
(IMAGE 5)
Ohhhh....The Stars of Texas are upon you.....Texas
Instruments HUGE old penmotor magnet of around the 1950's origin.
Base bolt holes and also iron keepers/spacers on front top. This
dinky thing (ha) weights maybe 15 pounds. Alnico of maybe ~ 800 field
gauss. The soft iron keepers on top can be removed, or moved/adjusted
over the single magnet cast. (IMAGE 6)
Good old Esterline-Angus speed-servo penmotor assembly.
The center bright area holds a slab of ferrite, whose field influences
the moving linear coil at the front....and via a steel wrap around steel
structure through the round bar for the opposite field. Gauss field
through the coil guess is maybe 1500. (IMAGE 7)
Brush Instruments old penmotor Alnico assemblys of
perhaps the 1960's date. Traditional horseshoe shape. No mounting
bolt holes. Not to be underestimated, these also have
a gauss of some 800, and are single piece units. (IMAGE 8)
This concludes the tour folks.