Here's what I did, if I can describe it well enough:

Using a standard male-to-male shop vac hose adapter, it fits pretty tightly over the largest round outside connection on the ROS - right where the dust bag fits over. Then the hose hooks directly to that.

I found that the vac likes a little more air than it gets with the pad flat on a surface, so I drilled four 1/2" holes around this adapter, so it can draw a little ambient air in. This works exceptionally well, as it catches most of the dust coming out from under the pad.

But then the adapter cracked, it's a little too tight on the sander, so I put a hose clamp on it. Now what I have is an adapter that clamps tightly to the ROS, and draws enough ambient air to both keep the vac motor cool and catch what little dust the thru-sander holes miss. As an added benefit, it doesnt come off no matter what, as it's clamped tight. Works like a champ - I dont use any face mask, even when sanding epoxy. I do use earphones though. Wrapping the sander cord around the hose keeps it all together.

That cheezy oval thing doesnt work worth a hoot.

: Please let me know what I am missing. I bought a new Dewalt ROS (DW 422) at
: Home Depot. The display and box said it comes with an attachment for a
: vacuum. I have a Rigid Vac, and for the life of me I can't figure out how
: to make them mate.

: The instructions don't mention any adapter or anything.

: The sander works great, very quiet, and removes material fast, but I'd like
: to use it with the vac. Any suggestions.

: Thanks in advance.