I've found steel-framed benches to be very easy to make using only a concrete
floor and firebricks as 'tooling'. The general procedure goes something like
this:
1. Obtain material. Benches are often needed for special purposes and are
usually made from whatever happens to be on hand so the first chore is
digging through the shop or behind the shed to find the right stuff.
2. Cut material to length. Knowing the height, width and length required,
here is where things get shuffled around so as to arrive at a symmetrical
assemblage -- all legs of the same stock, for example. Looks a little nicer
that way.
3. Clean for welding. The stuff is always rusty. Sandblasting takes care
of that and leaves a good surface for both weld and paint.
4. Lay out & tack-weld legs. This is done on a level concrete floor using
firebricks to hold the pieces in position. Some experience with welding is
required since some allowances must be made for expansion. Properly done,
the welds will balance one another and you'll end up with a square structure
without a lot of internal stress in the welds. I've found I get a more
accurate finished produce by doing the front/rear legs as pairs.
5. Position tack-welded legs and tack-weld traverse members between them.
Again, this is done on the floor. A clamped Z or X brace comes in handy to
keep things straight while tacking the traverse members that can not lay on
the floor.
6. Stand the bench on its legs and adjust any errors. They never come out
perfectly flat the first time. This step is where I install whatever makes
up the feet or leg-column bottom closure. The object here is to arrive at a
level upper structure with all of the feet flat on the floor.
7. Install detail work. That includes cross pieces or diagonals, hinges and
racks, and any doublers needed to support a vise or other tool that will be
installed on the bench, including the bench-top itself if other-than steel.
8. Finish-weld. It's a good idea to distribute the heat when doing the
final welds so as to minimize any distortion. If the bench is to have a
steel top and if the top is 1/4" or less, it's easiest to put the top
material on the floor and postion the bench on it, doing the stitch-welds
while up-side down.
9. Paint. Rustoleum, sprayed or brushed, has provided 20+ years of
protection for steel tooling and benches here in southern California about 5
miles from the sea. When dealing with a sandblasted surface you should them
painted as soon as practical, even to giving the material a spritz of paint
before the finish welding, if the job is going to take more than a few hours.
Once sandblasted, steel develops rust at an alarming rate due to its greater
surface area.
Besides their excellent strength to weight and ease of fabrication, the main
advantage of steel benches is fire prevention, followed by dimensional
stability. Steel is the most practical material for supporting your surface
plate and for any tooling. Welded steel structures are the most practical
when high strength is needed.
-Bob
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