Table Saw OVERHEAD ONLY dust collection

[Rick Pinzon]

I want to know if it's practical to only collect dust from the top of the table vs from below as well. I want to eliminate running a 4 inch hose across the floor to the back of the saw. I plan to modify or buy a uard to allow for a 4 inch hose port. Do some of you successfully collect dust from the top only?

Here are the specs associated with my question: I'm a hobby DIY'er with a Dewalt job site 7491RS ble saw in a 2 car garage. I have grizzly 2 HP dust collector, super dust deputy, 2 stacked nano filters with 4 inch piping. I have other tools as well but the question focuses on just dust collection specific to the table saw. This is the setup I have now and like most everyone else its the never ending process upgrading based on acquiring money, skill, time and space.
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[Jim Becker]

You could do that, but a large volume of chips come off the blade "inside" the table saw. You'll need a solution for that as well as a plan to regularly deal with the accumulation that's not flowing to your cyclone. If you're worried about the hose on the floor when you're not using the table saw, just disconnect it when you're not cutting.

[Bill Dufour]

For most cuts there is no reason the hose can not come down from the top and branch to the base as well as the top guard.
Bill

[Frank Pratt]

By far, most of the dust is sent downward by the blade. So overhead only will let most if it get away. I have a 2" flex dropping from an overhead duct to the guard and a 6" to the cabinet. Very little dust escapes.

[Ole Anderson]

You get used to stepping over it. If you run it vertically, eventually it is going to get in the way of cutting large sheet goods unless you run it at the far right of the table extension. You really need to collect dust at the bottom. A 3" top collector seems like the sweet spot to me. SharkGuard.

[Rick Pinzon]

You get used to stepping over it. If you run it vertically, eventually it is going to get in the way of cutting large sheet goods unless you run it at the far right of the table extension. You really need to collect dust at the bottom. A 3" top collector seems like the sweet spot to me. SharkGuard.

What size is your dust collector?

[Ole Anderson]

What size is your dust collector?

2 hp Oneida SDG with a 7" main duct and a 5" to the bottom of the TS. Doing it again I would have gone with the 3 hp unit, mine works fine, I just like the better numbers on the bigger unit.

[Jim Becker]

The over blade collection for my slider uses a 3" drop; the machine a 5" drop (120mm port). My 2hp Oneida is off-white as it preceded your Gorilla by a year or three. So my setup is similar to yours, Ole. Works fine, but I need to build a new overarm type guard to use as an alternative to the riving-knife mounted guard/pickup because the OEM one is way too restrictive.

[Terry Hatfield]

Overarm style guards/collectors work well but as others have stated, they will miss a significant amount of dust that will have to be dealt with inside the cabinet. I have 4' to my home made guard and 6" to the cabinet. Works great but I do have a fairly large cyclone. Bottom line is that you really need both to work efficiently. I have separate gates for each leg so I can fine tune to whatever operation I am performing.

[Mike Cutler]

You really do need both. My overhead collector, home made, is a copy of a design by someone here on the board. It resembles the design of Terry's over blade collector.
My dust collection setup is pretty "remedial", ( Translated as cheap and poor) and needs to be upgraded. It is an older Jet DC1100, and I move the 4" flexible hoses from machine to machine as needed.
My dust collector is almost always outside the shop when in use and the hoses come through ports in the doors. I'm pretty lucky that I can keep the machine outside. If I had to have it inside, it would have been changed out long ago.
It's okay at best, but even with two pickups it doesn't get everything I really want it to. There are times, especially with the bandsaw, that it is augmented with a shop vac.

[Jack Frederick]

I wonder if the overarm dust collection performance could be improved by adding a bit of directed compressed air below the table to move the sawdust out of the blades gullets. I had a '48 Unisaw I had rebuilt and added dust collection to. I was setting up to try this when one day I came home and my daughter had gotten me a 3hp Pro SS. My thought was to let the lower primary collection do more and have to rely less on the top collection as my Unisaw didn't have any. I ended up giving that saw to a friend in need so the idea was never developed. Possible?