Ooznest Workbee Z1+ quick-swappable magnetic dust shoe v0.3

Intro

This is an updated and modified version of my previous Workbee dust shoe. The previous version had a wing nut sticking out of the side (which I found a bit annoying although it wasn't hitting the Workbee frame) and the attachment to the Ooznest-supplied dust shoe holder wasn't very reliable (required shimming with electrical tape). Furthermore, if you wanted dust shoes with different bristle lengths, you'd have to reprint and assemble the entire thing, which was a lengthy and involved process compared to this version.

This version consists of four parts (Photo 1 and Photo 2).

Part 1 attaches to the Workbee router clamp and replaces the Ooznest-supplied dust shoe attachment. Even if a dust shoe will not be required for a prolonged time, it should not get in the way much and can be left in place permanently (like the Ooznest-supplied dust shoe holder).

Part 2 attaches to Part 1 to complete the upper (non-swappable) part of the dust shoe. If a dust shoe is not required, it can be removed or left in place. Note that Photo 1 has the wrong version of Part 2 showing: the square opening between the router hole and extractor hose hole is not present in this model. It is an extension I'm working on but which is not quite ready yet.

Part 3 attaches to Part 1/Part 2 via magnets and holds the actual brush strip. This is the quick-swappable part and you can have several with varying brush lengths. Two STLs are supplied, for two different types of brush strip.

Part 4 is the hose attachment. The extractor hose screws onto it and it is then pushed/twisted into the opening in Part 2.

Compatibility

This model fits the Ooznest-supplied 43 mm Mafell/AMB/Kress/Festool router clamp. I do not know whether it will fit the larger clamps. If you want to check, Part 1 has M5 bolt holes for attachment to the router clamp in a rectangular pattern, with 60 mm between left and right bolts, and 78 mm between front and back bolts.

Version

This is the all new, redesigned and (hopefully) improved version 0.3! Version 0.2 never happened. It was supposed to be a modified version of 0.1 but I gave up on it and redesigned the whole thing from scratch.

Parts/tools

You will need:

• Four M5x8 button head bolts (the ones that attached the Ooznest-supplied dust shoe holder to the router clamp are M5x6 and are too short)
• Two M3x12 button head bolts
• Two M3 hex nuts
• Super glue
• Twelve 10x5x2 mm neodymium magnets. I got mine here. An extra six are required for every extra brush strip holder (Part 3)
• 50 mm diameter polyurethane flexible ducting hose. I got mine here. This is less rigid, easier to route, and puts less weight/tension on the dust shoe than the 38 mm (ID) black PVC hose used in version 0.1, but is more expensive. A coupler is provided if you want to join the PU hose from the dust shoe to a longer run of the cheaper PVC hose.
• Brush strip, approx. 60 cm per brush holder. Initially, I went with a stitched base brush strip from Amazon (Photo 3) as this was cheaper than the rubber base strip used in version 0.1 (Photo 4). However, I found that the stitched base strip had rather dense and rigid (thick) bristles which could cause the Z axis to struggle and even skip steps if it tried to lower the router vertically onto the brushes without a ramp move, or even detach the brush holder if the bristles hit the stock horizontally high enough up the bristles. The more expensive rubber base strip is better in that respect in that the bristles are softer, less dense, and bend more easily. I recommend the more expensive rubber base strip over the stitched base strip. Part 3 is provided with spacing for both (5.5 mm for the stitched base, and 8.3 mm for the rubber base).
• Not strictly necessary, but a heavy duty paper guillotine comes in very handy when trimming the brush strips to the required bristle length and you want a straight cut (do this before inserting the brush strip into the brush holder). The bristles (especially the thick ones on the stitched base strip) are surprisingly tough to cut! Also handy for cutting off the thin part of the rubber profile (Photo 4) if you went with the rubber base brush strip.
• Needle nose pliers (and an extra M3 nut) may be helpful for inserting magnets (Photo 5).

Assembly

Print all four parts in PETG and 0.2 mm layer height. I used 30% infill and 3 bottom and top layers and perimeters. Part 1 requires supports (on build plate only), the other parts don't. Make sure you print the correct Part 3 for the brush strip you intend to use.

Insert four magnets into the magnet holders in Part 1 and push them all the way in (Photo 6). You may have to clear any artefacts or blobs from the magnet pockets first. If they're still difficult to insert, you can use an M3 nut and needle nose pliers as in Photo 5. Magnet orientation does not matter yet. Attach Part 1 to the router clamp with four M5x8 bolts from below (Photo 7).

Insert two magnets into the magnet holders in Part 2 and push them all the way in as before (Photo 8). Magnet orientation does not matter yet. Part 2 attaches to Part 1 using the two M3x12 bolts and M3 hex nuts (Photo 9). The two parts have intermeshing tabs. Some force may be required to fit them together but they should fit eventually (some tolerance is designed into the model). In the worst case you could file off the tab surfaces somewhat where they collide with each other or the router clamp. The bolts go in from above and the nuts from below. Note that Part 1 has hexagonal nut traps on the bottom side into which the nuts should fit.

Insert six magnets into the magnet holders in Part 3 and push them all the way in as before (Photo 10). This is where magnet orientation becomes important. Make sure that they are oriented so as to be attracted to the corresponding magnets in Part 1/Part 2. Take a magnet, let it attach itself to one of the magnets in Part 1/Part 2 from below, then transfer the magnet in that orientation to the corresponding holder in Part 3 (the little square windows through which you can see the magnet surface need to point upward, towards Part 1/Part 2). Repeat for the other magnets. Note that the magnet holders have pin holes opposite the magnet insertion slot through which the magnets can be pushed out if required.

Now insert the brush strip. Whenever you're cutting the brush strip to length, make sure you seal the end with super glue to prevent bristles falling out from the side. Also make sure you have printed the correct Part 3 for the brush strip you intend to use (stitched base strip from Amazon in Photo 3 or rubber base strip from ZeroPlus in Photo 4). If you're using the rubber base strip, you will need to cut off the thin part of the rubber profile (see Photo 4): a paper guillotine comes in handy here. The rubber strip I still had left from version 0.1 of the dust shoe has this “h” profile (version 0.1 requires it) and needs cutting but the website also sells a brush strip with square profile (they call it “c” profile) where cutting is not necessary. Just check that its thickness is the same as that of the thick part of the “h” profile (approx. 8 mm), they have a datasheet somewhere on the website.

Start by inserting the brush strip from the square corner into the long side of Part 3 as shown in Photo 11. Go around the circumference and out again at the square corner. It should be pretty obvious. Trim the excess brush strip. This can be flush to Part 3 for both types of brush strip, or leaving 1-2 cm excess for the stitched base strip, and then bending the protruding part toward the side of Part 3 and fixing with super glue (Photo 12, a spring clamp may be useful here until the glue sets). Don't forget to seal the cut end of the brush strip with super glue to prevent bristles falling out.

Part 4 screws into the polyurethane tubing (Photo 13) and is then pushed/twisted into Part 2. Attach Part 3 with the brush to the bottom of Part 1/Part 2 and you're done (Photo 14)!

Important

Note that the magnet holders on Part 3 (the swappable brush holder) have shallow square registration holes on top, and the Part 1/Part 2 magnet holders have corresponding protrusions on the bottom: these fit into each other when correctly aligned and prevent the brush holder from being pushed off the router assembly when the bristles are pushed sideways against a workpiece (within limits). The registration holes/protrusions are fairly shallow but they have to be in order to keep the magnets close together. Taller protrusions would provide more immunity against Part 3 being detached if the bristles hit an obstacle but the magnets would be spaced further apart and you would lose magnetic adhesion. This is therefore a trade-off and a shortcoming that I'm aware of. I've only done a few test cuts so far and these were quite shallow so I kept the ends of the bristles slightly above the stock at Z=0 and they were only in minimal contact with the stock at full cut depth. Yes, chips did escape from the initial gap but remember that this is a “dust shoe”, not a “chip shoe”. If this turns out to be a problem for deeper cuts, I'll revisit the model. As mentioned before, I'd recommend the more expensive rubber base brush strip because its bristles are softer and more flexible so less possibility of Part 3 being knocked off. Please let me know if you run into any issues with this!

I have printed several of Part 3 and fitted brush strips with varying bristle lengths (Photo 15). A paper guillotine comes in handy when trimming the bristle length: the bristles in the stitched base strip are remarkably tough!

The black PVC hose from version 0.1 is too stiff and heavy and applies too much weight and tension to the dust shoe. The (more expensive) polyurethane hose is therefore used in this model. But the black PVC hose can be used further down the setup on the way to your extractor. If you want to join these two hoses, a coupler is provided (Photo 16 and Photo 17). This has an outer thread for the PU hose, and an inner thread for the black PVC hose. It should be pretty obvious. To minimise vacuum loss at the connection points (and also in Part 4), the joints can be sealed tightly with Parafilm or cling film.