Dust collection- Saw cabinet very "airy"

Both my table saw cabinet and jointer "cabinet" have lots of gaps allowing air flow from dust collector. Is this by design? For instance, the saw's motor-access door has a 6" X 10" square hole in the top where it mates with the cabinet when the access door is closed. Wouldn't this decrease the efficiency of the dust collector (1.5 hp Delta dust collector). The Delta jointer is even worse. Should I try to close up these holes?
--
KB
Saint Charles County, MO




Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If you were to seal all the holes so no air gets in, the DC won't work. The dust collector does not suck dust, it sucks air and carries the dust with it. Perhaps someone will post the perfect method for your tools, but if not, experiment a bit. Leave enough air gaps to at least equal the exit port. The opening would ideally be opposite the cutting blade so the air passes the chips as they are made and carries them along with it.
--
Ed
http://pages.cthome.net/edhome/



Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Just having a ton of SUCTION in the tablesaw is NOT going to move any sawdust/waste. So you need air MOVING thru the saw, and especially if using zero clearane inserts you need some other way for air to get into the saw.
Bottom line, that hole is probably NOT reducing the ability of the vac to get the sawdust out of the bottom of the saw. If you want it to also get dust from around the blade, etc, then you may want to use a dust collection system attached to the bladeguard as well as dc connected to the main port of the saw
John
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You will get better dust collection closing off the holes. I made hardboard covers with foam glued on one side, a wooden handle on the other, that closes off the curved slots in my PM66. If I tilt the blade from 90 degrees, these fall on to the floor but most of time I'm sawing at 90.
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

states that "you" get better dust collection closing off the holes...
From my experience, with my Cabinet saw (using duct tape etc to experiment with) I have to agree with the others..... sealing off the gaps etc greatly reduced the effectiveness of my DC ...that is not to say that I did not seal any of the gaps..
Bob Griffiths
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I'm ashamed to admit that I once tried to sell vacuum cleaners. I failed miserably at it, but one thing I did learn was that even with the greatest vacuum power, it's still necessary to have adequate air flow for it to work properly. The difficult part is to find the optimum level between too little and too much air flow.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Bob G. wrote:

I agree with Bob, in that one cannot completely close off all the holes, and the more holes that are closed off, the faster the airflow will be where it counts: at the blade (You'll always have a hole there).
Now, doing this MAY create a small pile inside the cabinet because the amount of air that is moving, but at that point, who cares? The goal is to reduce airborn dust particles.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have a Delta contractors saw and a Harbor Freight $159 dust collector. I have run with the back of the saw covered and uncovered and see no difference in dust collecting, so I leave it open. You do need some openings to keep the air moving through the saw. Greg
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
K. B. wrote:

hoods for various power tools. As I recall, the gap called for in these designs for the jointer & tablesaw is 1/2 inch. Bill's website may be reached at:
http://billpentz.com
Dave Vermilyea
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
my theoretical approach would say leave about as much area in gaps as you have in port size
e.g.
if you have a 6" port, then that is pi*r^2 or 3.14 * 3^2 = 28ish sq inches
So leave about 28 sq inches of "gaps" elsewhere.. probably near the top side of the table (around the gaps where the cast top meets the metal box) such that the airflow is down and into the port. Seems reasonable that you would want the gaps located such that the air flowing through the gaps pulls the dust towards the port.
If you leave less area than that, you are going to create a vacuum and it's not really going to help move dust. If you leave more area than that you have just going to reduce the airspeed and at some point (nothing is enclosed) there would not be enough airspeed to carry the dust.
If you have a 4" duct, that area drops to about 12 sq inches. Now you can see why Bill Penz and others insist on 6" ports!! Makes sense to me.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Thanks for all the feedback. Dave's link to http://billpentz.com was particularly interesting. The pie-r-square theory is pretty good in that it is something you can sink your teeth into- I shall try it. All the advise and comments were helpful. The experiments are on!
--
KB
Saint Charles County, MO

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I should say that much of what I know is derived from Bill's site and his email support of my DC efforts. One of the items that sticks in my mind is the fact that air is not compressible under DC conditions. Thus the pi*r*sqr theory of mine applies I believe.
wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.