Larry Jaques wrote:
On Thu, 29 Sep 2011 06:43:59 -0700,
wrote:

(...)

I tried it and found that I couldn't hold the workpiece
down against the face of the surface for some reason.

You need a workpiece holddown. Howzbout a rubber inline skate wheel
on a stick, held from above, parallel with the blade direction?

Nuh uh. Read on. De blade be floppy and binds in de cut.

(...)

Prolly holddown. The machine tends to vibrate and it's passed off into
the workpiece, plus the effects of the blade cutting.

Floppy blade. The workpiece resisted all attempts to
seat on the table, despite a considerable amount of
clamping pressure provided by yours truly.

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/BladeRunner_Saw-P1564.aspx?utm_source=BRTV&utm_medium=TV

Oh, GAWD, I'm glad I dumped my DISH contract! I watched one of the
little videos they had and instantly remembered.

"It came back to me like the hot kiss on the end of a wet fist."
Thank you Firesign Theatre

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.

Will a dust/swarf-collecting vac help?

Some. Not enough, though.
One chip trapped between the blade and the bearing
and it is 'bye bye guide', I conjecture.

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

With a holddown/guide, eh?

Yup. The guide bearings damp the wobbly oscillation
of the end of the blade. The foot shown would have
been quite inadequate to resist the 'workpiece hop'
I saw, sans blade guides.

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.

Use a wire instead of a guide. Tension the upper end like a coping
saw or scrollsaw.

Food for thought.

--Winston-- Loves his bandsaw but it won't cut steel and
decent blades are spendy!

Buy a new tool!
http://www.harborfreight.com/portabl...saw-47840.html
$99, on sale for $79, less a 20% coupon you might have = $64 plus $20
for a trio of bimetal blades.

Neat looking saw. Not 'general purpose' enough without
a table, though.

--Winston

--
I see the Kitchen in splotchy black granite
based on a "Pink Floyd meets the 50's and 60's" theme.

Think 'Shoo-Wap Doo-Dah Ummagumma UbaTuba'.