Dust shoe ideas for Burley MPCNC - Ideas and progress thread

@Snakerake

If you want to share your ideas and any sketches on this, please do so.

I’m probably going to do some work with this setup as-is and then see how it works. I may be worrying over nothing,.

Rob

Take a look at this video: https://www.youtube.com/watch?v=SIc24IAu3zE at around 9:35. His build here is nothing special, but I thought the concept was interesting (especially the double hinge), and it stuck with me. I built my enclosure with more clearance over the machine than he has, so attaching the hose centered over the spoil board works fine, and I ended up not needing his mechanism.

@robertbu

Thanks. I’ve just had a look and understand it now. I hadn’t seen that video as I had lost the will to live waaaay before then. I’m not a big YouTube fan TBH.

I’ve just done two plaques for the local park, simple enough signs saying “No Dogs”, I had to do a lot of surfacing as the wood was very uneven. A perfect test for my new dust show and the dust extraction system.

Sadly, it was a complete failure, the dust buckets I used were recycled feed containers that I got from a farmer. They were a perfect size for me and air tight. I attached a Dust Commander to the top and even braced the lid with wood. It appears that even a slight vacuum pressure was too much for the plastic and it buckled and allowed air in. Thats my hypothesis as virtually nothing came through even with a low pressure. I may have to bite the bullet and buy ‘proper’ buckets but:

  1. I think they are expensive for what they are. A 25L bucket with lid is around £11 no matter where I look.

  2. There are so many I have no idea which might (or might not) work. What we have available in the UK is not what you have in the US, so I can’t even pilfer those ideas.

I would buy one of these

but they are too tall. I have 750mm under my workbench and so have to fit a Dust Commander (300mm) plus right angled adaptor (60mm) plus dust bucket in that space. That means the bucket is a max of circa 400mm and these are 500mm. :frowning_face:

If anybody can recommend a UK supplier of a bucket and lid that works, please let me know.

Thanks

Rob

To fit below my CNC, I went with a Dustopper and a 5 gal bucket ($3.50 USD). I don’t know if they have Dustoppers in the UK, and you likely don’t want to purchase one since you already have a Dust Commander. There are also DIY dust collections solutions built from a bucket and some PVC pipe that are shorter than the Dust Commander and a bucket. In tests the DIY solutions performed nearly as well as commercial solutions if the bucket is kept reasonably empty.

https://www.amazon.com/Dustopper-High-Efficiency-Dust-Separator/dp/B0799QBX26

@robertbu

I did look at those but the only ones that seem to be around in the UK are the Triton ones and they simply weren’t in stock anywhere here. I did look at printing out the bits and converting a bucket but I just decided to but a Dust Commander and have done with it.

I thought the rectangular plastic farm feed buckets would work as I could stack one inside the other for strength. Well that was a mistake :slight_smile:

I did look at printing a bucket and therefore have the strength, but I simply can’t get the volume I need, e.g. max radius is 10cm, height is 20cm so 10^2 x 3.14 x 20 = 6.2L, a little small. I also needed to make the lid air tight and just thought it too much effort.

I have now ordered three 15L buckets so will stack one inside the other and cut the hole for the lids. I hope they will be strong enough.

The buckets are here Weds, so will have a hack at the lid, sorry, will carefully cut out a 61mm hole, and see if they work. I can then remove the 1cm of sawdust from my CNC machine after doing some surfacing work.

Rob

Here’s the conduit arm I mentioned. Pretty simple and easy. Sorry for the poor lighting.

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@Snakerake

We’re both doing something similar. I have my super structure AND a pole on top of that, It wasn’t being shown in my pictures as I was experimenting with positioning at the time.

Does your rod rotate at all or is it fixed? Also the pole seems to do power but not dust, is that correct? I can see what looks like a large dust extractor at the back of the pictures or it might be a large rocket launcher :slight_smile:

Rob

I’ve been thinking about the double (or triple hinge) idea and can see some flaws in it (or I think I can).

I have a section of vacuum hose in front of me and was trying to think through what a hinged system would look like.

I hold one end of the hose tight in my left hand in a vertical axis and hold the hose in my right hand at 90 degrees to the hose, e.g. horizontal. There’s a nice gentle bend in the hose.

If I move the left hand in a Y movement, i.e. perpendicular to the way the hose is hanging, there is a significant twisting motion as the hose rotates. The left hand holds the hose tight, simulating a tight fit on the Z axis, and there is a turning motion in the right hand. I think that the angle of movement in the right hand is directly proportional to the length the the left hand moves at right angles to the hose. Moving the hose in line with the hose doesn’t produce a turning effect.

The amount of torque produced is significant and is due to the hose being inflexible in a motion at 90 degrees to itself.

I don’t know if this is significant but it is certainly enough to turn my hand and the larger the Y axis movement, the larger the turn. Something somewhere has to give.

I can’t work out how other hose systems avoid this if (and only if) they clamp the hose tigjhjt on the Z axis. Any hose would have this turning effect, perhaps people just ignore it?

Rob

I have resolved the issue by making a prototype cheap and cheerful adaptor that joins two hose’s together.

One side of the adaptor can rotate reasonably easily (it’s plastic on plastic with PTFE tape in the middle) so it’s a cheap bearing. The other side is locked down and uses a 32mm clamp.

This allows the hose that is connected to the dust shoe to travel on the Y axis and rotate easily (circa 130 degrees) but stops the torque effect on the rest of the hose at the adaptor.

An added advantage seems to be that I can use less hose between the top of the CNC machine and the dust shoe reducing weight more. Before I was using more hose to allow for the torque effect.

The (ahem) PTFE bearing is just to test the idea out and check it works. If I hold each end and move the hose in X, Y and Z I can see the hose rotates in the adaptor but that’s not transferred to the rest of the hose.

I have a cheap roller bearing on order ($5) and I’ll modify the adaptor to use that. Will then try the double hinge out.

Rob

The rod rotates freely so the router can tug it easily. It’s loose inside the straps and rest on the woodblock. Its just carryies power now - but I’ve got some lightweight dust hose to install eventually.

Yep, that’s my dust collector piping in the background - it goes over to my table saw with an accessory hose for my palm sander. I’m hoping it will pull enough to work with the mpcnc - but I’m still working on dual endstops - dust collection next.

@Snakerake

Thanks for the explanation. I’d love a table saw (checks number of fingers and limbs), but space is at a premium, the garage has to store seven mountain bikes, shelving for all the stuff one accumulates, one GasGas trials bike, CNC machine, telescopes, jet wash, car roof box etc etc etc. Sigh.

I need space and lots of it and thats the one thing we lack in the UK, land and space are expensive.

Oh well, nowt I can do about it, so lets press on.

I have designed a hose adaptor that takes a cheap roller bearing. The hose is split , the end to the dust extractor is clamped to the adaptor, the hose to the dust shoe fits into the roller bearing and it allows the hose to rotate easily and so removes the torque on the Z Axis. The first prorotype worked well, but there was still friction and some torque feedback, so for the cost of a $5 bearing, I made a second prototype

The green item is a shim as the hoses and the bearings aren’t the same size and a bearing that fitted was really expensive.

I think this and a hinged support arm to support the weight will significantly reduce the load on the Z axis.

Rob

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First tests with the new dust shoe were mixed, it was either mostly a disaster or completely a disaster depending on your point of view.

  1. The intake on the dust shoe got clogged very quickly. I suspect the internal supports were to blame here.
  2. Waste material got blown out of the top of the dust shoe.
  3. Waste material got blown out of any gaps on the bottom of the shoe.

However the rotating host support worked well so I’m looking on the bright side :slight_smile: The only reason the supports were in the dust shoe was because I wanted to be able to print without using slicer generated supports which were a nightmare to get out afterwards.

I’ve redesigned the dust shoe adaptor that fits onto the main Z axis to just be a plate.

I will have two (very powerful) magnets on the top of the above plate which will connect the bottom half of the adaptor to it using two separate mounting supports.

image

This now gives me a little more flexibility and provides a clean path through the dust shoe to the hoses without any obstructions. I can experiment with different depths to see what works best.

I also have redesigned the actual dust shoe that fits under the router to remove all the air gaps as best I can.

I need to work out a simple flap that fits on top of this to block the U shaped channel. I need the channel so I can slide through the router bit after setting the Z probe. Small magnets may get used :slight_smile: Conflicting demands.

Oh well, it’s all learning… Lets see how this goes.

Rob

Will you be fitting brushes around the bottom? Another set of the same brushes could cover the u-shaped channel.

I had brushes around the last one. I didn’t appreciate the amount of air and dust.

There will be brushes around the bottom and now around the top and anywhere else that might exhaust waste or air.

Am finishing printing off version 41 overnight and will try again weds evening.

One step forward, one step backwards.

Rob

Get in a step sidewards, and you’ve got yourself a nice little boxstep going!

@kvcummins

Sometimes it feels like it.

I’m mocking up various things at the moment to try and see what works. At the end of the day, I can try and think through every problem or I can try something and iterate around until I get an acceptable solution. The magnets are a nice way to try different ideas out without gluing everything together.

I was amazed at how strong magnets are now. These are 16mm (5/8"?) diameter and 3mm (1/8") and will pull over 2Kg (4+lb). I struggle to pull them off each other.

Anyway, printing some stuff overnight. Lets see what problems tomorrow brings.

Rob

Something I learned when working with magnets in my dust collector. Don’t heat them up. I heated some up to fit into the pla better. They apparently lose their magnetization? It kind of makes sense, but I didn’t realize.

Yea, heat will kill a magnet.

I thought it Would work kind of like sinking a nut in a nut trap. I heated them up with a soldering iron and pushed them in. But they didn’t work after that.

I use Gorilla glue to fix the magnets in as it was to hand.

However I’m rapidly going off Gorilla glue as it expands so much and have starting looking at other options such as the Cyanocryolate glues. Epoxy resin is great for big pieces of work, but for a few mm’s it’s simply too much hassle.

Rob