No that design was not a really good one, I just liked how the TPU bristles worked out.
That is the biggest issue with any bristles, the stiffer they are, the more they will actually mess up your cut and push your Z axis around. It is a fine line with too soft, and too hard. This idea of mounting the shoe separate from the router is very appealing just for this reason. It will let us use stiffer bristles.
I’m using fabrics tape as a skirt and it’s working quite well.
looking forward to that outcome!
fwiw, I use plastic that one tends to lay inside a kitchen drawer to protect the inside. it is both flexible & stiff enough. Obviously took the idea from @Tokoloshe
His shoe worked fine for me (although I must admit it broke down yesterday 
)
Very cool! I now printed a skirt/bristles in TPU that works a lot better. 
Uploaded it to printables (Printables).
Thanks @vicious1 and @Dreyfus for those ideas, i like the fabric idea.
and thanks @Tokoloshe for that link, I actually printed your magnet version of the dust shoe, but didnt notice the TPU dust skirt. Can you remember what “hardness” of TPU you used?
As Ryan said its a fine line between too hard and too soft.
Has anyone considered a completely open lower part? It may well have happened during the design phase, but presently that right angled bend restricts airflow considerably. (I’d keep the router vent baffle in place for now - but I also wonder if with no baffle and an open path to the vac and a decent skirt it might assist? It might also create a lot more airborne fine dust.)
Perhaps it accelerates it and enhances the vac effect, I don’t know.
What I do know is that the diameter of the inlet is 45mm, this reduces to 45 x15 which is about 40% of the area of the vac hose.
I’ll have a 51mm hose so it’s about a third.
If it hasn’t been done - I will muck around with that.
Next year!
Lower dust shoe that can be safely added/removed during a job would be nice.
Has anyone else tried adding or removing the lower shoe, while the router is spinning, only to realize that isn’t going to work without unpleasant consequences?
Well,
Funny you said that, like i said i used your design and i had to drill some holes in the bottom of that right angle bit. I am sure that has not helped my problems as the skirt now gets sucked up into them.
So I am defiantly interested in the answers to this, for the other design i am playing with.
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.
