# The 'Blokebox' drop-box



## woodbloke (24 Jan 2010)

Here's my finished drop-box, apart from the input and output ports that have yet to be cut (awaiting 'ose :wink: ) 
The interior is as on Mike G's thread: 







except that the main vertical baffle has now been moved to within about 75mm of the input port 






The front has been fixed using 10 toggle clips made from some 6mm ply and screwed under a little pressure (applied with cramps) to get the seal. A window has been cut and fixed with some hot glue on the internal rebate. 

A close up of the toggle fixing is shown: 






All internals have been sealed with copious quantities of silicone so it ought to be pretty airtight - Rob


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## MikeG. (24 Jan 2010)

Power it up Rob, and report!

Mike


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## woodbloke (24 Jan 2010)

Mike Garnham":1rfbp9z5 said:


> Power it up Rob, and report!
> 
> Mike


No 0's  yet. I'm hoping that this is going to work (I can't see any reason why it ought not to [-o<) and if it does, then I plan to build a ginormous one for the 'shop extraction system later on, with the sucker as the Camvac 386 - Rob


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## TrimTheKing (25 Jan 2010)

I'm still not sure I understand these. I am not doubting they do their job, and I _will_ be making one myself, but can either of you explain to me whether you lose any suction from the original source?

I read in one of the posts that the baffles disturb the airflow, slowing it down so that the dust drops in the box (which makes sense and I am fine with), but do you ultimately lose any 'suck' from your extractor?

Looking good btw Rob, interested to see it in action...


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## wizer (25 Jan 2010)

The thing I can't get my head around is the loss of space. With one of these, you double the footprint of your extractor. Ok, I understand if you build a small vac above the drop box. But on chip collectors or something like my RSDE2, you double the footprint by using one of these. :-k dunno, maybe I'm looking at it through wizer tinted glasses....


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## mickthetree (25 Jan 2010)

I find it hard to get my head round as well Mark, but my basic understanding of it is that it shouldn't matter the size of the box (in theory??) as long as there are no leaks, you are still moving the same amount of air through it.

Is this right??

I'm guessing that for a very large box there might be a lag when it starts up as it creates the initial vacuum within the box?? But I'm just guessing.


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## TrimTheKing (25 Jan 2010)

mickthetree":3t4voqk3 said:


> I find it hard to get my head round as well Mark, but my basic understanding of it is that it shouldn't matter the size of the box (in theory??) as long as there are no leaks, you are still moving the same amount of air through it.
> 
> Is this right??
> 
> I'm guessing that for a very large box there might be a lag when it starts up as it creates the initial vacuum within the box?? But I'm just guessing.


That's kind of how I understand it too mick, but it's the 'slowing down the air' part that I don't get.

If you slow down the air inside the box, but are still sucking it out at the rate the extractor can manage, then surely you run out of air to suck at some point...

Please excuse my dumbassery, I am learning sketchup at the moment so anything else I know has fallen out of my brain :shock:


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## MikeG. (25 Jan 2010)

TrimTheKing":21lhktgk said:


> but can either of you explain to me whether you lose any suction from the original source?



No Mark, I couldn't detect any drop in suction. I did a simple test.......holding the biggest sheet of ply that the vacuum could suck up without the box, then seeing if it managed the same with the box attached. Not a perfect test.....but no discernible drop.

Mike


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## woodbloke (25 Jan 2010)

TrimTheKing":1rpjn2od said:


> I'm still not sure I understand these. I am not doubting they do their job, and I _will_ be making one myself, but can either of you explain to me whether you lose any suction from the original source?
> 
> I read in one of the posts that the baffles disturb the airflow, slowing it down so that the dust drops in the box (which makes sense and I am fine with), but do you ultimately lose any 'suck' from your extractor?
> 
> Looking good btw Rob, interested to see it in action...


Mark - I'm puzzled with that one as well, but I'm trying very hard _not_ to understand the physics of the thing as it'll give me prolonged brain ache. I'm going with Mike's guidance on this as the dropbox guru and future world grand supremo (and abolitionist of decent hand planes :lol: ) that the thing _will_ work - Rob


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## MikeG. (25 Jan 2010)

woodbloke":3g7yclk0 said:


> (and abolitionist of decent hand planes Rob



No, I shan't abolish them Rob, I'll just set a limit per person.  

Mike


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## BMac (25 Jan 2010)

This 'slowing down air' business got me too until I compared it to sediment tanks in a sewage treatment plant. The water rushes in and out but the body of water hardly moves at all to allow particles to drop. Maybe the air acts the same way - rushes into the box, slows when the volume increases and then gets sucked out at the same speed at the other end?

Brendan


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## TrimTheKing (25 Jan 2010)

BMac":oalnf7t4 said:


> This 'slowing down air' business got me too until I compared it to sediment tanks in a sewage treatment plant. The water rushes in and out but the body of water hardly moves at all to allow particles to drop. Maybe the air acts the same way - rushes into the box, slows when the volume increases and then gets sucked out at the same speed at the other end?
> 
> Brendan


Makes sense, cheers Brendan.


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## Mr Ed (25 Jan 2010)

Mike Garnham":20z7vpnq said:


> woodbloke":20z7vpnq said:
> 
> 
> > (and abolitionist of decent hand planes Rob
> ...



So long as that limits about 10 I'm with you comrade. Come the revolution...

Ed


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## woodbloke (25 Jan 2010)

BMac":27mc4c6i said:


> This 'slowing down air' business got me too until I compared it to sediment tanks in a sewage treatment plant. The water rushes in and out but the body of water hardly moves at all to allow particles to drop. Maybe the air acts the same way - rushes into the box, slows when the volume increases and then gets sucked out at the same speed at the other end?
> 
> Brendan


That makes sense...easier to visualize :shock: So if the input port and output port are approx the same size, there ought not to be too much of a difference in the amount of air passing through the box...it just gets slowed down in the middle to drop the sawdust or chippings - Rob


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## DavidE (25 Jan 2010)

TrimTheKing":2zu4p9f5 said:


> BMac":2zu4p9f5 said:
> 
> 
> > This 'slowing down air' business got me too until I compared it to sediment tanks in a sewage treatment plant. The water rushes in and out but the body of water hardly moves at all to allow particles to drop. Maybe the air acts the same way - rushes into the box, slows when the volume increases and then gets sucked out at the same speed at the other end?
> ...



Good example Brendan - a similar way of thinking about it is rivers.. where the river is wide you get a slow flow etc and also on the corners the rocks and stuff build up on the inside (think of a car differential).

There will be some loss - as one of the laws of Thermodynamics tells us "You can't get something for nothing". However, if you try to maintain the minimum area available the same as the input/output pipe it should be minimised. You'll get losses in energy from the flow travelling over a longer path, from making it change direction and from throttling it (what the baffles do). The magic is getting the scale right so that when you cause the dust to drop out the affect on the flow is minimal.

This is why I mentioned in the other thread using a Cyclone off a vacuum cleaner with a larger extractor may be problematic is it will create quite a constriction and thus will be lossy.

Hope this helps
Cheers
David

PS Rob - good looking box you need to get those holes sorted and it working!


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## Ironballs (25 Jan 2010)

Laminar flow is what you're talking about in sewage plants, you're trying to achieve the same effect here but in a much smaller space, hence the baffles.

As long as you have no holes/leaks then the old rule of every action has an equal and opposite reaction should apply, in other words, what goes in must come out


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## woodbloke (30 Jan 2010)

The 63mm tubing was ordered from Axminster last night so should be here on Monday. With any luck and a following wind I ought to have it up and running on Monday evening - Rob


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## Qwibble (30 Jan 2010)

Davids advice sounds good. Keeping the scale appropriate, minimising use of baffles and sharp changes in direction. These cause turbulence and result in air friction. The extractor will have to work hard against this friction and this will reduce the amount of air it can pull though the box. 
Mike seems to have got it pretty much spot on with his box, with minimal losses and good dust droppage.

Once I get my workshop up and running (working on moving house first!) I'll have a go at making a dust collector. Design wise I'm thinking of a round dustbin with a traffic cone on top (think Wizer and his dunces hat).
Dusty air inlet will be in the middle of the bin, facing downwards. The large increase in volume should cause the velocity (and the dust) to drop dramatically. Air will be extracted from top of the cone. The gradual increase in velocity up to the clean air outlet might just result in lovely laminar flow and minimal loss of sucking power. Fine dust will still get through, but that'll be fed to Henry.

I could be very wrong about all of this. But once I sart building it I'll sort out a WIP and keep you posted. Qwibble BEng (Hons)

EDIT: And nice looking box Rob, it'll be interesting to see how it performs. I'll stake a pound that it'll eat all visible dust, but it you might loose a little sucking power with that long path.


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## TheTiddles (31 Jan 2010)

Not that it makes much difference, but you won't have laminar flow (where all the air is moving parallel to the pipe sides) anywhere in any dust extraction system. The summary of how the particles are dropped from the air flow is right but the energy loss in doing it is huge comparred to a cyclone system. Whilst these box thingys look like a nifty way to spend a few hours, is emptying your extractor so hard?

Aidan


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## woodbloke (31 Jan 2010)

TheTiddles":2ptkntmf said:


> Not that it makes much difference, but you won't have laminar flow (where all the air is moving parallel to the pipe sides) anywhere in any dust extraction system. The summary of how the particles are dropped from the air flow is right but the energy loss in doing it is huge comparred to a cyclone system. Whilst these box thingys look like a nifty way to spend a few hours, is emptying your extractor so hard?
> 
> Aidan


Agreed Aidan, it's not hard to empty the extractor. The main benefit though is that the filters in the vac won't get clogged as all the dust will be in the box, not caked on the outside of the paper filter, in which case losses will be just as high...I think - Rob


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## Mr Ed (31 Jan 2010)

TheTiddles":fj1zvzjc said:


> is emptying your extractor so hard?



Well I've been wondering the same thing. If you suck up a Kilogram of dust, its a kilogram wherever you empty it from. I don't see why its any more trouble to empty it from the extractor than it is to empty it from a wooden box.

Maybe I'm missing something...

Ed


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## MikeG. (31 Jan 2010)

What you are missing is really 2 important things:

1/ the box can hold many times as much dust as your extractor can

2/ by preventing dust getting to your extractor, you prevent any getting into the air. It isn't dependant on a filter to keep the air clean.

Mike


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## woodbloke (31 Jan 2010)

Mr Ed":6s9oyuhm said:


> Maybe I'm missing something...
> 
> Ed


Not only is it the filters (see previous post) but you could make a box that could hold a lot more than the 90L capacity of the C386, which we both have
Edit - dropbox guru and world supremo beat me to it :lol: :lol: - Rob


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## DavidE (31 Jan 2010)

woodbloke":pfn0def8 said:


> TheTiddles":pfn0def8 said:
> 
> 
> > Not that it makes much difference, but you won't have laminar flow (where all the air is moving parallel to the pipe sides) anywhere in any dust extraction system. The summary of how the particles are dropped from the air flow is right but the energy loss in doing it is huge comparred to a cyclone system. Whilst these box thingys look like a nifty way to spend a few hours, is emptying your extractor so hard?
> ...



From my point of view the RSDE1 dust extractor design is such that the dust enters the drum in line with the filter so a lot of it hits the filter straight on. Therefore, I invariably spend quite a lot of time lifting the lid up and brushing the filter down (not necessarily emptying the extractor). So although I've not used mine long term yet I envisage I will spend less time doing this and introducing dust into the air. I was concerned how lossy it would be, however, from my initial tests it's not bad and the average level of suction will increase as it won't rely on me going and clearing the filters. 

Cheers
David


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## sometimewoodworker (1 Feb 2010)

Mr Ed":1xee9meg said:


> TheTiddles":1xee9meg said:
> 
> 
> > is emptying your extractor so hard?
> ...



That will depend on your extractor. 

In my case my CT22 uses bags at a bit over a fiver each as well as filters and so far I am still on the first bag after about 3 years. 

I would guess there is may be 1/2 a liter of dust in the bag and none on the filters.

Right now I've probably saved myself something north of a hundred quid.


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## Qwibble (1 Feb 2010)

TheTiddles":1h0a9q7h said:


> Not that it makes much difference, but you won't have laminar flow (where all the air is moving parallel to the pipe sides) anywhere in any dust extraction system. The summary of how the particles are dropped from the air flow is right but the energy loss in doing it is huge comparred to a cyclone system. Whilst these box thingys look like a nifty way to spend a few hours, is emptying your extractor so hard? Aidan



I totally agree that I won't achieve laminar flow, but minimising turbulence should help to some degree. Don't know how much difference it'll make, but I've got a black bin and a Henry, and enjoy a challenge (trying not to burn my fingers with the glue gun).
I extract my routers/sanders straight into Henry at the mo. So I'm hoping the bin would reduce the number of dust bags I get through.

I've had a look a some DIY cyclones but I have to admit I don't yet understand them. :? That might be project #2


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## woodbloke (2 Feb 2010)

The O's has been fitted and tested. Everything is airtight and the inlet tube from the vac to the box is squashing up nicely, so no leaks.

However, resluts are dissapointing  The big stuff is getting stopped nicely but the smaller, fine dust is still getting through to the vac. I cleaned it out thoroughly and put on a new paper bag. Holes in all the baffles are 6mm thick...any suggestions Mike? - Rob


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## Mr Ed (2 Feb 2010)

woodbloke":2mnml3rb said:


> Not only is it the filters (see previous post) but you could make a box that could hold a lot more than the 90L capacity of the C386, which we both have



I emptied my Camvac, for the first proper time since I bought it, at the weekend and found it about 1/4 full, with relatively little on the cloth filter and nothing on the paper filters. I still use my ADE1200 for planer chips, so the 386 is for fine dust only. In my hobby environment it appears I can go some considerable time without filling it so I will stick with that.

I'm sure the dropbox concept is a good one, I just don't think I need it.

Ed


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## woodbloke (3 Feb 2010)

At Mike's suggestion, I've put in severial new baffles with smaller 3mm holes (and less of them) but it doesn't make any difference...my WV1000 just produces too much suck to stop the finer dust from being drawn through to the vac canister. No room either in it's present location to build a bigger box, which is what Mike suggested.

So on this occasion, it's a 'wrong bong'  - Rob


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## wizer (3 Feb 2010)

I wonder why this works for some people and not for others. It appears to me that Mike may have got his design spot on first time without realising it. You may have to keep tweaking the design til you get it right, Rob.

Personally, I think I'm going to go down the cyclone route when\if I ever get there.


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## DavidE (3 Feb 2010)

woodbloke":30g5cw8c said:


> At Mike's suggestion, I've put in severial new baffles with smaller 3mm holes (and less of them) but it doesn't make any difference...my WV1000 just produces too much suck to stop the finer dust from being drawn through to the vac canister. No room either in it's present location to build a bigger box, which is what Mike suggested.
> 
> So on this occasion, it's a 'wrong bong'  - Rob



Rob, if you suck a pile of dust up - how much gets through (rough %) and what size would you say the smaller particles are that break through?

Wizer - it is highly dependant on flow rate and the design. It's a bit of a black art. I was reading a textbook yesterday talking about the designs of these systems and the volumes they were suggesting you needed for fine particles were pretty crazy. (When I finish it off I will post some calcs for Mike's box and my own version)

Cheers
David


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## woodbloke (3 Feb 2010)

DavidE":2lebhesl said:


> Rob, if you suck a pile of dust up - how much gets through (rough %) and what size would you say the smaller particles are that break through?
> 
> Cheers
> David


I put say a *large* jam jar full of sawdust (Haywards pickled onion size) through and of that, a cupful of finer stuff (like flour) was in the bottom of the vac bin and coated round the paper bag, which is not satisfactory. If a much less powerful vac were to be used (as in Mike's original) then nothing gets sucked through, which is as it should be, but with a powerful sucker, the problems seem compounded - Rob


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## DavidE (3 Feb 2010)

woodbloke":1v3tuntm said:


> DavidE":1v3tuntm said:
> 
> 
> > Rob, if you suck a pile of dust up - how much gets through (rough %) and what size would you say the smaller particles are that break through?
> ...



Flip! What is the flow/power rating of the high powered one?

I wonder if it worth trying it with one of the upper sections removed and a deflector put in to stop the flow short circuiting. The other thing that might work is putting a baffle over the holes between sections and take the baffle plates out you have now. (hopefully you can see what I mean in this picture, I also tried to get the flow to snake round.

I suspect on a similar test with mine I'd get less than a tea spoonful of very fine dust (keeping the cooking sizes going!)

David


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## woodbloke (3 Feb 2010)

The whole idea has now been binned and I've connected the vac directly to the K419...time to start making things instead of ar$ing around - Rob


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## wizer (3 Feb 2010)

I think that's probably a good idea. These drop boxes are probably more trouble than their worth. I've had my RSDE2 for four years and I've changed the filters about once every two year (it need changing now).


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## DavidE (3 Feb 2010)

woodbloke":3f13qohp said:


> The whole idea has now been binned and I've connected the vac directly to the K419...time to start making things instead of ar$ing around - Rob



Oh dear the dreaded bandsaw  

It's a shame you've given up... remember it took Dyson 5127 prototypes to get his product to market! I made mine with the intention of having to tweak it - hence the clear front. unfortunately, fluid flow is a bit of a black art especially with all the turbulence so fettling is needed.

Wizer - I guess it depends what dust your processing. I've needed to change the paper filters a lot more often than I'd like on the RSDE1s I've got and also been narked by how quick they blind - wishing they had a blow back system.

Cheers
David


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## wizer (3 Feb 2010)

I've been using the cloth filters. I had the .5 micron one for MDF on but it made a significant reduction in flow and was a puppy to clean. So I took that out and just have the corrugated paper one and the cloth that covers it. I just vacuum it every time I empty it.


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## DavidE (3 Feb 2010)

wizer":1b8u6w94 said:


> I've been using the cloth filters. I had the .5 micron one for MDF on but it made a significant reduction in flow and was a puppy to clean. So I took that out and just have the corrugated paper one and the cloth that covers it. I just vacuum it every time I empty it.



Okay - I tend to brush the filters off when emptying. I've found when using Oak or Sapele they coat up really quick so I'm brushing them off well before the bin needs emptying. If your vaccing them off where's that dust going and what happens to that filter! 

David


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## wizer (4 Feb 2010)

I use the Henry to vac it off.


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## woodbloke (4 Feb 2010)

DavidE":2wp3pvw5 said:


> Oh dear the dreaded bandsaw
> 
> It's a shame you've given up... remember it took Dyson 5127 prototypes to get his product to market! I made mine with the intention of having to tweak it - hence the clear front. unfortunately, fluid flow is a bit of a black art especially with all the turbulence so fettling is needed.
> 
> ...



No, not this time...it's just been dumped outside the workshop, ready for the bin men. I was happy to have a little play with it to see if I could get it to work, but I haven't got the patience for this endless tinkering and my 'shop is for making furniture. I know that Mike advoctes a rough and ready approach to the build, but the constant use of a 'hammer and nail' to make it was starting to irritate :x It would be very useful if we could have some sort of rule, or ref guidlines on flow rates and suitable sizes of sucky machines and boxes etc - Rob


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## big soft moose (4 Feb 2010)

woodbloke":3qpuqx4l said:


> DavidE":3qpuqx4l said:
> 
> 
> > Oh dear the dreaded bandsaw
> ...



reading this with interest as i had thought avbout one of those drop boxes for work (not enough space in the home shop) , however like you i have limited patience for faffing about and want to be actually doing the job.

i think we'll look at a cyclone - though we may just wind up buying something like the dust gorrila to replace our DX5000 if space and budget permit.


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## miles_hot (4 Feb 2010)

big soft moose":34hohbj9 said:


> woodbloke":34hohbj9 said:
> 
> 
> > DavidE":34hohbj9 said:
> ...



Thanks to some of the people on this and the other thread I have been doing some numbers and I fear that I may end up with a pretty massive box (some 2'x3'x5-6') and I'm still not sure that this would provide just the turbulent area or include the dust collection pod. At this point the size becomes an issue and I'd be better off with a cyclone.

I was going to get a gorilla however I've now got a fox 3hp collector so I have the motor and impeller so it's home made cyclone time (oh joy) however I have got the details of the Donaldson filter and I think that it will be enough to buy just one.

I think I still need to do some calculations etc and get off the fence - also have to find some time to actually go out into the garage to make the thing. I suspect that I may end up getting a small shop vac for the small diameter hoses element as whilst I'm pretty sure that the fox would be able to cope I think I remember someone saying that small hoses can cause the cyclone to stall dumping all the dust onto the filter which is what I'm trying to avoid. Thus there could be a use to having one of the original Mike design / size boxes for the shop vac - pr maybe just use a dyson cyclone.... Oh, I don't ruddy know! 

Miles


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## big soft moose (4 Feb 2010)

miles_hot":3e8l5w32 said:


> Oh, I don't ruddy know!
> 
> Miles



thats the good thing about your project managers - the razor sharp decisiveness  

my suggestion would be to ebay the fox bits and just buy a dust gorrila from onieda if you can afford it - if you only have limited time in the'shop you want to be spending it woodworking not faffing about fine tuning a home built rig


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## Harbo (4 Feb 2010)

Slightly off thread but has anybody used the Dust Deputy?

Rod


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## miles_hot (4 Feb 2010)

big soft moose":2bvug9xb said:


> miles_hot":2bvug9xb said:
> 
> 
> > Oh, I don't ruddy know!
> ...



When last I looked at the gorilla it was the thick end of £1200 - 1500 and the fox only cost me £270 so I've got some way to go yet. It's possible I will end up at that space and whilst I don't have that sort of money at the moment if I need to spend that sort of cash I will to protect the health of all concerned.

In the mean time I'd like to try to avoid spending that much as I also want a Jet 310 this year - and that's not a safety critical purchase and so has to go through a significantly more arduous spend approval process 



Miles


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## sometimewoodworker (5 Feb 2010)

Harbo":1w1uv4ki said:


> Slightly off thread but has anybody used the Dust Deputy?
> 
> Rod


I use the Clear Vue. However the DD is just as good.
There is more info here https://www.ukworkshop.co.uk/forums/under-development-garnham-style-dropout-boxes-t38213-60.html


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## Doug B (5 Feb 2010)

Harbo":1l153p0c said:


> Slightly off thread but has anybody used the Dust Deputy?
> 
> Rod




Bought one 2 years ago, & i wouldn`t be with out it.

It`s hooked up to my Camvac, is easily portable (for sanding floors on site) & means i very rarely have to look inside the Camvac.

Easily paid for itself.


You might get the idea i really like it, :lol: :lol: :lol: :lol:


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## big soft moose (5 Feb 2010)

miles_hot":ao1ya3p9 said:


> as I also want a Jet 310 this year - and that's not a safety critical purchase and so has to go through a significantly more arduous spend approval process



you need to discover that its "essential" for some job that needs doing arround the house - then ask for spend approval on a really expensive model - when thats rejected you can say "yes dear" and go away and find the, cheap by comparisson, 310 as the "budget" option

I find this physcological model also works quite well with senior managers


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