In article ,
Winston wrote:

Here, a few months ago, I wondered aloud what would
happen if I clamped my saber saw underneath a work
surface so that I could free up my hands to guide
the workpiece. This would allow me, for example to
do miter and notch cuts in steel quickly and accurately.

I tried it and found that I couldn't hold the workpiece
down against the face of the surface for some reason.
I jumped to the conclusion that I needed a larger
'orbital' blade clearance setting but even with that
set for maximum 'return clearance' the work still
vibrated uncontrollably. I wondered what could be the
cause but vectored off to do other chores instead of
engaging in any analysis.

This morning, a commercial on teevee revealed the cause.
Our friends at Rockwell discovered that the
blade was flopping laterally and have included an upper
guide to minimize that. Apparently it works
well enough, if very slowly, even in wood.

https://www.rockwelltools.com/US/Bla..._source=BRTV&u
tm_medium=TV

After watching the demos, I'm convinced that this approach
won't work for me because of the swarf that will jam
in the upper blade guide, causing damage to it in short
order.

Still it is cool to see how they addressed the 'floppy
blade' issue.

Now, I wonder how to make a large jigsaw that uses regular
hack saw blades to do many of the things that the Blade-
Runner is shown doing, without tearing up a blade guide
in the process.

I looked at the product reviews at Amazon.com. These saws are very
light (17#), and just are not made that well, so it's hard to assess the
idea.

Joe Gwinn