MAGNET
BODY (includes individual drawings of the 4 poles and the 2 pole spacers):
In the past most commercial magnetic folders have been
manufactured by milling the magnet body from a solid block of
steel, usually 100 x
50mm.
However a much easier way to manufacture it, especially for a one-off,
is to fabricate it from steel sections.
The method outlined here has only recently been tried and was found to
work well.
Only 2 plain sections of steel are required:
Section 1: 50 x 16mm, or 2" x 5/8"
Section 2: 19.05mm or 3/4" square.
It is strongly recommended to obtain
cold rolled steel,
also known as "Bright Mild Steel" (BMS).
BMS has a nice smooth finish, and is free of mill scale.
Also BMS is straighter and more accurately sized than hot rolled steel.
BMS does cost about 50% more but is well worth it for
constructing this type of machine.
Alternatively hot rolled steel
can be used but it
will require some finish milling after assembly.
The
BMS sections above are used for the magnet body components below and also for the Bending Beam, Clamp Bar, and Bending Beam Extension.
BMS is usually supplied in 3.5metre lengths.
One length of section 1 will supply enough material for the four magnet
poles. ( That leaves enough for the bending beam as well.)
One length of section 2 will make the two pole spacers. (That
leaves enough for the bending beam extension piece and there will be
about 1.5m left over.)
To cut the steel to length a
cold saw is
recommended, although your steel supplier may pre-cut it for you.
For this design all pieces of steel for the magnet body are cut to the
same length -
620mm.
(But for the
Bending Beam, the Beam Extension and the
Clampbar the lengths are
670mm
long.
If the main clampbar is to have milled finger grips then it will need to be cut to
690mm long).
First cut 4 pole pieces and then drill and tap the various holes
required . (
Refer to drawings below).
You will also need to mill 2 rebates in the front pole to accommodate
the "
Hemi-Hinge".
The 2 middle poles will need the corners chamfering to make sure that
the coil insulation will not get damaged during assembly of the magnet
coil.
Also cut 2 pole spacers to 620mm long and drill the clearance holes for the assembly screws.
All these pieces can now be assembled and bolted together using 4 off
M8 x 90mm socket head cap screws as shown:
Before final tightening of the screws, place the magnet body upsidedown
on a flat surface.
When the screws are tightened this should guarantee a nice flush upper
surface for the magnet body.
Parts Identification:
Drawings for all these parts will be found below, starting with the Front Pole and progressing to the Rear Pole.
Pole, Front drawing (Click drawing to enlarge):
Pole Spacer, Front drawing (Click drawing to enlarge):
Pole, Middle-Front drawing (Click drawing to enlarge):
Pole, Middle-Rear drawing (Click drawing to enlarge):
Pole Spacer, Rear drawing (Click drawing to enlarge):
Pole, Rear drawing (Click drawing to enlarge):
"Handyman" Index page.
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Magnabend
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