Thread: Dust Extraction for Lathes

Jeferson mate the start of your problem is your asumptions.....you are obvioulsy not venting the entire area as it stands.

You need to be addreesing your dust collection as a priority..do that properly and you will not have anywhere near as much heat loss as you may think

the second stage of your problem is lay out.

If ya not prepared to lay out your workshop in a way that is advantageous for dust extraction...well its going to cost you plenty.

As far as being worried about the"foot print"...oh come on mate ...I've looked at ya pictures and you have plenty of room.

Move the lathes closer together and in a way that makes the dusct lengths shorter......no matter what extractor you use..that lay out will cost you in both $$$$ and air flow.

Ya just dont seem prepared to do what it takes to get a result.

cheers

Hey Jeff

I can see your problem. Look really closely at your photos.
It's that bloke!
You should never have let him in your shed.

Ok jefferson...real solutions.

lets talk baby steps.....take that big gulp hood and put it to good use else where.....filling pot plants perhaps, or put it on ya head to keep the sun off......take the stand that you have it on and fit it with a couple of feet of 100mm PVC pipe.....if ya worried about it getting donged or you donging it, fit a standard 100mm rubber expansion fitting to the end.

You can fit PVC pipe to dust hose by using standard joiners cut in half as adaptors, glued in.

Take that 2Hp jet dusty you have sitting way out over there, in the middle of the floor. move it right up to the left of the head stock and cut the hose as short as you can manage...2 meters tops...if you don't do tail stock drilling on that lathe you may be able to get away with 1 meter.

If you braught another lathe in headstock to head stock on the other side of the dusty, it will serve two lathes no problem

Now move the end of that pipe right up next to the work...like 4 to 6 inches away... no more....... from where you are cutting or sanding.....closer if you are game.

And all this should cost you....$50 tops and about an hour.

don't bother me till you have tried that.

cheers

Soundman,

I take your point about the layout. Originally this end of the shed was for woodworking.

Then I bought a lathe, had some lessons from and others and I got the bug. Big time. I couldn't tell you when I last made some furniture. (Kitchens yes but that's another story.)

I've had the lathes in different positions before. But I'm pretty happy with where they now sit. One on the west wall, one on the east and one in the middle. Most of the cupboards that you really can't see in the pics I intend to move. And, if I decide that way, will probably invest in a cyclone and metal ducting. I reckon it will cost me plenty. $ are not the issue. The issue is what will work best. Mobile DCs are APITA.

I spend most of my time on the VL 175 which sits under a window. With the swampy on high, most of the dust goes straight out the window. The problem child is the VL 300 which has no window and the A/C misses that corner of the shed. Winter also is a problem when I have the fire going.

And I don't have as much room as you think. I've got two wet stone grinders, two spark grinders, a bench and two mini lathes to store here.

I've spent hours reading a lot of the threads here and the Bill Penzt stuff takes some ingesting. I do appreciate your views, I just don't happen to agree with you in the main. But I would like to keep matters a little more civil.

Obvioulsy you are not happy with the positions of the lathes because you cant get good dust extraction to them.

As far as space...hell most of us would fit all five lathes, 3 dust extractors, a couple of band saws, sanders and two trailer loads of wood a partrigde and a pear tree in convienient pieces AND have friends over for smoko.

Y not getting the best value or effectivness out of the gear you have...so dont waste you money till you d better with what you have......because you wont have learned the lessons and you will be disapointed because you wont get the results from whatever you buy.

How ya going with that piece of pipe to replace the big gulp.?

cheers

Originally Posted by jefferson

Thanks for that John.

I've got no idea what airflow I would need. All I know is that I need to vent the entire area on a regular basis. That will cost me a lot in firewood over winter. I need the most flow at the Stubby, as I won't get a hood close enough to the work. Sorting out the ducting alone will be a challenge, let alone the hoods and how to move them.

The other option you have with a system like a Max is to have one 6 inch port servicing the lathe and another open (perhaps overhead) to recirculate air in the shed and to scavenge any stray dust, especially around the operator. Have a look at your layout and ask yourself where you would like the air to flow and set up the second port accordingly.

I have no idea of the cost of steel ducting. May I ask why you are thinking down that line rather than (say) 225 mm and 160 mm PVC? Just curious. PVC is so easy to cut and fit into place.

I'd be surprised if one 6 inch pipe (close to the work, as Soundman says) and another to draw clean air over and past the operator would not do a pretty good job. I am putting together a flexible arm so I can pull a bell-mouth PVC inlet attached to a short lump of flexy very close to the work. I have a Big Gulp right now, but Bob and others have advised me that I'll get a better shaped negative air bubble (extending further from the end of the inlet) by using a bell-mouth. Thankfully, thermoforming a PVC fitting or pipe section is quick and easy.

Cheerio!

John

Seriuosly there is no need for the second inlet.

The primary suction...maximised.....right at the job.....where the dust is comming from.....will be pulling air out of the room.

A second open port just somewhere in the room will do bugger all....because it is non specific pulls cleaner air as well as dustier air.


It is important to understand that we need to be getting as much of the dust as close to the job as possible......the more dust that is captured close to the job, the less will be else where.

where is there more dust.....close to the job.....the more you suck close to the job the more dust you will remove from the room.

Good suction close to the cutting will also create an air flow away from the operator.

If you got spare suction and spare port.....bring that in close to the work as well..maybe from a different direction or where the other port misses some.

cheers

Originally Posted by soundman

Obvioulsy you are not happy with the positions of the lathes because you cant get good dust extraction to them.

As far as space...hell most of us would fit all five lathes, 3 dust extractors, a couple of band saws, sanders and two trailer loads of wood a partrigde and a pear tree in convienient pieces AND have friends over for smoko.

Y not getting the best value or effectivness out of the gear you have...so dont waste you money till you d better with what you have......because you wont have learned the lessons and you will be disapointed because you wont get the results from whatever you buy.

How ya going with that piece of pipe to replace the big gulp.?

cheers

This quoting stuff is pretty good!

Now Sandman, it is a given that I will not be moving the lathes again. The question is what is the best way to get dust extraction to 3 different lathes, all of which have different needs. I say again, the LB VL300 has two banjos and a 600mm rest. I turn rolling pins on this lathe and need (I think) a rectangular gulp chute that long. The VL 175 has it's own problems when I use the swivel head. All the dust comes out the front. Saves my back though. As for the Stubby, well stuff just sprays everywhere. Another given is that I don't want pipe all over the floor from three different DCs. Thus the crappy 3/4 HP units hanging from the walls at two lathes.

Room? I want more, not less. I should have made the turning end another bay wider. I spend most of my day, every day, in that 9m x 6.5m area and it's crowded. It's my space and comparatively small when my shed is 25m x 9m.

And the reason why I keep asking the questions is so that I get it right this time. I know it's wrong now but I want a solution. I think it's a ClearVue Max.

And no, I've done nothing about the gulp chute yet. I see that as part of the makeover.

Originally Posted by John Samuel

The other option you have with a system like a Max is to have one 6 inch port servicing the lathe and another open (perhaps overhead) to recirculate air in the shed and to scavenge any stray dust, especially around the operator. Have a look at your layout and ask yourself where you would like the air to flow and set up the second port accordingly.

I have no idea of the cost of steel ducting. May I ask why you are thinking down that line rather than (say) 225 mm and 160 mm PVC? Just curious. PVC is so easy to cut and fit into place.

I'd be surprised if one 6 inch pipe (close to the work, as Soundman says) and another to draw clean air over and past the operator would not do a pretty good job. I am putting together a flexible arm so I can pull a bell-mouth PVC inlet attached to a short lump of flexy very close to the work. I have a Big Gulp right now, but Bob and others have advised me that I'll get a better shaped negative air bubble (extending further from the end of the inlet) by using a bell-mouth. Thankfully, thermoforming a PVC fitting or pipe section is quick and easy.

Cheerio!

John

John, the fittings for 225mm PVC are steep. And I've got onto a supplier in Melbourne and the prices for steel pipe and fittings seem reasonable. This is a one-time investment. (I also have the woodworking end of the shed to plumb.)

I look forward to seeing how you get an adjustable arm with the right hood. Keep me posted.

I'm still waiting for Bob L's feedback and suggestions about the venting question. I'll annoy him via a PM if he doesn't come on line soon.

I got an email saying that the turner in the pics was the problem. I think one of the Mods deleted it. But whoever it was had it right. Col, my friend, is the 11th best turner in the local club. He has no idea how to do a push cut or how to finish with a scraper. He goes too thin and can never get an even wall thickness That's Col. He's a big unit.

Originally Posted by jefferson

I'm still waiting for Bob L's feedback and suggestions about the venting question. I'll annoy him via a PM if he doesn't come on line soon.

Suggest you ask Bob about whether a single 8 inch port close to the job or two 6 inch ports is likely to be superior.

All my work has been to optimise capture at source, so I am tempted to go with a single 8 inch port, but I have never tried to collect dust from a lathe.

Cheerio!

John

Yet again the big end of town has got carried away pushing this 8 inch ducting.......there are real issues and practicalities.

6 inch ducting will work...very well....particularly if you keep the lengths and the fittings to a minimum.....6 inch PVC pipe and fittings is not that expensive.......4 inch ..hell its cheap as chips.....if you are frugal with ya lengths 4 inch duct will work..and well.

So ya don't want to do the easy thing and move ya lathes.......better dig deep chum.

As for replacing that big gulp hood.......less than $50 and an hours work and ya not interested in doing it so you can learn something.

as for the requirements of all the lathes.....they are the same....air flow close to the job.....lots of it and very close.

As soon as you introduce any sort of thing that looks like a funnel, your air flow plumets......ya cant avoid it.

Two round 4 or 6 inch inlets.....with bell mouths.....if you like...... is about as good as it is going to get..put a rectangular funnel looking thing on the end......you have just taken a step backward.

Stop fiddling and arguing...put that piece of 100mm pipe on that stand in place of the useless gulp hood and you will have some idea...do it tomorrow.

even those pissy 1hp single baggers will do better if you get the hose close enough to the work, instead of nailed to the wall.
Just get a piece of #8 wire and make up a hook so you can hang the hose on the bed of ya lathe right next to the work...hell how long will that take...5 minutes.

come on mate you have to help ya self.

cheers

Soundman, don't call me a chum of yours. I'm not. I take some objection to that.

You say that 4 inch pipe works well when all the experts disagree with you.

I can safely say that 4 inch flexi isn't taking the dust out of my Sawstop. Poor design, yes. Bigger port required, yes. But not to 4 inch pipe.

What is it about you?

Is a cyclone beyond your reach or just your sensibilities?

I've asked several times for the IDEAL solution and all you are giving is bad advice. Everyone says to open the ports on your machines. All you keep saying is to use short 4 inch flexi and a dust gasping 3hp DC. Again, show me what kind of turning you do and how you solve the dust problem.

You've lost me.

This stuff goes world-wide and some poor bugger will think you're an expert.

Jefferson,

Every expert opinion I have read says we need a minimum of 6 inch duct, with airflow of at least 1,000 CFM, and velocity of about 4,000 FPM to get effective dust control. This mirrors my own experience. Once these numbers were hit, my dust control improved by several orders of magnitude. There are, of course, other requirements. For many machines (lathes are one example) we need to keep the inlet close to the work. Hood/shroud design is also important.

I can advise you on spindle moulders, drop saws, table saws, drum sanders and linishers, but I have no experience with lathes. But we do know lathes are dirty machines; it is a tough situation for dust control.

We also know a 4 inch line maxes out at about 400 CFM, my guess is less through a flexy ... nowhere near enough air if our aim is to the collection of fine dust. Even if being pulled by a 5 HP motor, the CFM and velocity through a 4 inch line is terrible. I know this from bitter experience. An enormous impeller driven by a monster motor won't pull enough air through a 4 inch line. A six inch line (with a good impeller and enough HP) can give you 1,000 - 1250 CFM. An eight inch line connected to a CV Max (or similar) running at 60 Hz is going to do a lot better. You have made it clear you are concerned with fine dust control, so my guess is that the minimum you could use is a CV Max, probably with a VFD running at 60 Hz. The VFD lifts your airflow by about 20% (compared with the same impeller being driven at 50 Hz).

The magic numbers are no accident. They are physics. If you want a bunch of air you need three things: a duct big enough to carry the air; an impeller and motor that will pull the required CFM and keep them at or above 4,000 FPM, and ports/shrouds that put the airflow where it is needed.

One of the first principles of effective dust control is to optimise capture at source. It is for this reason I departed from accepted practice for my spindle moulder. Accepted practice (see Bill Pentz's web site) is for a 5 inch line to the side of the cabinet and a 3.5 inch line to the fence (or similar). I opted for a 6 inch line to the fence, and nothing to the cabinet. The effect of this big airflow across the cutter is to draw air up from the cabinet through the opening in which the cutter sits. Because I have such a heap of air being pulled over the table both chip and fine dust collection is excellent. I am willing to listen to other options, but right now am a happy chappie.

Soundman and I do agree on one thing, the Big Gulp is not a good solution. I made that mistake on one of my machines, but I was looking for a fast, quick and cheap interim solution. A bell mouth will give your negative air bubble a longer (towards the work) profile. BobL has done a bunch of work on this. A bell mouth is the way to go. Because you can quickly make up a form on a lathe, thermoforming a bell mouth will be quick and simple for you. If you have never done thermoforming before, don't sweat it ... it is a piece of cake.

I am no expert at dust control on lathes ... but the experience with several machines is that a large airflow with the inlet close to the work is often, if not usually, a good solution. Everything I have read indicates that this situation exists for lathes. Have you considered joining the CV forum and finding out if anyone there has hooked up a CV Max to a lathe? You might get some good info there. Also, why not write to The CV people about your situation. If you tell them The length of the duct, the number and type of fittings etc, they should be able to tell you about how much air a CV Max will pull through a bell mouth ... with and without a VFD.

Jefferson, this decision making phase is the hard part ... but don't short cut it. Once you are happy with machine and duct selection etc, it gets easier. This is not a new problem. Someone, somewhere is doing great fine dust control on lathes. If you can find a couple, their guidance will be far better than mine.

Cheerio!

John

Well chuckle chum, I did the whole cyclone thing something like 10 years ago...that was when we all built our own....I still have a small one that works very well...its still 5 times bigger than a good modern shop vac.

Um yeh....had most of these discussions before....seen things work...and not

We had cyclone devotees then too.....we had our share of engineers too...yeh several of those playing with or thinking about cyclones at the time where engineers.....Sturdee probably remembers (I cant recall did Sturdee build a cyclone)....but the fact is cyclones have their draw backs....the two biggest are that they are wastefull on air flow and suction, the second is that they are unavoidably large and inconvienient.

A third is that if you have insufficient or disturbed air flow their seperation efficiency plumets from above 99% to well below 50% if you slow the air down enough...and then you get lots of dust comming out of them.
This is why all the professionally built modern cyclone systems have output filters.....lots of the current crowd are not running any output filters.

As for the whole big duct thing...yeh....that is nothing new...we had blokes running 6 inch duct arroud then too.

So you have coughed up for this cyclone thing....had to buy a blower bigger than a conventonal system needs and had to duct it because the cyclone is too big and combersom to wheel round....AND ya not going to buy 2 cyclones so ya ducts have to run a long way across the workshop.

Of course if you have lost a fair whack of static pressure (suction), thru the cyclone and you have had to run long ducts.....well ya gona need big pipe just to compete with a simple mobile dust extractor running short ducts and close by
AND by the time you baught the cyclone...the output filters and installed it and all the ducting..you could have baught 2 decent mobile dust extractors.

as far as ya saw bench and the corigated duct...yeh buddy..been there.....the corigated duct is lossy as hell..and I bet you got about 2 meters of it between ya dust extractor and ya saw bench.....yeh been there too.

Put ya dust extractor right next to the saw bench and get some straight 100mm pipe, less than a meter long..using the same dust extractor and things will be different.
Oh have you worked over the saw bench and modified it for best dust capture.

As far as the ideal solution......it does not exist.

As I have posted elsewhere, this dust extraction part of the forum seems to be dominated by those who are chasing magic numbers and are prepared to spend a lot of time and money fiddling to achieve them.

As I say, some of us have been round long enough to have seen it before, had the discussion before and know that there are reasonable and economical solutions, that do work.

the physics and the maths remains the same, the difference is the better off the shelf dust extractors are more effective, flow more air and are cheaper than they where 10 years ago....making cyclones even less attractive.

Bad advice.....dont think so...an alternative view that represents what most people can achieve and afford.

cheers buddy