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<DIV><FONT style="FONT: 10pt ARIAL, SAN-SERIF; COLOR: black">The general rule is
whatever size you think you will need, buy one or two sizes
larger. Even if an adequate system works well they become less efficient
as the dust bags fill. The other critical item is the diameter of the
vacuum line. It is more important to have a large CFM volume then ultra
high VPSI. These systems work by moving mass amounts of air at once
but don't necessarily require a large amount of negative pressure to
do it. It is therefore critical that no matter how large a dust collector
you use, the feed line must be large enough not to loose CFM power in the
transfer. </FONT>If the machine has a 6" inlet you need to run 6" all the
way to the machine. Then you can reduce it to 4" at the machine
itself.</DIV>
<DIV> </DIV>
<DIV>I have a large dual chamber Powermatic system. It uses a 230 volt 5
hp motor. It has an 8" inlet but came with a 6" adapter to mount directly
on the machine which is what I used. To reduce noise and get the
collector out of my way I built a shed outside my shop and housed it in
there. I only need to flip a switch in the shop to turn it on. The
important part is that I ran 6" solid overhead spiral metal duct work from the
collector to the shop machines without reducing the size. At each machine
I installed a blast gate to shut off the flow to any machine not being
used. The machines are as follows: 5' x 6" planner, 20" throat
commercial band saw, 12" disk - 6" belt combination sander, large cabinet saw,
and a commercial 16" stationary planer. The planer is by far the biggest
hog when it comes to dust collecting. The system works well and I have had
no problems with clogs. Using 6" spiral steel duct work is <U>very</U>
expensive, particularly after adding the various "T", "Y", and "elbow" fittings,
but it makes a very professional set up with the least amount of problems once
its up and running. I might also add that I sealed the shed for
air-tightness and then included an 8" return duct back to the shop. This
prevents a negative pressure in the shop when it's running and also doesn't suck
my expensive air conditioning outside. After the cost of the machine,
building the shed, electrical, ductwork, flexible hose, and all associated
hardware, I bet I've got close to $5,000 wrapped up in the system.</DIV>
<DIV> </DIV>
<DIV>Rob Goodale, RPT</DIV>
<DIV>Las Vegas, NV</DIV></BODY></HTML>