Ventilating a router table cabinet?

[Kevin Kelly]

I want to build a cabinet for a router table, which will serve as the fence table on my table saw. The router's a pc7518, if that matters. I'll put in a dc port, but do i need to provide any ventilation holes around the motor?

[Rod Sheridan]

Hi Kevin, if you are extracting dust under the table you will need to provide make up air.

An opening area (or sum of all opening areas) of 50% larger than your exhaust hose area will be fine.

If you are exhausting a significant amount of air out of the cabinet, the router motor will be properly cooled.

Regards, Rod.

[Rick Moyer]

Hi Kevin, if you are extracting dust under the table you will need to provide make up air.

An opening area (or sum of all opening areas) of 50% larger than your exhaust hose area will be fine.

If you are exhausting a significant amount of air out of the cabinet, the router motor will be properly cooled.

Regards, Rod.

Are you saying that for a 4" DC hose A=3.14 (2"x2")=12.56", one would need 18.84 sq.in. total openings? seems like alot. Or did you mean 50% OF the exhaust opening 6.28 sq.in.? Just curious.

[Rod Sheridan]

Are you saying that for a 4" DC hose A=3.14 (2"x2")=12.56", one would need 18.84 sq.in. total openings? seems like alot. Or did you mean 50% OF the exhaust opening 6.28 sq.in.? Just curious.

Yes, that's correct.

Inlets cause a lot of restriction, adding 50% to return air intakes is a good average.

Regards, Rod.

[Larry Rasmussen]

I can't provide a formula but certainly the amount of suction is a variable to be considered. Funny I put the vent in after reading a discussion here about how you needed one if the suction was too high and caused extra noise at the intake or whistling, venting the router motor wasn't mentioned. My router dust collection box extends down to the mobile base so has more internal volume than many do.

My dust collector is an older Jet labeled as 1 HP and 650 Cubic Feet/Minute. The table end has a 4" collector out the back of the box and a separate 2 1/2" hose running out the back of the box and to the top collector on the router fence above and behind the bit. This combo of input and output works just right for suction without noise at intake areas or stress on the collector.

Here's the part that may be worth reading. Given the post I read about the need to vent just as I was building the table I put in a 4" blast gate on the box right in front of the router. The set up works fine without opening it for extra ventilation. I am doing this again because I also open the blast gate to adjust the speed setting on the router- really quick and easy but a little tight on the access. I'm in the process of boxing in the motor on a table saw wing mounted router. I think I've seen 5 or 6 inch gates at Peachtree and will be ordering one of those as vent/access door this time around. If you did this with either the 4 or 6 inch blast gate you'd be covered if you needed to vent.

Luck,
Larry R,
Seattle

[Lee Schierer]

I agree with Rod. You need to have at least 25-50% more inlet opening as you have exhaust opening so as to not restrict the air flow. You can't suck much air from a closed box.

I once ran my 2 Hp Freud router in my router table for about 5 minutes without the DC running. I was amazed at how hot the air in the cabinet got in that short run time. I always turn on the DC now.