Thread: ClearVue installation with Auto Blast Gates

Having now watched many videos and looked at various posts, I've come up with an SCMS cabinet design which I think will do the job: keep fine dust out of the shed. The idea is to create sufficient negative pressure inside the cabinet to draw any fine dust particles into the outlets. The size and shape is intended to fit a Makita 1019 SCMS.

There'll be two outlets. One full width 125mm deep channel across the rear floor will incorporate melamine ramps sloping down to a flat plate in the centre with a 100mm BMH outlet. The other outlet will be set into a sloping roof close to the rear. Both outlets will be joined by a 45 degree elbow and connected to the 150mm line with an auto blast gate where it meets the 225mm main line.

SCMS Cabinet - Plan View.jpg SCMS Elevation.jpg

mick

With the (almost) completion of the mitre saw cabinet, that's the whole workshop done, except for a portable stand and BMH for jobs like drilling, jigsawing etc. which throw their fair share of sawdust. I discarded the idea of a benchtop cabinet and went with one on a separate frame made to the height of my main bench. For ease of joinery I used 42x90 finger jointed pine with the top rails bridle jointed along the front and through tenoned at the sides. The lower rails are lap jointed with side rails through tenoned. I added a through dowel to all joints just for fun. The frame is as solid as...

Attachment 470019 Attachment 470020

First I built the rear outlet incorporating melamine ramps sloping down to a 100mm outlet with a mini wooden BMH 125mm diameter.

Rear Outlet before fitting.jpg

The floor, walls and roof, all 19mm plywood, came together pretty easily although shaping the outlet though the roof proved challenging. To end up with a vertical 150mm stack for ease of connection to the ductwork, and for looks, meant that the hole in the ply had to be elliptical with a gradually steepening angle from front to back. I cut a piece of 150 pipe at 31 degrees to trace the outline of the hole and set to work with the jigsaw. It took some perseverance but eventually I had an opening which would fit and filled the gaps with silicone. Two more pieces of ply were added and screws inserted for strength and stability. Once again, the opening was enlarged and radiused.

Interior of cabinet.jpg

With the cabinet frame built, I needed to plumb the bottom pipe through to the top of the cabinet to connect with the top outlet and on to the overhead ductwork; and I want it to look elegant (if that's the right word). Fortunately I'd allowed for a shelf on the left hand side so running a 100 pipe up through the shelf seemed like the better solution.

Rear view of cabinet.jpg


A quick check with the mitre saw in place confirmed that it could be used in all positions.

Right 45 degrees.jpg 90 Degrees.jpg Left 45 degrees.jpg

A few jobs remain before the testing phase. I need to cut a hole in the rear for the cord and make a space in the workshop as a permanent home. The height of the plate is coplanar with my main bench so that's where it'll go. That means unloading the cabinet in that spot and moving it away. Then I need to run the ductwork across before I hook it up for the acid test.

I might add that none of the ply is glued, only screwed. Which is what I'll be if the whole design proves a failure. Here's hoping.

mick

Well done Mick, a marathon effort!

Rather than cutting the flexi to length prior to testing, I thought it wise to make sure the thing worked first before committing.

Temporary connection to ClearVue Max.jpg

The objective is to create negative pressure inside the box sufficient to prevent the escape of any dust particles. That meant testing the entire open area. BobL had suggested using fine cotton telltales which did work quite well but were impossible to photograph other than in close up. So I went back to the candle. Rather than post about 12 photos of it in different positions, a couple should suffice.

The candle is midway up the opening about 300mm outside the box in this pic. Candle test outside cabinet.jpg

This one is about as close as I could get without the candle blowing out. Candle test closer in.jpg

After about ten test cuts, coarse sawdust still settled on the areas behind the fence. A quick puff of breath with the dusty still running was enough to make it disappear.

The cabinet design passed with flying colours. I doubt you would get the same result with a smaller dusty but there's plenty of space in the open side to be reduced if necessary.

Now I can finally get back to making furniture...

mick

Great job and great thread Mick! I only just saw it this morning (been AWOL doing a round of panic soup making).

Very instructive for anyone wanting to do a very effective DE installation.

Originally Posted by QC Inspector

A small improvement to your slots would be to round over the edges with a rounder bit. Bob would be able to say if just doing the outside with a bigger bit is better than putting a radius on the inside and outside of the slot. Basically "bell mouthing" them.

Pete

Sorry Pete, I forgot to respond to your suggestion. I imagine the airflow is now improved and it sure looks better now than previously. A picture tells a thousand words...

Radiused Router Table Inlets.jpg

mick

To pick up more chips a BMH can be placed right where the max amount of chips strike the back of the main hood. that way the stuff is being fired close to where the max air speed is achieved.

Originally Posted by BobL

To pick up more chips a BMH can be placed right where the max amount of chips strike the back of the main hood. that way the stuff is being fired close to where the max air speed is achieved.

That's probably valid for a lot of mitre saws. However the Makita 1019 has a rubber boot directly behind the blade which feeds into flexi and connects at the bottom rear with an outlet approx. 40mm i.d. It does a pretty good job of collecting the bulk of the sawdust but not all of it. The outlet is positioned directly above and pointing down into my 100 outlet.

mick

Responding to the request by Tonyz, here's what's been happening since my last post. The idea behind the cabinet was principally to trap most, if not all, the small particles of sawdust.

The first improvement involved adding "wings" to the top open corners. It stands to reason that reducing the open area would increase airflow from outside. They'll have to be modified down the track to enable a full tilt of the blade. I hardly ever need this so I'm happy for the time being.

SCMS Cabinet Wings.jpg

The Makita has a rubber boot behind the blade which is flexi-piped to an outlet at the back of the saw. I made a female fitting to suit with a piece of 40mm PVC pipe and a heat gun. The i.d. of the pipe is perfect female fit for bog standard cheap 40mm o.d. flexi. I've done no more than put the loose open end of the flexi down into the floor outlet. The induced vacuum down inside the pipe is quite sufficient.

Rear exhaust outlet of Makita SCMS.jpg

The Makita High Fence creates a "lee shore" preventing a lot of the dust thrown around by the blade in the front. It also has a very small gap around the blade which doesn't work that well when a wide piece is being cut. Most of the time I don't need it so it was put aside. Even with the shorter fence some dust still accrues.

Makita SCMS High Fence.jpg Makita SCMS Low Fence.jpg

This is not a big deal because my candle tests in an earlier post indicate an area of negative pressure about 200mm in front of the open side but it can affect the accuracy of subsequent cuts so I used another length of 40mm flexi and shoved it down the pipe in the floor. I use this to vacuum up the sawdust which lands around the deck of the saw and behind it.

Vacuum hose for general cleanup.jpg

Some designs extend the side walls out further than I have. It really depends on how powerful your dusty is.

Hope this helps. Good luck building yours!

mick

thanks Mick, your last pic is wierd...I was dreaming about that last night and didnt get time today but am hoping I could push a bit of hose up into the 'arm' that the blade can cut into. to make that clearer..hopefully
The is a small trench the blade swings into, not deep enough to cut, Its on the bar that marks your cutting line. I wonder if I could have holes inside that and a hose sucking from under...

Yes, sorry Tony. I missed showing the loop in the pipe. It's no more than a piece of flexi shoved down the back outlet, the open end of which I use as a vacuum cleaner.

Most of the dust is picked up in the gullets of the blade and maybe a slot under the blade would be useful. It depends on how grunty your dusty is. What sort of mitre saw are you using and how big is your dusty? Quite a lot of dust gets thrown out to the side, especially on very broad planks. Those photos of the fences were taken after 6 cuts through a piece of 200mm fascia 19mm thick.

The Kapex has the best dust system but I couldn't bring myself to spend an extra grand just to collect a bit of stray dust around the cabinet when the it sucks in most if not all of the dangerous stuff anyway. I'd rather not develop emphysema.

mick

this may sound totally stupid but thats not unusual with me. For behind the SCMS I am hoping to make a fibreglass mold in the shape of a Weber kettle lid, once Ive got that I shape a 150 bell mouth into one 'side' and encase the rest.
The reason...being the semi round shape there are no dirty corners for dust to settle, and when power stops the remaining dust/chips fall into bell mouth.
Fair go sometimes I amaze myself with the stupid ideas I come up with.

wish me luck.

My Carbatec table saw has no overhead vacuum outlet for dust collection so I decided to try a 150 bell mouth hood mounted above as an alternative. It's early days yet, but it appears to collect >95% of the dust which would normally remain on the table after each cut. There's a 90 degree elbow above which allows me to swing the pipe aside when I'm setting up the cut.

My ClearVue has enough enough grunt to handle the additional open gate so maybe it wouldn't work quite as well with a less powerful unit.

Table Saw Overhead Dust Capture.jpg

mick

Hi Glider

a couple of questions about your dust bin and cyclone

my CVmax arrives next week so am in the process of designing my waste collection bin. I currently use plastic bags on my twin dusty and when they are full I have heaps of locals who take the bags for there gardens and chickens etc, so I’d like to keep using the bags on the Clearvue.

does your dust bin take a plastic bag?

my little cyclone unit from Hare & Forbes has a hose that goes from the cyclone to the bottom of the collection bin and i use plastic bags on that, I’m assuming that’s to equal the pressure and stop the bag from being sucked into the cyclone.

also what did you use as a reducer from the 225mm pvc ducting to the 200mm inlet on the Clearvue?

also,did you glue your pvc ducting or dry fit and use tape to seal it?

cheers
Paul