Router table heat build up.

[Rich Engelhardt]

If I enclose my router with a plastic door with vent slots, how big of a concern is heat build up?

My present setup has all the dust collection done from right behind the bit on the fence.
Where the router sits underneath, it's open on the front and back.
I was thinking of adding a back and a door with vent slots and moving the dust collection to down below the table.

Should I be concerned about heat?

I'm using a Milwaukee 5625-20 in the table.

[Greg Quenneville]

Rich, I enclosed my router compartment and ran my dust collection to the back of that compartment. Then, after dust caused a failure in the router I went to both the fence and the cabinet and its been good since. Regarding heat, I would be very surprised if you have vents that you would have a heat issue.

[Jim Becker]

Unless you are running for hours on end (which isn't a good idea for a router anyway), I doubt you'll have an issue. But you can further reduce the risk by collecting from the enclosure as well as from the fence. A 4" port on the box with the combination of some ventilation holes down low to "sweep" debris from the box as well as the opening in the table and a connection to the fence will provide good air flow to cool the motor.

[Frank Pratt]

I have DC run to the fence & motor enclosure with no heat or dust accumulation.

[Jack Frederick]

I built my own box and collect from below and the fence. It is leaky air wise but does not pool dust in the box and the old PC stays pretty clean as well.

[Jim Dwight]

I used a router table set up on the side table of my table saw for awhile. I put a box around the router, a PC690. I had a 4 inch dust collection point on the bottom of the box. I noticed the router was getting what I think was too hot. I thought about it and the DC was pulling air in the opposite direction the router was trying to pull it. That does not seem good to me. So when I built my current dedicated router table, I put the collection point for the in cabinet hose up in the collet area. That way the DC helps the router fan move air through the router. I think it works better this way. I also have a 2.5 inch collection point on the router table fence (the hose in the cabinet is 4 inch).

[Dave Sabo]

Should I be concerned about heat?

ABSOLUTELY.

The router's motor (and electronic if present) is cooled by air passing over it. If you restrict/choke off the air available to cool it , what do you think is going to be the result ?

[Lee Schierer]

My router cabinet has a 1-1/2" x 20" slot cross the top of the door that is open. Running the 2Hp Freud router for as little at ten minutes without the cabinet dust collector running the air in the cabinet gets very warm inside.

[Rich Engelhardt]

The router's motor (and electronic if present) is cooled by air passing over it. If you restrict/choke off the air available to cool it , what do you think is going to be the result ?I'd be concerned it would cause it to run too hot - which is why I'm asking about it & trying to gather information based on others' experience.
From the responses so far, it looks like I should add a dust collection port to the underneath and make sure the door has some way of letting air through - slots or holes.

[Jim Dwight]

Remember that the cooling air for the router motor flows from the end opposite the collet to the collet area. You do not want to reduce that airflow. Air collection on the router table fence tends to increase the cooling flow. Collection from below can reduce the cooling flow unless it also is applied at the collet area (not the other end of the router). It was not hard for me to arrange it that way because my router table has a home made lift with a carriage around the router motor that closes off the interior compartment. I just had to put a 4 inch flex hose so it ends at the same level as the collet. On a simpler cabinet, I think I would just hard pipe up to the collet end or run flex up there.

[Dave Sabo]

I'd be concerned it would cause it to run too hot - which is why I'm asking about it & trying to gather information based on others' experience.
From the responses so far, it looks like I should add a dust collection port to the underneath and make sure the door has some way of letting air through - slots or holes.


Correct.

The difficult part is how much air to let in, and where. Like Jim mentions , you could be shooting yourself in the foot by placing it in the wrong spot. Trial & error / experimenting with your setup will be necessary to find the balance

[Jack Frederick]

The picture of my box doesn’t show another 1.5” hole I drilled for the power cord. The next time I do a run, I think I will flip the plexiglas to see if there is a difference in DC. That would introduce the air to the collet area. This is the SS router table and I also pull of the SS fence. My question is, how would you know the system is/isn’t cooling adequately. Seems it is kinda “hit and hope”, like my golf game. If you are carrying sufficient air to clear the debris that would seem to indicate adequate air flow. As routers were not really designed for table use you just have to make sure you aren’t over burdening the equipment and looking for build up. Correct?

[Rich Engelhardt]

If you are carrying sufficient air to clear the debris that would seem to indicate adequate air flow. As routers were not really designed for table use you just have to make sure you aren’t over burdening the equipment and looking for build up. Correct?More or less correct.
My table at present is open underneath. I have a box with a hose connection right behind the bit & it does pretty good at catching a lot of the chips/dust. I was thinking of adding a back & a door in order to reduce the amount of stuff it puts out as much as I can.

I don't push the router by running it for more than a half hour at a time - if even that.


My question is, how would you know the system is/isn’t cooling adequately.Good question. I can only think of one way - touch it and see how hot it is. Not real scientific, but, unless there's a better way that's all I got!
I guess I could always put my basic electronics training to some use and build a digital thermometer to monitor the temperature. I might do that one of these days.

[Jeff Roltgen]

how would you know the system is/isn’t cooling adequately.

From experience, I can tell you, you'll first notice it on the mounting plate if it's metal. Gate to bottom enclosure inadvertently got closed on my table one day. Almost done routing - maybe 20minutes, and man, I could not hold my hand on the top. This is on a cast-iron table with aluminum lift insert, large porter-cable motor. Totally shocking how much heat can build in a box like that in short order.
Vents not enough- they were still open. Active flow through from dust collection source is a must.

[glenn bradley]

I'd be concerned it would cause it to run too hot - which is why I'm asking about it & trying to gather information based on others' experience.
From the responses so far, it looks like I should add a dust collection port to the underneath and make sure the door has some way of letting air through - slots or holes.

I have a 4" duct at the rear of the compartment and a door with holes in the front. Between the vents and the throat opening of the router (which varies with your insert) you want about the surface area of your exit port. In my case is about 12 sq in.

[johnny means]

If your router is overheating, it's not because of airflow. You'd have to be trying to create that condition to make it happen.

[Dave Sabo]

If your router is overheating, it's not because of airflow. You'd have to be trying to create that condition to make it happen.


This is simply misguided advice and would be TOTALLY INCORRECT with my setups.

Put a router in a enclosed (mostly) box not much bigger than the router and run it for a few minutes. Then measure the air temp and report back to us. If the air used to cool the motor is not replaced it will become quite warm.

We can debate whether or not heat is an issue for router motors in another thread.

[johnny means]

This is simply misguided advice and would be TOTALLY INCORRECT with my setups.

Put a router in a enclosed (mostly) box not much bigger than the router and run it for a few minutes. Then measure the air temp and report back to us. If the air used to cool the motor is not replaced it will become quite warm.

We can debate whether or not heat is an issue for router motors in another thread.

Like this table? Getting warm is not overheating. It doesn't take that much air exchange to keep a healthy router within operating temperatures. You'd need to hit oven like temperatures within the enclosure before the circulating air ceased to have a cooling affect. A router should comfortably operate in the 200c range. I can't imagine a whole lot of conditions where the average user would insulate one well enough and run that long to exceed that.

[Edwin Santos]

This is simply misguided advice and would be TOTALLY INCORRECT with my setups.

Put a router in a enclosed (mostly) box not much bigger than the router and run it for a few minutes. Then measure the air temp and report back to us. If the air used to cool the motor is not replaced it will become quite warm.

We can debate whether or not heat is an issue for router motors in another thread.

Well as embarrassed as I should be to admit it, I committed this very sin. My router table had an enclosure for the router with an access door with no vents in it.
Things were fine until I got the bright idea to add dust collection to the back of the enclosure to supplement the existing dust collection at the fence on top.
Well my router bearings burned up a short time later.
What happened was the dust collection was creating a vacuum inside the router enclosure which in turn starved the router of airflow. Drilling a few holes in the access door to approximate the size of the dust port created enough make-up air to resolve the problem and the router with replaced bearings has been running fine ever since.

[Dave Sabo]

Like this table? Getting warm is not overheating. It doesn't take that much air exchange to keep a healthy router within operating temperatures. You'd need to hit oven like temperatures within the enclosure before the circulating air ceased to have a cooling affect. A router should comfortably operate in the 200c range. I can't imagine a whole lot of conditions where the average user would insulate one well enough and run that long to exceed that.

Johnny , what I’m saying is you can only speak for your setup.

Advising guys not to worry because your specific setup hasn’t cause you trouble is not sound advice. Especially when you don’t know what router they’re using or what their table setup or dust collection airflow is.

In the very next post after yours , Edwin had exactly the issue I said is possible to create if one is not mindful of all piece of the equation. It happens more than you’re aware.

p.s. which router makers claim their products will run in a sustained 200c environment ? That’s almost 400 degrees Fahrenheit !

[Roger Davis]

There is a product called the Milescraft 1501 Dust Router that uses a silicone cup that attaches to the bottom of the router table plate insert to capture dust at the router bit and attaches to a shop vacuum. This along with the Incra Clean Sweep magnetic metal insert rings will capture ninety percent of the dust. Since the airflow to the vacuum works in conjunction with the router’s internal motor fan that passes air through the motor to the router bit thus preventing sawdust being pulled through the router motor as would happen if the router is enclosed in a box.