Thread: Router Box

Is the box for dust collection of free form routing?

If so, 1200 cfm through a cross section of 1 ft x 1ft only has an air speed of 1200 fpm or 20 ft/s (6 m/s) won't be enough to pick up the big chips and the box will fill up with these chips. To pick up chips you need about 20 m/s

The enclosed router boxes I have referred to in my posts are router table/cabinets with the router motor enclosed and vented from underneath.

Correct that is the intended purpose… how big would you define a big chip to be?
I am working on the assumption that by keeping the dust localised to the area, it has to be more efficient then letting it fly off the work bench onto the floor, and trying to pick it up from there.
Also would using it with MDF dust make any difference to the equation? As I find that most MDF dust is more like fine powder.
I was thinking of having the pickup point fairly low, as to not drag the dust up into the router, and closer to the level at which it comes off the router.
Was also thinking of introducing the fresh air from the top so as to pull the dust away from the router.

Edit:
Could through a bit of creativity make some kind of mesh floor to the box, and have a four sided sloping hood, much like a range hood but upside down so any dust that naturally get flung to a wall falls down into the catchment area.

A quick knockup of the idea...

Originally Posted by HeadScratcher

Correct that is the intended purpose… how big would you define a big chip to be?
I am working on the assumption that by keeping the dust localised to the area, it has to be more efficient then letting it fly off the work bench onto the floor, and trying to pick it up from there.

The cross over point between chip and dust is somewhat arbitrary. I equate chips with what falls out more or less immediately, smaller than that is visible dust, and then invisible dust.

Also would using it with MDF dust make any difference to the equation? As I find that most MDF dust is more like fine powder.

Yes it will but even though MDF makes more invisible dust the majority is still usually visible hence wont stay suspended in under 20 m/s. A figure I can remember is sanding MDF with 240 grit produces around 40% invisible dust.

Could through a bit of creativity make some kind of mesh floor to the box, and have a four sided sloping hood, much like a range hood but upside down so any dust that naturally get flung to a wall falls down into the catchment area.

To me it sounds like a complete enclosure would just get in the way. I like the idea of a box with mesh floor that chips can fall into. To reduce chip scatter the box could also have low sides. This is starting to sound like a downdraft table. Maybe combine that with a fume hood of some kind. That would make it easier to work under than an enclosed box as it should still grab the invisible dust. Remember that the invisible dust does not come away with anywhere near as much momentum as the chips so depending on cutter profile, the scattering of invisible and other gaseous MDF nasties from a router is probably nowhere near as bad a what the chips indicate might be the case.

A downdraft table with low sides and a fume hood above with curtains around it could be useful for all manner of power tools like planers, sanders and routers. These can be made removable to use on existing benches.

Although I want to focus on machinery for the moment, dust generation and movement by power tools is something I will definitely test in the future.

ok a low sided table could be on the cards... meanwhile I have knocked up version 2 with one side on a hinge, so it could be put down to make a smaller bow or lifted up to make a bigger box.

A door on the end for arm holes and putting materials in and out... (not shown) could be a curtain perhaps.

Not a big fan of dusk masks or crap in the face, so like the idea of the clear acrylic sheet between me and the dust.

Reverting back to a simpler idea... A dog flap on the opposite side to the working end. For as often as I would probably work on oversized wood, I could probably sweep the floor. Besides it would still limit the amount of fling off, and most would fall back into the hood below.