I’ve had too many near misses to even give that a try. (one is too many, but it seems to take two or three times for my fingers to listen to my brain) I try to remember to remove power tool leads from the power outlet when adjusting things like router depths, or changing grinder blades.
Why would you not just turn off the router for a second or two?
Please…
Re. Completely opened bottom
I’ve seriously contemplated it and last night I decided that’s the way to go — but only after looking at my already printed prototype with the bottom opened up more, yet not all the way. And mine has pretty much a full lid on top — for ze floating Zed! 
PS: this is for a “bristle” approach with floating Z — and my plan is to use craft foam for the bristles.
This image shows the groove where either bristles or craft foam [or TPU printed bristles] would be inserted:
You can print it thinner or thicker as needed.
The volume of that corner should be considerably larger than the hose diameter. It then immediately gets restricted by the table on a close cut. I made it that way to get the suction nearer to the dirt, but I very well could be wrong. I did not do all the flow calcs just made sure the volume never gets restricted. The dust skirt I did make was the outer parameter like you have shown. I figured that would catch any stray projectiles and concentrate the suction down.
Think of it more in three dimensions, that is why the little V is in there. Instead of just a circle near the bit.
It is like the game of operation! I used to have a larger opening to do that, now I just hit pause and turn off the router. if I forget to put it on.
Good oh! I think there’s an argument for redirecting the flow a little - perhaps with a bigger fillet on the “opposite” side, but you’ve still got quite a lot of restriction I think.
Watching and wishing I was far enough down the track to take make some comparative measurements.
I will probably try to test effectiveness of partial versus full open!
Glad to hear am not the only one that forgets to add the lower dust shoe. Will try pausing. Up until now the risk, reward and consequences have felt more like…
I like it. This thread might turn into us actually getting a rad dust shoe 8 1/2 years later!
I guessed there was a reason - and despite what might be inferred above, I didn’t for a minute think that you hadn’t considered all of the above. I have spent way too much time trying to get the dust extraction stuff to work nicely to extract fine dust particles so know how larger volume lower velocity works a bit intuitively, but the higher velocity of the vac is new territory.
I suspect that the restricted flow actually increases velocity in this situation, which I think is a good thing for chips and saw “dust”, but perhaps not so much for the finer particles.
One day, I’ll get to measuring that.
And as usual, I’ll arrive after the party! 
No worries, I did not take it that way. Truth is I guessed. I made a choice with the room I had and printed a few of them and cut them in different ways by hand. I never saw a difference. Other that a bit of painters tape. This is just one of those things that works well enough for me not to spend any time on it. I only try occasionally when I get an idea because I know people want a skirt.
I will try and keep up with this as well so i can integrate these into the dust shoe i am working on.
I don’t know. It’s overture TPU, never figured that out. 
The bristles have just been added.
I should not allow myself to be distracted like this, but I’ve had this door draft excluder which I bought for this exercise on the LR2, and we all know how well that went!
EDIT - yes I know the printed part is upside-down, sorry for any confusion - it was just to illustrate the concept.
The cool thing about this stuff is that the metal is very malleable and can be carefully bent at an angle to give a flared brush - my mad thought, based on the dust shoe at the head of this thread, was to create a “bottom” shoe that was concertinaed on the outside of the (modified) stock one. In TPU which at full compression would be maybe half the original depth and would simply drop down to double? I have no idea if it would work, the angled brush is an attempt to make stiffer bristles slightly more pliant,
This is as far as I’m going for now - I have a space to tidy up so I can get back into building a machine!
If anyone wants to try here is where I stopped. mount-Fusion and TPU skirt-Fusion
From what I remember the skirt need to be a bit thicker for the TPU I had and the magnets need to be larger, and/or add a third magnet.
Nice to see you also went the magnet route. I am now talking myself into you having copied it from me. 
Shoot, it could be. I started that one October last year so if that is when you posted yours that is it.
I originally left the two little extra ears on the vac part because I was not sure how well the snap function would work, and magnets were the fall back. It did work and I never went back to remove it. Adding magnets to my BOM would increase the pricer per machine probably $3-4.
Nope, mine was from January. You win. I really like the approach you went there, having the bristles further out would allow you to make them longer without them being sucked into the router.
Never know I didn’t actually get it working until Feb when I posted it on Instagram so maybe yours pushed me over the edge to finish it. I do look at the forums everyday.
I used the wire to my z axis 0 gage by acident for that worked vwr well just hard on the probe attached
