Dust shoe, to move or not to move...

Hi

When it comes to dust shoes there seem to be two major designs:

• Fixed Z, that stays at a constant Z throughout the cut.
  Like Suckit https://www.suckitdustboot.com/ or similar
• Variable Z that move with the router as you cut.
  Like the design @Chris Laidlaw (Magnetic Dust Collector for Blue OX Router/Spindle Mounting Kits | eBay)
  
• (Then there is the articulated version by fellow Swede @Eric Jacobsson The Floating Dust Shoe)

Which flavor do you prefer?

It seems to me like fixed Z would be more predictable. I.e. it would be easier to determine if it will hit anything throughout the cut. It also seems more complex to design...

 

The floating dust shoe is very nice.

Here is the dust shoe I used to have (before Z-axis upgrade). The design is three parts. The nozzle-mount, the brush and the hose holder.

The nozzle-mount

It attached to the side of the Z-axis C-beam with two slot-in T-nuts. It's possible to adjust the height of it by loosening the T-nuts. I routed them out of MDF on the CNC two parts and joined them using dowels. The nozzle is attached using friction fit.

The brush
The brush part is made up of a 2mm (or so) sheet of lexan on the top that is attached to a frame by using screws and captive nuts. These screws are also used to snap the brush to the nozzle mount with some magnets that are embedded in the nozzle mount. On the outside of the brush frame I attached two layers of a thin foam sheet using hot glue. The two layers were cut in an overlapping fashion. This way, there shouldn't be any direct path for a chip to escape through the the "brushes"

The hose holder
The hose holder attaches to the top of the Z-beam while still allowing the the Z-axis pulley to move freely. I also added some extra holes to allow access to the M5s at the top of Z. The hose simply snaps in to the "pinch".

Comments
I think the designed worked pretty well overall. When cutting aluminum, I think just having the brushes there to physically block the chips made the biggest difference. Overall, it prevents the dust/chips from spreading too far but it isn't 100% effective at extracting them.

Pros

• Side design makes it fairly compact
  
• The overlapping foam-pad "brushes" seemed very effective.

Cons

• Side design eats a bit of work area.
• Wasted airflow from the non-working side of the shoe.

A picture is worth a thousand words so check out the images. Unfortunately, I couldn't find any images with it still mounted to the machine so a few renderings will have to do.

I hope someone finds this rambling useful.

 

Looks like a good, straigthforward design. Do you find that it works well even without a brush that acts as a physical barrier? Also with that small inlet hole?

I've considered trying to duct something from the back but never found a solution I liked. It always seem to eat too much Z travel.

 

Some renderings of the new design. I bought myself a 3D printer that I'm planning to put to good use.

The design is inspired by suckit. The two channels on the sides will allow for adjusting the height of the shoe. It's a fairly complex design (by my standards at least). Hopefully I'll actually print the thing one of these days.

On design decision I made was to have a fairly large hole on the router side of things. I'm thinking that the airflow generated by the router could aid a bit in chip clearing. Hopefully, the shopvac should be able to overpower it and prevent the dust from escaping the boot. Compared to my old design I've also added a curved part that redirects the airflow and prevents it from simply sucking air in through the brushes that are closest to the hose.