Dust Extractor - are the blowers all pretty similar?

[Aidex]

Hi Everyone

Work and the arrival of little man no. 3 have kept me from just about anything including internet and woodworking for a while!

I bought a table saw about 6 months ago (Axminster 10”) that I’ve not had a chance to plug in yet much less use. I work in a front room of our house but with the little ones I’m worried about using the table saw without extraction (for my other (smaller) tools (router, TS75, etc) I use a vacuum extractor). Eventually I’ll build a small workshop in the garden (I hope!).

I don’t own a chip collector/extractor and would like to get one that I can use now with the table saw and eventually use for a ducted system in the workshop (planning about 30m2 when it eventually happens).

At the minute I don’t have much space but i just want to use the impeller with a 6” Dust Deputy cyclone (or should I make my own?) and duct the waste/exhaust air (fine dust) outside (ie loose the bags/filters, etc). Later I’ll either duct outside again or house the extractor with filter/bags and cyclone in its own (external) “room/shed” behind the workshop.

Because I don’t know what additional tools I’ll buy in the future I thought to buy as big an impeller as possible in 240V. 3HP (2.2kW) seems to be the biggest single phase I’m finding but I don’t understand the different specs between manufacturers. Some have big differences in quoted volume of air movement, static Pressure, etc and none seem to quote air speed. Can I assume that at 3HP they’re all pretty similar in terms of performance (ignoring that some may have better quality motor, quieter motor etc)?

I was leaning towards the Axminster trade 3HP blower:

https://www.axminster.co.uk/axminster-t ... tor-102179

But I’ve seen Fox, Charnwood, Clarke and other significantly cheaper units with 3HP blowers mentioned and wondered if I would lose anything in terms of performance if I went for one of these? Saving up to 2/3 the cost of the Axminster one is a lot but I’m happy to spend it on dust extraction more than any other tool if it will make for a cleaner (and safer) environment for all of us (especially the little ones) until I move out of the house. Please remember my hope/plan is to buy them for the blower not the bag filters, etc.

Sorry for the long post! I know the above isn’t enough to design a ducted system or much else but hopefully you can point me in the right direction. As always, all advice is gratefully received!

Aidex

 

[Inspector]

My Clear Vue Cyclone comes with a 16 inch impeller on 5hp. Cyclones like ducts and hoses have a certain amount of resistance so the larger the motor and impeller the better. The 3hp you are looking into is a minimum if you want to capture the fine dust that is harmful to your lungs and your family. That will also capture all the larger chips. So the machine you are looking at is the right size but you can't take the motor and impeller off because the housing is incorporated into the section with the filters and bags. A DC with the motor and impeller separate from the filters and bags will let you play with how and where you mount it. There shouldn't be much difference in performance from impellers if they are the same size (13"/14" for a 3hp) and the inlets and outlets are not restricting the flow. A hose on the outlet rather than a large cross section square pipe for example. Newer impellers should be better than older ones primarily because they are larger but that doesn't always hold true.

The Bill Pentz's site has plans for building a very efficient cyclone, actually the design my Clear Vue is licensed from and is one of the most efficient. Many of the compact ones have more resistance and poorer separation performance.

http://billpentz.com/woodworking/cyclon ... nstruction

Pete

 

[Aidex]

Many thanks for your response Pete.

I’ll have a look at Bill Pentz’s plans for the cyclone. I wonder if the impeller size/power will dictate the dimensions of the cyclone or whether it’s a one size fits all approach?

Bill Pentz’s website is a great resource although there have been occasions when some things are a little over my head #-o

I’ll give more thought to the cheaper impellers and see if there’s any single phase 240V ones in the U.K. with more than 3HP motors.

Thanks again
Aidex

 

[Inspector]

If you can find a 3 phase 240 Volt delta wound machine you can get a variable frequency drive (VFD) to power it and that will also allow you to run it at 60 cycles like they do here and get extra airflow. It will also let you run it slower for the rare jobs like power carving with a Foredom where you want less suction. And lastly they can be programmed to start slowly which will draw less amperage if you don't have lots of power to spare. Start without tripping the breaker. The one I bought was about $225 to my door and it's for a 5hp motor.

 

[dzj]

Can you run a 3HP dust extractor and a 3HP machine (+ lights and such) simultaneously on the power supply to your shop?

 

[sunnybob]

you need to readjust your priorities a little. Sawdust destroys everybody's lungs, young and old.

Everytime you open that room door you flood the whole house with fine dust. It will be all over your clothes as you walk from room to room.
Spend more money on a good extraction system, now.

 

[kevinlightfoot]

Yes you can run two 3 horse machines and lights etc,I run a 4 hip. table saw and a 3 hp extractor simultaneously without any problems .They are both hard wired with 4 MM cable from my workshop consumer unit which is fed by a10 MM cable from my domestic supply .I only have single phase and my installation was checked by a qualified electrician,hope this helps.

 

[kevinlightfoot]

Sorry tried to edit but obviously didn't work hope you understood

 

[dzj]

Yes you can run two 3 horse machines and lights etc,I run a 4 hip. table saw and a 3 hp extractor simultaneously without any problems .They are both hard wired with 4 MM cable from my workshop consumer unit which is fed by a10 MM cable from my domestic supply .I only have single phase and my installation was checked by a qualified electrician,hope this helps.

It is, of course, possible, but the question is whether the OP has allotted a similar power supply to his shop.

 

[gmgmgm]

Aidex, you mention you're working in a "front room" at the moment, so you're going to be running on domestic levels of power. Probably a single circuit, 2x3kw in separate socket units at the very max.

I'd suggest keeping it simple for now would be easier. Your existing vacuum will work to an extent for a table saw (as it does for your TS75 saw), and means you don't have more kit cluttering the place. A chip extractor & cyclone only really comes into its own for planer/thicknessers.

I would get a air filter unit e.g. Record to clean the air in the room for an hour after you've finished.

 

[siggy_7]

Because I don’t know what additional tools I’ll buy in the future I thought to buy as big an impeller as possible in 240V. 3HP (2.2kW) seems to be the biggest single phase I’m finding but I don’t understand the different specs between manufacturers. Some have big differences in quoted volume of air movement, static Pressure, etc and none seem to quote air speed. Can I assume that at 3HP they’re all pretty similar in terms of performance (ignoring that some may have better quality motor, quieter motor etc)?

Some good questions here. For detailed answers, there is a sticky in the "Buying Advice/Tool Reviews" section, but essentially:

• Blower diameter and motor speed governs pressure. Pretty much any motor on this type of unit runs at 3,000rpm - so diameter is directly proportional to maximum (stall) pressure. Motor power in itself has nothing to do with suction pressure (this confuses lots of people!). However...
• Bigger diameter blower means more power needed per unit of air moved. More motor power means the capacity to handle a deeper (thicker) impeller, so more air flow moved. So flow rate is proportional to the motor power, assuming it's been specified correctly
• Most machines use about a 12" impeller. I am convinced that these are designed for the US market, which has 60Hz electrical supplies. Because we have 50Hz in the UK, induction motors spin slower. Therefore, to get equivalent suction, the impeller for a UK machine needs to be bigger. Unfortunately there don't seem to be any hobby grade machines that cater for this.
• If two extractors have the same size impeller and motor, then the performance won't be that different between them. What might be different is filtration (e.g. cartridge filter and quality) or build quality and longevity of motors.

 

[lurker]

I'm with sunny Bob on this. No matter how much I like my hobby there is no way I would use a dust generating tool in a dwelling. If you think you can capture and contain fine dust, you are on a fools errand.

Spend your money on a small shed or restrict your work to outdoors when the weather permits.

Sorry to be harsh but your kid's lungs are at stake here.

 

[Sideways]

Good detail in there Siggy.
I like the reminder about 50 vs 60Hz motors.
A machine with a US sized 12" impeller, if it had a three phase motor designed for 60Hz could be run off a VFD. The VFD would allow you to feed the motor at 60Hz, even though it's attached to a UK 50Hz 230v supply, delivering the higher speed / pressure / airflow that we want.

I have a different piece of kit with a Japanese motor rated at both 50 and 60Hz. Highest power out is at 60 Hz and it works perfectly with a VFD at the higher frequency. I'll watch out for this detail in future.

 

[Aidex]

Many thanks to all of you for taking the time to read my long post and for your help and advice!

I am conscious of the dangers and work outside when possible. For inside I use a portable HVLP extractor with flex ducting venting outside (leave it on for no less than 30-45 mins when I leave the room). I also have almost exclusively Festool tools which I always use with the Midi (who’s filters and bags I change/clean out regularly) with an Oneida Dust Deputy which I only open/empty outside far from the (closed house door). It’s also the reason I am yet to plug the table saw in, much less use it. It’s also the reason for my post.

I’m happy to spend more and was actually going to buy the Axminster industrial cyclone units but was advised by Axminster that either machine is overkill for my purposes and likely unnecessary. That’s what made me think of buying the biggest impeller I can find with a cyclone and venting the exhaust outside.

I assumed (perhaps incorrectly) that using the impeller with a cyclone and having the exhaust run outside (rather than any form of recirculation of the air with HEPA filters or otherwise would be the safest option (I don’t mind a cold room ).

I spoke with Axminster about an upgraded blade cover that apparently massively improves dust collection but I haven’t ruled making my own before I start to use the table saw if it proves a better means of collecting the dust at source.

Finally it’s also the reason why I am looking at machines that quote lots more air movement than that quoted as necessary for the saw. Basically a bigger is better approach (again possibly I’m mistaken here).

In any event many thanks to you all for all your help. Honestly it’s all taken on board. All our health is important especially the little ones’. Fortunately this is only a hobby (and one I seldom have time for especially of late) although there’s a few things my wife wants done which can’t wait until the outside shed/workshop is built.

In he meantime I’ll continue to research and ask and will take as much precaution as possible!

Many thanks to you all as always!!!
Aidex

 

[Inspector]

Aides you are on the right track with the bigger is better approach especially if you are willing to open up the ports on your machines to allow more air through them. In the case of your saw to also to make a larger dust cover for the blade. Any air your DC can pull over what you need for the saw can be taken through a bell mouth hooded duct near where you are working to capture the fines floating around.

Dumping the air outside is the best approach also as you won't have any leakage inside the shop through connections or filters leaks. I'm not so keen on the idea here as it can be -15C to -40C for a couple 3 months in the middle of winter.

One thing to keep in mind is the DC's sold for hobby use usually have greatly exaggerated airflow claims. They get the data by checking just the blower and no ducting or filters. It isn't a real world number and should be a third to half of what they claim. I would be interested to see links to the industrial ones Axminster didn't want to sell you to see if they are indeed too much.

On a forum in Australia one of the members with the lab grade tools measured vacuum cleaners for dust leakage and all leaked dust including the expensive ones unless they were in perfect condition. Some actually made it worse because the air went through the cooling loop of the motor and it chewed the dust into finer particles.

Pete

 

[Jamied]

Hi Aidex
Ive been reading your thread with great interest.
I am in a similiar situation as i also wish to duct outside with the biggest 240 volt fan and cyclone i can buy. I have obtained a large super dust deputy with a 6 inch port so i need a 3 HP extractor. Ive also been tempted by the cheaper manufacturers as i only want the fan not the bag filter or trolley but I also am concerned about the quality.
Likeyourself i have a festool extractor and dust deputy for power tools and i am very pleased.
Please let me know how you get on.
Jamie

 

[Aidex]

Hi Pete

Many thanks for your message. The machine I thought to buy at the outset is:
https://www.axminster.co.uk/axminster-i ... tor-210643

I was told
It would definitely work for my table saw and I suspect likely if I bought a small bandsaw and planet at some point in the future. It’s more that I was told it was a bit much for just my table saw.
They do a smaller one too which again the chap I spoke to reckoned was overkill for my purposes:
https://www.axminster.co.uk/axminster-i ... tor-210642

After they said this I thought why not buy or make a cyclone to collect the bigger debris and vent the exhaust outside so the fines are guaranteed to be outside my work area (house or workshop I fully intend to duct the exhaust outside) and pair this with the best/largest 240V single phase impeller I can find that’s suitable. And that’s what got me posting

With regards to the “bell mouth hooded duct” I’m not entirely sure what you mean...are you suggesting that it hangs above me pulling fine dust floating about up and out? If you have any pics that would be really helpful!

Ive heard that care should be taken when considering the figures quoted by different impeller/dust extractor manufacturers and that was one of the main reasons for my first post above. Unfortunately o have no idea how to know for certain which impeller is the “best” or if there is any way of distilling the numbers the manufacturers quote to compare a £1000 Axminster impeller with a £300 fox or Charnwood (all with same HP motors). Any advice on this is greatly appreciated!

 

[Aidex]

Hi Jamie

Will do! It’s really difficult. Generally one assumes that if something costs 2-3x more it’s “better” (even if it’s not 2-3 times better). However, given what an impeller with a motor is I wasn’t sure it was necessarily the case in this instance in respect of their air movement etc performance (i would expect the motor to perhaps last longer, bequieter, etc but given that it would have a couple of hours use a week at best that’s not my primary concern).