My advice (free and worth every cent) is to take a step back and go with a shop vac for router dust collection. DC's (like those you mentioned) produce a lot of air flow (cfm), but at a relatively low vacuum (static pressure). They're particularly good when you need to move a lot of air for picking up a lot of material and/or large dust particles, such as when using a planer or jointer. Tools such as that usually have dust collection ports 4" or more.
The problem with routers, ROS, and other handheld tools is that the dust port is much smaller- 1-1/2" or less, in my experience. While the big DC's can move a lot of air, they just can't suck enough through that small opening, because they don't have a high vacuum.
OTOH, a shop vac has higher vacuum, so it can suck dust through that small port better (but isn't nearly as good for the big tools).
My personal rule of thumb is: If the tool dust port is < 2" (e.g. handheld tools), use a shop vac for DC. If the port is 4" (or more), go with a DC.
I have a couple of stationary tools (Ryobi BT3100 table saw and Ridgid band saw) which have 2-1/4" (shop vac hose size) ports. I go with whichever hose is more convenient at the moment. For those, I'm not sure I can tell any difference between my DC and shop vac for dust removal performance.
That said, in deciding on a shop vac, I'd look at how much vacuum it can produce, and how noisy it is. Personally, the high pitch whine of a shop vac is really irritating, to the point that I built an insulated box to hold my vac, and for long sessions use ear muffs.
Finally, the best dust collection equipment you can get is a good respirator mask, esp. when routing and sanding. Your lungs will thank you.
Just my .02 Good luck and keep cutting!
I +1 to John, I'm connecting a shop vac to the router's fence and it works very nicely, almost no dust exposed. The only problem I noticed is when you have to make a groove with a considerable distance from the fence, so the dust goes.. everywhere, since the hose is connected to the fence. In this case, I think a hose that is under the router bit would work.
Even though I'm still unsure of how the dust ports will add up on the router table if I use both fence and router dust adapter (and/or router-box), I went ahead and got a shop vac.
From some reviews, the Ridgid WD1450 appeared to be the quietest/least-annoying of the high-powered shop vacuums.
I've only switched it on briefly, and it sounds more like old canister vacuums I remember from childhood. Indeed much less annoying, and even somewhat quieter, than my small old weak Ridgid vac.
Financially, it's also more pleasant than a DC: The green HF 1 hp DC would have been the same price after 20% coupon, but to use it without outside venting (not realistic for the foreseeable future, and I have Christmas presents to work on - we're down to 19'F tonight) would cost close to $200 in filtering.
Even if whatever dust separator I'm going to build means I never have to change the filter, that's a lot to spend right now compared to the Ridgid HEPA filter and drywall bag for less than $50.
...and some of that money may be best spent on a Bosch VAC05 hose, perhaps.
Hoses is where I'm a little unclear, and it's holding me back a little on the separator construction:
Freehand routing, most of the time - the dust adapter on the router gets the entire air flow, any hose between 1.25" (router) and separator pipe dia. will do.
Table routing: If I use the router dust adapter on the router, that's a 1.25" dia hose size. I assume that whenever that's hooked up, I don't really need any vacuum on the router box. But how much flow do I divert to the fence? (And at what point would this combo do better with a big DC?) Is a 2 x 2 x 1.25 Tee or Y sufficient, or do I need to restrict the fence flow more to maximize router adapter flow?
Similarly, I've been using a grid-shelf as a makeshift worktable with a cardboard box underneath to catch dust, and it's struck me that a more solid version of this, with suction on a sealed box underneath a porous (so to speak) table might be a good idea for freehand routing even with the dust collection on the router itself going.
Again, how would one split off the flow for this sort of thing?
Or am I overthinking this? Will the fence or table router dust adapter each work so well that only one is needed at a time (i.e. use blast gates)? Or do you just hook them together however the hoses fit?
Or do you give the router adapter more flow, such that the fence gets more just whenever the bit hole is mostly covered by the workpiece?
Or do you just change blast gate openings whenever it doesn't quite seem to catch enough?
On the separator side, do I spend extra money and wait time to get flanges like this
Air Tools Accessories - Woodstock 2-1/2 Universal Dust Port W1042
online and then fight with actually getting my hoses (not to mention a PVC elbow) to fit these,
or do I go the cheap all-PVC route which moves the fight to getting the PVC pipes to seal against the lid?
