building a dust shoe

[cyclestart]

Question: The router has a built-in fan to blow dust away from the work. Should the top plate of the shoe have a hole as large as the router diameter, allowing the router to blow into the shoe ? OR should this air be exhausted outside the shoe ?

Question 2: If the inlet to the vacuum is small (2" ?, thinking about a dust deputy), is there any good reason to use a larger hose or inlet at the shoe end ?

[ger21]

1) I know a lot will disagree, but I prefer the air blowing down on the part. A properly designed shoe should keep all the dust in, and the air will help to ceap the chips out of the cut. In fact, my next router will have additional compressed air blowing on the cut to clear the chips.

2) No, it will decrease performance. Imo, though, a 4" dust collector will work a lot better, and is a lot quieter.

[johnmac]

The suction CFM needs to exceed the CFM of the router motor cooling fan. Otherwise, saw dust will be left behind.

It would be nice to see a good side by side comparison of the two designs, with pros and cons of each type.

John

[zeeway]

My dust shoe clamps around the router...does reasonable well, but still doesn't blow all the chips out of narrow cut paths. The outlet of the shoe should match the diameter of the hose of your dust collector - putting a larger outlet will only slow down the velocity of the outlet air. A dust collector with a four inch hose will certainly work better than a dust deputy and a two inch hose.

[cyclestart]

Hmmm, 2 thumbs down on the small diameter and I know you guys are talking from experience. Dust deputy has a larger cyclone for more $ and it's a fair guess (?) that the cost of the rest of the system goes up in proportion. This may come down to a pocket book compromise unless someone has a suggestion for flowing large air for relatively small money.

[ger21]

Find a coupon for a 2HP Harbor Freight Dust Collector for $139. They're in several woodworking magazines, and I've heard they're good until September or October.
I got one about 6 months ago. I use an older 1HP dust collector with my router, and the HF with my other tools. The Harbor freight has tremendous suction, and is far and away the best bang for the buck you'll find.

Check Wood Magazine, American Woodworker and This Old House magazine.

[zeeway]

I also use a Harbor Freight 2 HP dust collector. It uses 4 inch pipe and it really sucks (in a good way).

[PropNut]

I have to vote for the 4" hose also. I tried the 2" route and found that there was not enough suction to pull up everything..the result was crud bouncing around the cutter while it tried to work.

A couple of pictures of my DiY setup:





Not an original design, I saw it on Youtube and made my own.

[johnmac]

Not an original design, I saw it on Youtube and made my own.[/QUOTE]

But you did answer a couple of questions. Sucking up the router motor exhaust with the dust can be done, but it does need the CFM volume of a 4" collector.

John

[PropNut]

I should clearify something, the 4" hose is connected to a 3ph Jet dual bag 1900CFM vacuum system. I doubt that a router can move as much air as even a good shop vacuum. I believe that the benifit of the larger hose is to deliver the full measure of CFM all at once to lift larger pieces out of the way immediatly (this,unfortunatly includes parts that you do not intend to have removed...really gotta make my tabs larger, lol).

[CarbonKevin]

My first dust shoe was a 2" diameter vacuum brush sealed to the underside of the router/router mount, with a 1-1/4" fitting for the vacuum hose. Much of the air blowing through the router actually went up the pipe, and the air draw from the vacuum probably improved the airflow through the router body. Trouble is, very little air flowed up through the brush, so performance sucked. Also, it wasn't possible to change bits without first removing the dust shoe.

I'm now using a more traditional skirted shoe with 2-1/2" hose. I've found that this works a bit better, since the skirting does help contain dust, but at the same time, the downwash from the router does seem to be hindering performance.

Seems if the air being drawn through the router could be dissipated away from the cutting area, the chip pickup would be free to work far more effectively.

Also - for same airflow rates, isn't a smaller hose going to generate faster flow velocity? Going to a 4" hose gives you tons of flow, but if the air is moving slowly, isn't that counterintuitive since it'll stop you from being able to suck up heavier/larger debris?

[ger21]

Originally Posted by CarbonKevin Also - for same airflow rates, isn't a smaller hose going to generate faster flow velocity? Going to a 4" hose gives you tons of flow, but if the air is moving slowly, isn't that counterintuitive since it'll stop you from being able to suck up heavier/larger debris?

No. But, you can't use a 4" hose with a shop vac, and you cant use a 2-1/2" hose on a dust collector. With a router, it's unlikely that you'll get any heavy or large debris. There's a lot of info here on velocity and CFM.
http://billpentz.com/woodworking/cyc...cs.cfm#Airflow

Imo, the most important thing is to have a good seal with the brush. You'll never get 100% of the dust, but a good seal will get you nearly 100% of the airborne dust, and that's really all that matters. The little bit left on the table is quickly cleaned up with a shopvac. The main goal is keeping the rest of the shop clean, and that's easy to achieve.

If you do want 100% dust collection, and have a 10HP or bigger spindle, you can try one of these.

http://www.dustfreenesting.com/