In this video I am going to make a dust shoefor the CNC machine.
I’m going to base mine on a two part designwhich uses magnets to attach the brush section to an upper part which is clamped onto thespindle.
You can see this Parametric Dust Shoe by CNCRouterParts.
Comand a similar one by KentCNC – which I’m using as inspiration.
Theirs sells for quite a lot but the materialcost shouldn't be too high.
The main different I will make, is splittingthe bottom section with the brush into two so I can more easily remove them to changebits.
I am cutting out a practice piece from 9mmMDF to check the design before I use more expensive acrylic for the final version.
I made this design from scratch, using anolder version of ArtCAM.
However, this version isn’t available anymore and their subscription software is really expensive, but you could create a vector filein software like Inkscape, for free.
So this this came out really well.
I am really impressed.
The finish is not too bad considering I useda 1/8 of an inch bit which was probably about 30mm long.
So that's quite a long bit.
If I used a smaller bit that's held up inthe collet a bit higher I probably reduced some of these lines at the bottom, which tobe honest are barely visible.
That's a really good finish.
And the thing I suspect and will double checkthis now.
Look at that, barely went through to the wasteboard.
This measured as 9.
12mm and I set that inthe software, and it didn't cut into the waste-board at all.
It's so accurate.
I can't believe I've built a machine withbirch-ply plates and it cuts better than the bloody xcarve.
It is difficult to clamp stuff down on sucha small bed, I feel like I'm really wasting material because I'm trying to hold everythingflat.
That really should have been all the way overthere but I was nervous about putting a metal mending bracket so close to edge.
Of course if I clamp something like this Iwouldn't have any room.
Because of the fixed deign of top section,I will have to make different bottom section with various length of brushes to cover thedifferent bit and material depth combinations.
So I've bought a couple strips of this brusheddraft excluder.
Each one cost about 2 quid from my local Wilko.
And I've done the sensible thing of actuallycutting my template and test dust shoe out before I had the chance to measure the metalalong here.
It's a little bit bent because I've alreadytried to bed it.
This all comes out.
It's a pretty decent price for two quid, andI've obviously spent four for this.
What I'm going to try do is check whetherI can cut it, how it's assembled, whether the brushes fall out, if I can bend it andso no.
I did look for flexible brushed draft excluderbut couldn’t find anything here in the UK.
The rigid stuff in contrast was really cheap.
By the looks of it I think the way this ismade, there is a wire that goes in the centre of the brush which is laied out like that,and it is folded over with this piece of aluminium to keep it in position.
And that sorta crimps over the central rodor whatever's in there.
In retrospect it would have been easier ifI had design the grooves for the brushes as a collection of straight lines – but thatmight have impacted the feng shui of the machine.
Alternatively I could have used Ethylene-VinylAcetate or EVA craft foam sheets.
You can get these in various thicknesses andthey can be glued and are easily cut.
I decided to make a template to clamp thebrush-strip against, and create the shape I needed.
The machine might seem a bit slow, but that’sbecause the acceleration is still left at 10mm/sec2 – but as I’m still getting toknow how this machine operates I’ll play around with that when I feel a bit more confident.
The channel is a little tight for the brush,so I will adjust the vector file to compensate.
I am now drilling some holes into the acrylicto work out the offset needed to get as tight a fit as possible for the magnets I will beusing.
Ok I've just spent an hour trying to cut differentholes out doing area clears just to see if I get the setting right.
The feed-rate and step-over so this 7mm magnetcan actually fit inside and I've managed to get it to the point where I've had to hammerit in, and I can't get it out now.
But that's not a bad thing because I essentiallywant this to be stuck in there, and if I can avoid using any glue that's even better.
It took a while to get the setting right butin the end I used an RPM of 15000, a feed rate of 620 mm/min and a plunge rate of 200mm/min,and the thing no one ever tells you – a step over of 25% of the bit width.
I am using 1/8 of an inch bits which is 3.
175mm,so 25% of that is roughly 0.
79mm.
Knowing the step-over is important becauseI’ll be doing an area clear for the magnets and the brushes.
The bits are quite long, and this can effectthe speed and step-over.
Shorter bits are more rigid and thereforeyou can go faster, a longer bits can more easily flex and should be ran slower.
The chips look amazing on this.
I mean nothing melted.
It looks like snow.
So I made a few mistakes in the end, crackingthe acrylic where I would pass the clamping bolt through and realising I wanted to changethe design after I had cut parts out.
Ahh you f**k.
The size of the machine screw heads was alsotoo large and left a gap between the top and bottom pieces of acrylic.
I'm not sure how that will effect the extractionif I'll be pulling air from here as well as from the bottom.
I eventually cut a few different versionsas I went along, and even improved my drilling technique.
This is how drilled the hole for the clampingscrew, learning from the mistakes from the first attempt.
I used a centre drill bit to first mark whereI would drill through and also placed a piece of mdf between the gap to prevent the piecesflexing.
I added small 1/8 inch through holes wherethe magnets would fit so I could push the magnets out if I ever needed too.
and Idid.
I also noticed that magnets become weakerif they are struck – so here's some advice, don't use a hammer.
I eventually changed to machine screws withsmaller diameter heads because one magnet was moved out of alignment when acrylic wasclamped to the spindle.
But these were also thinner could use that1/8 inch through holes to push the magnets back so they made a positive contact.
andI simply push.
The last thing I did was use larger garagedoor draft brushing, to make a second dust shoe attachment.
I had to cut each section in half so it couldshape and push them into position.
This was arduous work and my hands were achingafterwards.
That was hard.
So you probably want to see this in action,and here it is.
I'm cutting a piece of MDF.
I’m actually cutting a test plate for thesecond version of this CNC machine.
I designed this on Fusion 360 with parametersto help develop the design and solve some of the problems with the first version.
The joke it I have redesign the CNC machineto the point now that if I make a new one, I will also have to redesign the dust shoe.
So this is not the ultimate dust shoe.
Anyway if you want to see see the walk-throughvideo where I explain what I have done on Fusion360 I’ll link to that at the end ofthis video.
Thanks again for watching.
Source: Youtube
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