On 15 Jul 2004 15:19:48 -0700, (Joe Emenaker) wrote:

"Puff Griffis" wrote:
On the show " Ultimate Workshop" on the DIY network they said that the
flex hose slows down the air current thus robbing power from your DC.

Yeah. I'm expecting a Delta 1.5hp DC for my birthday next month, and
so I'm doing a lot of reading on how to "duct-up" the shop. Almost all
of the articles seem to be in agreement on the following principles:

o 4" is good. 5" is gooder. 6" is gooderer.

Maybe. It really depends upon distance and the size of your dust
collector. 6" may be *too* good and reduce velocity to the point where
chips settle out. You really need to do the velocity/static pressure
computations to be sure. In my case, 6" was too large, 5" was the ideal
size. Unfortunately, that meant I could not use cheap PVC from the Borg.

o Try to avoid any hose/tubing that's not smooth inside.
o Try to avoid tight turns (ie, use 45-degree bends instead of
90-degree).

Yep

o For the same reason to avoid tight turns, avoid right-angle "T"
joints and opt for the "fork-in-the-road" style "Y"s.


Again, yep

I'm taking so much of this as religion that my current dillema is
this. I'm also planning on building the home-made cyclone in
ShopNotes, but its outlet is at the top and the DC that it feeds into
is going to have its inlet either waist-high or at the floor. So, I'm
debating either raising the DC onto a platform or modifying the
cyclone design so that I can get a more-or-less straight shot across
from the cyclone exhaust to the DC intake.

- Joe

Check out the various web sites like
http://cnets.net/~eclectic/woodworking/cyclone/
it has an Excel spreadsheet:
http://billpentz.com/woodworking/cyclone/StaticCalc.xls that is invaluable
in sizing your system. Pay attention as well to sizing the ductwork for
each machine.

I just went through this late last year and have been very satisfied with
the results. I wound up buying metal spiral pipe from a local fabricator
along with Y's, T's and elbows. I can now see plumes of dust being sucked
into the table saw through the insert and the shaper table chips are sucked
into the system with few residuals left behind.