Thread: Under bench dust collector

https://www.timbecon.com.au/extracti...dust-extractor

I have a unit very similar to the Sherwood, same specs just probably a different badge. It is ok as a chip collector, but I dont think it gets much dust. It is also really, really noisy. Louder than the table saw. I dont use it much now, and definitely would never buy another.

Originally Posted by Baddabing

https://www.timbecon.com.au/extracti...dust-extractor

I have a unit very similar to the Sherwood, same specs just probably a different badge. It is ok as a chip collector, but I dont think it gets much dust. It is also really, really noisy. Louder than the table saw. I dont use it much now, and definitely would never buy another.

That answers that question.

Originally Posted by BobL

Dust extraction during turning is a variable feast and depends on who is turning it and and what is being turned.

This table may provided sobering information for all wood workers but more so for turners.
I have highlighted in red those that significantly exceed the nominal OHS dust levels of 5mg/m^3 for European softwoods
Attachment 451528
The data above is for professional turners. It does not take into account dust particle sizes/profiles, type of wood (some are more toxic than others - especially Aussie timbers) and the age and pre-existing health condition of the turners. If these are taken into consideration then all of the categories would have mean exposures above the recommended safety levels.

Until a newbie becomes skilled at both turning and sharpening, my testing shows that newbie turners make and scatter significantly more fine dust than pros. Newbies also use a lot more sandpaper than skilled turners. Like testing for dust from most wood working machines it's not much use performing simple spot dust measurements as the dust accumulates over time. The relevant danger levels of dust exposure depends on the age and health condition of the turner. The older and unhealthier the turner the less dust they can tolerate.

To illustrate this here are two direct experiences I have had in measuring turning dust.

At the mens shed there's only one turner that really knows what he is doing, the rest (fortunately not many) poke blunt or inappropriately shaped tools and lots of sand paper at rough looking bits of wood thereby generating lots of fine dust at all stages of turning. We don't have dust extraction on the lathes because they are rarely used (2 -3 times and we have excellent ventilation but it must be turned on. The ventilation is in the form of the many kW fan of the Evap AC unit that cools the shed. My measurements shows the AC fan takes about 10 seconds to clear the dust from the air around a lathe/turner (to that equivalent to outside air) that has been turning for for about 30 minutes. The area where the lathes are located is also large (~14 x 7 x 4.8 m) which is not the case for most DIY especially the OP who has a tiny shed which concentrates the dust to a greater degree.

In contrast to the above, at an annual WA turners convention there was a highly skilled turner demonstrating in a room with more than 100 people present and the demonstrator was using a large room air filter unit behind his lathe bench. I just happened to have a dust particle counter operating during his demonstration and the RAF not only managed to keep up with the small amount of dust he was making (everything was pre-roughed to shape) but the RAF was slowly during the demo making the room cleaner than it was to start with. The Demonstrator was stopping and talking often so not continually turning AND he did not use sandpaper for more than a few seconds every 10 or so minutes. The RAF in use was one of the bigger units (1000? cfm) running at half speed so maybe 500 CFM. I doubt many DIY turners would be at this level of skill.

Then it depends on things like what is being turned, a pen makes less dust than a bowl, hardwood makes less dust than softwood, dry makes more than wood with some moisture in it.Bill Pentz does not have any air flow figures on his website relating to lathes but my testing shows that even a skilled turner (not performing a demonstration where there may be as much talking as turning) needs at least 400 CFM for small stuff and more for larger stuff. A newbie or irregular turner will need more that this.

In practice the DC referred to by the OP will idraw less that 200 CFM when the thing is clean, and it's down hill from there. It does not need to be full as one session of sanding will create more than enough fine dust to clog sugar a small bag. One of these DCs I tested was less that 10% full but was so badly clogged with fine dust it was drawing

So, Bob, what you're saying is that I probably should have a vertical dual bag system, installed in a cabinet, vented to outside the shed, probably with some form of cyclone separator in advance. Whilst I'm getting that sorted I should focus in getting my sharpening spot on, my turning fast and efficient, roughing out green wood and only finish turning dried wood such that sanding is minimised? Oh, and wear a forced air face shield as well?

Does that sum it up to this point?

Cheers
Redbeard

Originally Posted by Redbeard

So, Bob, what you're saying is that I probably should have a vertical dual bag system, installed in a cabinet, vented to outside the shed, probably with some form of cyclone separator in advance. Whilst I'm getting that sorted I should focus in getting my sharpening spot on, my turning fast and efficient, roughing out green wood and only finish turning dried wood such that sanding is minimised? Oh, and wear a forced air face shield as well?

No cyclone unless, you get a something like a Clearvue.
Cyclones on small DCs are too restrictive to flow.
That's why Clearvue cyclones start with a 15" impeller and a 4HP motor.

If you don't have room for a DC, a 20 room change per hour ventilation fan would be better than the under bench DC unit you are looking at.

This style has always been very noisy, the drumming effect you get through the unit is horrendous