I built a router table extension for my table saw. Upon using it, I
noticed that non-though dados were a problem as far as dust collection
was concerned. And I want to do a lot of non-through dados in the
middle of panels. So... I found a web site:

http://www.oak-park.com/usa12.html

where they had a vac-plate with a couple of holes in the plate for dust
extraction. I decided to drill a 1.25" hole in my top, about 10" to
the left of my bit, and put a Rockler dust port on the bottom of the
table. Now, non-through cuts toss the dust right at the hole in the
top and the dust is extracted. The problem is, when the material
covers the hole, the vac starts working pretty hard (because the port
is mostly obstructed), and begins to work as a very effective
hold-down.

Any ideas on a way to add a vac pressure release somehow? Is there
anything made for something like this that doesn't cost an arm and a
leg?

I thought of actually adding yet another hole and dust port, and some
sort of Y- or T-fitting. So when one hole is covered, the other is
open. Problem is, that would start to add quite a bit of "crap" under
the table that I don't know if I have room for.

Any ideas appreciated.

Thanks!
Phil

Thanks!
Phil

wrote:
The problem is, when the material
covers the hole, the vac starts working pretty hard (because the port
is mostly obstructed), and begins to work as a very effective
hold-down.

Any ideas on a way to add a vac pressure release somehow?

I thought of actually adding yet another hole and dust port, and some
sort of Y- or T-fitting.

I currently only have dust collection in the fence. It seems to me that
the best of both worlds would be to use a "Y" fitting and combine the
two--I can't think of a scenario where both ports would be blocked
simultaneously.

Chris

You are a wealth of information, I think I will probably implement your
suggestion. I'm still considering a down-draft enclosure as a possible
alternative. I think I can squeeze one underneath, but I have doubts
about how well it would work, and I'm not sure how I would mount it.

Thanks!
Phil

Certainly the larger the dado the less hold-down I get. I like the
idea of routing a T to the edge of the table (above). And I'm still
pondering a down-draft table.

Thanks!
Phil

On 1 Mar 2006 14:22:30 -0800, wrote:
snip
Any ideas on a way to add a vac pressure release somehow? Is there
anything made for something like this that doesn't cost an arm and a
leg?


In plumbing, there is a device called an "air admittance" valve,
designed to vent fixtures when they can't be vented to the outside.
They are designed to open when there is suction on one side, and stay
closed otherwise. Might work, but I have a feeling it may open just
under normal operation in this case. But it's only a few dollars,
might be worth a try. Search for "Oatey air admittance valve". (Oatey
is a common brand name.)

But why not make your own? All you need is a little hinged flap
closing a vacuum port with a spring holding it closed. You could
adjust the spring tension so it only opens when the other port is
blocked.... The spring would have to pull away from the vacuum and
hold the flap against a seat of some sort, but it would be easy and
quick to make something up...

Paul

Rather than a fitting to each hole, consider boxing in the router with a vac
connected to the box.
Also you may want to make the holes into a rectangles.
Mine are 1 5/8 x 1 3/16 and I have never had a problem with them blocking
up.
See pics at:

http://www.woodworking.org/photo/dis...um=20311&pos=6

http://www.woodworking.org/photo/dis...um=20311&pos=7

http://www.woodworking.org/photo/dis...um=20311&pos=8


wrote in message
oups.com...
I built a router table extension for my table saw. Upon using it, I
noticed that non-though dados were a problem as far as dust collection
was concerned. And I want to do a lot of non-through dados in the
middle of panels. So... I found a web site:

http://www.oak-park.com/usa12.html

where they had a vac-plate with a couple of holes in the plate for dust
extraction. I decided to drill a 1.25" hole in my top, about 10" to
the left of my bit, and put a Rockler dust port on the bottom of the
table. Now, non-through cuts toss the dust right at the hole in the
top and the dust is extracted. The problem is, when the material
covers the hole, the vac starts working pretty hard (because the port
is mostly obstructed), and begins to work as a very effective
hold-down.

Any ideas on a way to add a vac pressure release somehow? Is there
anything made for something like this that doesn't cost an arm and a
leg?

I thought of actually adding yet another hole and dust port, and some
sort of Y- or T-fitting. So when one hole is covered, the other is
open. Problem is, that would start to add quite a bit of "crap" under
the table that I don't know if I have room for.

Any ideas appreciated.

Thanks!
Phil

Thanks!
Phil

On 1 Mar 2006 16:29:04 -0800, "tom" wrote:

WRT your "non-through" dado, I've never heard of a "through
dado"(insert smiley-face here). One would think that there's a route
for air to flow along the newly cut dado, though. Tom

Just a WAG, but maybe it's a dado that doesn't reach the edges of the stock?

Maybe it would be a "blind dado"?? *lol*
Mac

https://home.comcast.net/~mac.davis
https://home.comcast.net/~mac.davis/wood_stuff.htm

Ridgid makes a connector/handle that has an adjustable port on it. You twist a
sleeve to progressively open the port to adjust vacuum level. It should ft any
2 1/2" hose. You can get them at Home Depot for ten bucks, here is a link to
the Ridgid web site that shows the part:

http://www.ridgidparts.com/accessories/VT2505.phtml

Dennis

I wrote:WRT your "non-through" dado, I've never heard of a "through
dado"(insert smiley-face here). One would think that there's a route
for air to flow along the newly cut dado, though. Tom


So Mac wrote:Just a WAG, but maybe it's a dado that doesn't reach the
edges of the stock?
Maybe it would be a "blind dado"?? *lol*

Ahh, or a "stopped" dado? Tom

Any ideas on a way to add a vac pressure release somehow? Is there
anything made for something like this that doesn't cost an arm and a
leg?

I thought of actually adding yet another hole and dust port, and some
sort of Y- or T-fitting. So when one hole is covered, the other is
open. Problem is, that would start to add quite a bit of "crap" under
the table that I don't know if I have room for.

Have you considered drilling another hole in the top of the table, directly
left of the router bit.
Keeping the centerlines matched up. Once the board with the dado passes
over it that should
allow air to flow thru, thus releasing the

One note though, I've noticed that when cutting dados with a 1/4 straight
bit it does
tend to leave the saw dust packed in pretty, usually need a screwdriver to
clean it out.
Maybe, consider a spiral cut bit also.

Ron