On 20 Jan 2007 23:56:14 -0800, "
wrote:

Prometheus

Yes I am aware of those saws and have used them, but in the maintenance
shop though we used upright band saws that you used to saw hand held
pieces, and used those blades with a high number of teeth, but I got
trained a long time ago with power hacksaws and you certainly would not
put any course tooth blade in for sawing pipes or other thin stuff, as
the teeth would be ripped right out the blade, that's where the 3 teeth
minimum in the material was taken as a rule of thumb, all those saws
where gravity saws, where a sliding weight was used to put more or less
pressure on the blade,

You know, I've never actually seen a power hacksaw in action, though
I've thought about trying to make something of the sort from time to
time, as a less expensive option than a bandsaw for pipe and angle
iron cutting, and less labor-intensive option than hand sawing (my
current method.) Would I be far off the mark in assuming that they
operate with a reciprocal action by attaching each end of the blade to
a cam wheel, with the downstroke applying the cutting force and
forward momentum, and the upstroke pulling the blade up and back? Did
they swivel on a single pivot, or ride on a pair of posts?

Far as the thin stuff goes, you are of course correct- the corse tooth
counts are for thicker material. There was a rule of thumb for blade
selection, though I am not sure that I can remember it correctly any
more- IIRC, 2-3 was for thicknesses greater than 1", 3-4 was for
..375"-1", and a finer tooth count was called for with anything
thinner. We never cut less than .375" thicknesses, though- and most
things were cut from several bars or tubes laid next to one another
and tack welded at the far end, making a 2-3 blade effective for
almost everything.

I still have a thick fat nail on my left big toe
to remember one of those weights by, as a 3 or 4 year old, going in our
shop, against the rule, but there were always people and things going
on, so a real magnet for a little guy, however one time when I passed
by the power hacksaw just when a not properly clamped weight fell down
it landed on my toe, and got as a result a fat nail on that toe, got a
licking too for being in the shop when I wasn't supposed to be, I
learned some things the hard way.

I've learned a lot of things the hard way, but luckily, no major foot
injuries. These days, I wear steel toes at all times, even when not
in the shop- though unfortunately, I've never had them save my toes.
Everything that ever fell on my feet has landed right on the top,
where the protection isn't!