Dust Extractor

[Mayo Dave]

Hello new member here. I've just expanded the workshop which is great, and trying to improve dust extraction and improve housekeeping
I've got a Record dx5000 wall mount extractor which is great. dedicated to table saw at present. I actually added another port to the extractor so now I have one post extracting from the crown guard and the other port extracting from the blade 'guard' or collector (inside the machine)
I piped the blade guard directly out of the side of the table saw, as originally the blade guard piped to the bottom of the saw.
there is still a lot of dust inside the machine. an old tecnica s300 panel saw that I inherited

The blade guard is 4" flex house directly to the extractor.
The Crown guard is 2.5" flex Hose which is connected to a reducer just outside the extractor

so im wondering a few things
on the crown guard pipe. should this be 4" pipe to the extractor instead of 2.5". I read recently that on High volume, low pressure extractors that you should not reduce the pipe size u til you are almost at the tool

I'm thinking of putting in a cyclone. simply as when it comes time to empty the bag, and check the filters, the dust inside the extractor hood is hard to deal with. I know that with a cyclone the dust to the e

 

[Mayo Dave]

... extractor will reduce, and therefore easier to clean extractor. the cloth bag will be much cleaner. anyway. Ihave heard that introducing a cyclone may significantly reduce volume throughput?

ultimately id like to extract from the crown guard, blade 'guard' and bottom outlet of saw. this will probably mean a mini sewer piped system and possibly a bigger extractor

looking for some inspiration
thanks

 

[Inspector]

Welcome to the forum. Lots to learn here.

What you are planning to do won't work as you hope. Go back through my past replies to similar questions. Click on my name above my Avatar to find them. It'll save me a long session of one fingered typing. Meanwhile wear a good respirator.....if you can find one these days.

Pete

 

[Chippymint]

... extractor will reduce, and therefore easier to clean extractor. the cloth bag will be much cleaner. anyway. Ihave heard that introducing a cyclone may significantly reduce volume throughput?

ultimately id like to extract from the crown guard, blade 'guard' and bottom outlet of saw. this will probably mean a mini sewer piped system and possibly a bigger extractor

looking for some inspiration
thanks

Hi Dave. The subject of dust control is endless and I'm sure you will get a few replies.

It's normal to have a large diameter hose/pipe connection to the main cabinet (4/5/6 inch) and then a reduced size connection to the blade area (3/2.5/1.5 inches). Their sizes are normally recommended by the manufacturer. It's important to be aware that in order for this to be effective, you will need an extractor and system capable of meeting their extraction rate normally quoted as Cubic Feet per minute (cfm).

Workshop extraction is key to your health so getting it right is a good move. You can spend a lot of money trying to get this right. Don't worry about cyclone systems at this stage, learn about the subject matter and you will soon have a proper plan and one that will achieve your long term goals. My recomendation is do some research on dust extraction and you will be pleasantly surprised at how good the results are. A good book is Woodshop Dust Control by a guy called Sanfor Nagyszalanczy.

Hope this helps and come back to me if I can help further. Cheers Steve

 

[DBT85]

The dx5000 is a hplv vac so you don't need to worry as much about reducing it down. A cyclone will also have less suction loss on it than it does on a lphv extractor.

Bigger pipes will better but you're still limited to the 100mm inlet in your vac.

 

[Inspector]

Sandor actually wrote 2 books. Dust Control Made Simple is the other. Problem with them is they (as are most of the published books aimed at small shops) were published 18 and 20 years ago so some of the information in them is dated and that should be kept in mind. Many of the airflow recommendations people reference are from standards up to 60 years ago when the goal was to keep the sawdust from piling up everywhere, not necessarily to protect our lungs. They were concerned with the dust that could be seen. The dust you can't see is where the danger lies and that is harder to deal with as it requires high volumes of air to capture it. The guys are right in that research is needed to understand dust collection. It seams like it should be simple but it is one of the most difficult parts of woodworking to get right.

Pete

 

[Mayo Dave]

thanks for the swift replies.

dbt85
I thought dx5000 was high volume low pressure. shows what I know! if it's high pressure low volume what type of unit would be high volume low pressure for example ?

Steve
I eventually got the manual for the saw from Italy. I can't find the recommended cfm though.
it is a fairly typical panel saw. about same size as say a record ts2. single phase.
if any of you can suggest a comparison cfm, I can then size what id like to do, which is three take-offs from the saw.
I can see that the cfm on the record dx5000 is 222. for comparison the axminster cyclone unit ac118ce is about four times that on 4 inch hose. about 5 times on 5 inch hose.

Oneida Google search says 450-800 cfm for a 10 inch saw with 'top guard'. so it looks like dx5000 will not do the job [at all!]

I'm prepared to invest in extraction unit up to and including ax ac118ce. possibly Laguna pflux.

 

[DBT85]

A LPHV generally looks a bit like this in different sizes. They scream a bit less than your dx5000 and my dx4000, can shift a lot more air but cannot cope when they are restricted down to smaller diameter pipes or have long runs with flexible pipe that will sap airflow. Indeed another issue is that when they just have these bags on as shown in the image they only really stop large chunks getting out. They let through streams of sub 5 micron material which is the more dangerous stuff. You can replace those bags with better filters which will filter out everything down to 1 micron. The specifics of what each can filter down to are sadly often not published. Your DX5000 will have quite good filtration of small particle like that, but it won;t be catching nearly as many in the first place which another problem.

In an ideal world we'd be able to hook up a 5hp 150mm hose to every tool, but cost, space and form factor limit that considerably. It might make a tracksaw a little unwieldy for example!

Have a quick watch of this from Wandel, he shows the effect on suck and airflow of pipe diameter and length on a shop vac (basically the same as yours and mine but with a smaller inlet) and a machine like the one above.



Ideally you'd have a decently sized unit with 100-150mm rigid pipe, and a short run of flex pipe going up to the underside of the blade/cabinet and one going to the guard.

Do remember of course that if you fit a 100mm hose up to the underside of the saw but the only hole for air to get IN is around your zero clearance insert, you're choking the system as a 2mm slot that's 300mm long only has an area of 600mm2 (further restricted by the blade being in the way), compared to a 100mm hose which has an area of 7800mm2.

Have a look at Dennis efforts to increase the airflow through the zero clearance insert

 

[Mayo Dave]

thanks for all that
Im going to look at a 6" inlet on a minimum 2hp, 1 micron extractor.
Then look at 6" sewer pipes for a mini pipe system

The axminster craft cyclone ac118ce has an annoying 5" inlet. Which I guess should not be connected to 4" or 6" pipe?
Its 1675 m3/hr which is just shy of 1000 cfm which is good. 2hp and 1 micron
Its their craft model, and the cheapest ive seen on the market, so im not sure on the build quality

their trade cyclone at176ceh is three times the price! but is .3 micron, 2hp and about 1000 cfm on a 178mm inlet

Their at170e trade bag extractor is 7", with 2250 m3/hr, which equates to 1300 cfm, which is definitely in the region i need. Its 1 micron cartridge and 2hp
Could this be hooked up to a 6" sewer pipe do you think, or should it only be matched to 7" pipe, which I dont know if available?

is 1 micron going to cut down on very very fine dust. i dont machine mdf, except very rarely. But i do machine native hardwoods a good deal.

i have a zero clearance insert set, but the video you posted is very good. i will look into that more

yet another question
if i was to have an extraction unit in the middle of a long 30ft wall, with say table saw to left and mitre saw (or planer or whatever) to right; how do you duct to both left and right - ie at some stage there needs to be a u-turn to get to either left or right. most of the units that i look at seem to be left-handed, or the inlet is on the left hand side - how do you get to the right without creating too much drag in the pipework.

anyway I appreciate your comments, thats why I joined the forum. Im in the far west of ireland, so not much chance to discuss this in a tool shop!

Dave
[excuse the typos]

 

[Inspector]

I'm a little sceptical about some of the airflow claims of those machines. For one you can only pull 400cfm at most through any 100mm/4" pipe. The other thing is many of the manufacturers test the DC with just the impeller and housing, no fittings, filters and just a short test duct. They take a single reading in the centre of the airstream and put that in the specs. When the DC has all the gear on it and a duct to the machine it will actually be about half as much.

A 2 hp DC will work with 6" duct as it is unlikely going to exceed the flow capacity of a 6" duct which is 1,200cfm at the most. With a 2hp DC using 6" ducts you should keep your runs as short as possible and with as little flex as you can get away with. Flex has 3 times the drag as smooth. 7" metal pipe is fairly common here but I don't know what it is like in your region.

Splitting the air to the left and right of the machine is problematic with the neatest solution being a "pants" fitting. They aren't made in PVC and are custom in a spiral metal duct. You would have to look for a wye and add more fittings until you have looped back the other way. Blast gates placed to shut off the side not being used. Large radii fittings to minimize the drag. There will likely be too much drag configured like that.

Pete

 

[Doug71]

These guys are good for pipe, ducting and fittings once you need anything above the common 4" plastic fittings. You mention using sewer pipe, I am always surprised how reasonable the proper metal ducting is.


https://www.dustspares.co.uk/?gclid...nfYXxR8rlBujJpsoKj31VIR1laQR1tgxoCDfIQAvD_BwE

 

[DBT85]

Have a delivery coming from them today in fact.

The problem is @Inspector that you can go so far down the rabbit hole and still never get to the point where you have a perfect system. The safest bet is to assume that you always need a mask anyway and then do what you can with the extraction to have space for or can afford.

I'm tempted to buy a amemmeanaometer (sp? ) and do some tests of my own. Sadly its not something anyone has really covered well on the youtubes, its all large tombs with old specs and standards.

 

[artie]

I'm tempted to buy a amemmeanaometer (sp? ) and do some tests of my own.

I bought one about 5 years ago, full of big ideas and enthusiasm.

It's still in the box.

 

[Inspector]

Have a delivery coming from them today in fact.

The problem is @Inspector that you can go so far down the rabbit hole and still never get to the point where you have a perfect system. The safest bet is to assume that you always need a mask anyway and then do what you can with the extraction to have space for or can afford.

I'm tempted to buy a amemmeanaometer (sp? ) and do some tests of my own. Sadly its not something anyone has really covered well on the youtubes, its all large tombs with old specs and standards.

Yep I know but if one is going to do it they might as well do it right. It's all about lots of airflow to capture the fine stuff and most people are unable or loath to go that far.

The little beastie you want is an Anemometer for measuring the airflow. There are three kinds. Fan, hot wire and pitot static. The fan type you see depicted on so many YouBoob videos is the wrong type for our uses. The size of them makes the air speed up to get through and around them. That makes them read high 30% or more. The hot wire type is a little more money but because of the small rod/probe doesn't disturb the air like a fan type does. The pitot static anemometer is the best but costs more again. Tests should be done across a test duct, the multiple reading giving an average for the duct. The test duct is simply a bit of duct 5 to 10 diameters of the duct long with a hole in the middle for the probe to fit in. A straight length of your system will serve unless you want to take readings at different locations. You want an anemometer that can read up to 30m/s. This is something like what I'll buy when I get to that point. Anemometer - Buy Thermoanemometer,Anemometer Price,Air Velocity Meter Product on Alibaba.com A particle counter is a nice companion tool as it will show you when you should be wearing and more importantly remove your mask. They don't cost much anymore either. There more than you wanted to know.

Pete

 

[DBT85]

Never Pete I love to add new into to the arsenal!

How does the pitot staic measure correctly when speeds are different in different parts of the duct (slow sidewall air vs fast core air)

I bought one about 5 years ago, full of big ideas and enthusiasm.

It's still in the box.

I have 4 stainless steel bbq burners that I bought to replace the ones on mine that had rotted. They are still in the box of mastic tubes I put them in 3 years ago!

 

[Inspector]

Never Pete I love to add new into to the arsenal!

How does the pitot staic measure correctly when speeds are different in different parts of the duct (slow sidewall air vs fast core air)

You average a number of readings across the duct. The probe has to be accurately spaced at intervals across the tube with the pitot static tube aligned in the duct, each reading taken, totalled and averaged. Another method if you have the right instrument is a timed traverse across the duct and the instrument totals the readings as you traverse the duct and gives you the average. Yet another way is with a pitot static manifolds. They have ports across the tube and when connected to the instrument automatically average the readings. Have a blast reading.

https://static-int.testo.com/media/...00-Practical-Guide-AirFlow-Measurement-EN.pdf
http://www.rses.org/assets/serviceapplicationmanual/630-104.pdf
https://www.trutechtools.com/Measuring-Airflow-with-a-Pitot-Tube_c_253.html
https://www.tsi.com/getmedia/668b4c26-9783-4bc8-9dd3-c921b557bf71/how_to_determine_air_flow?ext=.pdf
https://www.fluke.com/en-ca/learn/blog/hvac/duct-traversal-airflow-measurement
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.511.9635&rep=rep1&type=pdf
Pete

 

[MikeK]

Here's a 13-minute video that does a good job of describing the pitot tube method. I was considering a hotwire anemometer, but after watching this video, I bought a Dwyer 477AV-2. I don't want Bill (from the video) breaking my fingers.

 

[Mayo Dave]

Sorry. On another note. A slider saw has come up for sale here in Ireland. Minimax sc3w. Any thoughts, as the price is good 1750 ex vat.

 

[MikeK]

Sorry. On another note. A slider saw has come up for sale here in Ireland. Minimax sc3w. Any thoughts, as the price is good 1750 ex vat.

There were two versions of the SC3W. One had a sliding wagon travel of 1600mm and the larger version had a sliding wagon travel of 2250mm. The smaller version later became the SC2 Classic, which is what I have, and the larger version became the SC3 Classic. If the SC3W is in good condition, the price of €1,750 is reasonable, and is less than half the price I paid for my saw over three years ago.

If you have a chance to look at the saw before you buy it, make sure the slider wagon bearings are smooth and don't grumble as the wagon is pushed along the track. If there is noise from the bearing track, this could be a very expensive fix if parts are still available. The saw is heavy and has a concrete counterweight to compensate for the outrigger.

 

[Mayo Dave]

I am waiting for more pics. The saw is about 150km away, and with COVID19 restrictions in Ireland, I cant go to see it right now.
I think its the shorter version slider. Does 1600mm mean you can cross-cut 1600mm?
Can you send me some pics of your saw and I can compare to the pics that I get?
I believe that the spindle is not on a trunion - just wondering what that effectively means
Thanks, appreciate it
Dave