In the past most commercial magnetic folders have been
manufactured by milling the magnet body from a solid block of
steel, usually 100 x
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
Only 2 plain sections of steel are required:
: 50 x 16mm, or 2" x 5/8"
: 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.
BMS is usually supplied in 3.5metre lengths and just one length will
supply enough material for the whole magnet body and even the bending
beam as well. It should cost less than A$100 for the small
You will also need to obtain a 3.5m length of 19.05mm BMS square.
This will make the 2 pole spacers and also the Bending Beam
Extension piece. (There will be about 1.5m left over).
To cut the steel to length a cold saw
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 the Bending Beam, the Beam Extension and the Clampbar are 670mm
First cut 4 pole pieces and then drill and tap the various holes
required . (Refer to drawings).
You will also need to mill 2 rebates in the front pole to accommodate
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
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.
to "Handyman" Index page.