Router Table + Dust Collection Location

[Ray Newman]

Colleagues: am seriously contemplating shop fabricating a new router table. But have question about dust collection location.

1) Been told that routers draw cooling air from the router top, exhaust it from the bottom/bit end. Seen router table designs with the dust collection port at the bottom of the router enclosure with an open space/holes in the enclosure access door to draw in air. This is how my current router table is set up and it leaves some dust and chips in the enclosure.
Question: does this starve the motor for cooling air?

2) Also seen router tables with the dust collection port and opening to draw in air placed under the table at router plate level. Supposedly, this design is much more effective to remove dust and chips. Question: does this starve the motor cooling air?

3) Would it be better to have the dust collection mounted under the table at router plate level and open space/access holes on the bottom of router enclosure access door? Dust collection would draw in cool air from the bottom with the air pulled by the dust collection system and router fan into the router and exhaust it at the bit where the warm air and dust/chips would be pulled into the dust collection system?

Or am I just over thinking this??

[David Linnabary]

All of my airflow goes back through the base of the cabinet then out to the collector. As it worked out, the hose connections were more simple and less cumbersome running back into the base. I have 3 points of collection; underneath, behind the fence/cutter and lastly, in front of the fence/over the cutter. I can run all 3 at the same time if I choose. It all runs back through the cabinet base so the router has sufficient air flow to cool.



David

[Jim Becker]

If you have your router surrounded by a cabinet, you need to put some air inlet slots or holes near the bottom across from the DC connection to provide a "sweep" of air to mostly eliminate any material hiding in the cabinet. The total air inlet area from both the fence and the cabinet should be close to the area of the DC inlet. It's a math problem, in other words.

I have these slots at the bottom of the access door to the cabinet and there is little or no material left behind.

[Vince Shriver]

I saw a router table plan that had a tube (for lack of a better word) secured around the top of the router (picture a piece of duct material) that went from the router thru the bottom of the dust box under the table. Dust was then evacuated thru another port in the dust box. The router was always running on fresh clean air when in use. I thought it was clever; if I see it again I'll post it.

[glenn bradley]

Could be a bit of overthought here. "Trick" setups can overcome inadequate air flow for the job to some extent. Acceptance that the motor chamber doesn't have to be as pristine as an operating room will also help. The airflow will create "snowdrifts" of sawdust in the nooks and crannies of your chamber. Once filled the path is pretty self sustaining.

I pull via a 4" chamber port at the bottom rear connected to a 2HP cyclone. The return air inlet is in the door as you describe but, is at the top causing the flow to pass by the plate throat opening and motor. I started with a dummy door, drilled a row of holes that was just shy of the area of the exit port and added area until I got an optimal flow. I then made the keeper door with openings of this area.

[John Lankers]

There are a few things to keep in mind for router table dust collection:
1. You don't want the dust laden air get drawn through the router motor!!!
2. You don't want a vacuum inside the motor box when the workpiece covers the opening in the tabletop!!!
IMO, the best place for the dust port (preferably 4") is in the back of the cabinet right below the tabletop with an adjustable fresh air intake (round 4" adjustable air vent) on the opposite side but lower than the dust port so that fresh air gets drawn up, somewhat diagonally through the motor for cooling, then the dust laden air drops into the stream above the motor and gets carried out.
This and a 2" port on the fence takes care of all the dust with very few exceptions.

[Robert Engel]

I think John ^ is correct. Building your dc into the fence will get at least 80% of the dust. I think a shop vac with a cyclone is ideal for this.

I think dc inside the cab is pretty much a waste of time. The dust that goes below into the cabinet is easily vaccuumed out periodically. My cabinet has a simple drawer in the bottom that I dump periodically.

I disagree about dust in the motor. I've never found it to be an issue but once in a while I blow out the motor with air.

[Glenn de Souza]

You're not overthinking it. I built a router table cabinet originally with dust collection at the fence only and an access door to get to the router. The access door basically created a closed chamber that became a vacuum due to the router's fan trying to draw air out of this chamber. As a result I burned out the bearings on one router prematurely by not realizing what was going on.

I now have dust collection at both the fence and a port going into the chamber to collect from in their also. To alleviate the vacuum by providing make-up air, I drilled a series of holes in the access door so now there is an air current which draws downward falling dust but also feeds the router motor with air. There is a balancing act between providing too much make-up air and too little. If you provide too much, the efficiency of the dust collection can drop and if you provide too little, you can starve the router like I did. Someone mentioned matching the sq in. area of the dust collection duct. I think I ended up close to this guideline but maybe a little less so I probably have a very slight vacuum but not nearly enough to starve the router.

Personally, I think you need dust collection both above and below the table. Think about routing a groove where the bit is buried in the work. Above table dust collection will do nothing in this circumstance. This said, if I was forced to choose one or the other, I would go with dust collection at the fence.