Sawmill question

[damato333]

I have a norwood mx 34. I just bought a dust collector from harbor freight. It is all hooked up so no more walking over a mountain of saw dust. The only electricity I have where the sawmill is, is a generator. Is it possible to run the dust collector off the sawmill? I know this is most likely not possible. But anyway I still would like to hear some opinions. The link for the dust collector is at the bottom.

http://t.harborfreight.com/2-hp-industrial-5-micron-dust-collector-97869.html

 

[BobL]

The only electricity I have where the sawmill is, is a generator. Is it possible to run the dust collector off the sawmill? I know this is most likely not possible. But anyway I still would like to hear some opinions.

Nope it will not run off the saw. The DC uses a 2HP motor and because of high start up currents (~40A at 120V) you will < 3kVA generator to start it.

It sounds like all you are worried about are the chips, if so then the DC filtration system just blocks air flow so I would ditch the bags and bag housing and just attach the impeller direct to a large bin, maybe on wheels.

I have done extensive testing on a range of wood dust extractors and in particular that dust extractor.
The claimed 1550 CFM is bollocks. This value is based on a single measurement in the middle of the flow of the naked impeller only. It does not take into account wall friction and (dust filter bags - which I would remove) and the 4" ducting so the flow rate is more like 550 cfm.
The grille in front of the impeller also robs about 15% of the air flow so the first thing to do would be to remove that
A significant greater flow can be obtained using 6" ducting but this requires throwing away the 4" adapter ports at the from and replacing this with 6" ducting like this.

All this will double the flow to ~ 1000 cfm
The impeller could also be flipped 180º to have the opening underneath.

FWIW When I modified the muffler on my 880 I noticed I no longer was walking over piles of sawdust. The muffler exits immediately below the point the sawdust does and this blows the sawdust way from the operator

 

[Sawyer Rob]

I think it will be real interesting to see what happens when a few bigger chunks of wood, get's run through it.

I've seen some bigger knots ect. come flying out of my mills outlet, and I've always worried about the fan on a HF collector breaking...

Please keep us posted...

SR

 

[damato333]

Nope it will not run off the saw. The DC uses a 2HP motor and because of high start up currents (~40A at 120V) you will < 3kVA generator to start it.

It sounds like all you are worried about are the chips, if so then the DC filtration system just blocks air flow so I would ditch the bags and bag housing and just attach the impeller direct to a large bin, maybe on wheels.

I have done extensive testing on a range of wood dust extractors and in particular that dust extractor.
The claimed 1550 CFM is bollocks. This value is based on a single measurement in the middle of the flow of the naked impeller only. It does not take into account wall friction and (dust filter bags - which I would remove) and the 4" ducting so the flow rate is more like 550 cfm.
The grille in front of the impeller also robs about 15% of the air flow so the first thing to do would be to remove that
A significant greater flow can be obtained using 6" ducting but this requires throwing away the 4" adapter ports at the from and replacing this with 6" ducting like this.
View attachment 402360
All this will double the flow to ~ 1000 cfm
The impeller could also be flipped 180º to have the opening underneath.

FWIW When I modified the muffler on my 880 I noticed I no longer was walking over piles of sawdust. The muffler exits immediately below the point the sawdust does and this blows the sawdust way from the operator

I figured it wouldn't work but I wish it did work.

 

[damato333]

I think it will be real interesting to see what happens when a few bigger chunks of wood, get's run through it.

I've seen some bigger knots ect. come flying out of my mills outlet, and I've always worried about the fan on a HF collector breaking...

Please keep us posted...

SR

After I got it all hooked up, I tested it just by taking handfuls of sawdust and throwing at the outlet on the sawmill. I was impressed at how well it sucked it up. My first worry after turning it on is exactly what you said. I could hear some chunks hitting the fan and everything is plastic on this so I can't imagine it lasting more then a couple years. I'll get pictures of the setup tomorrow.

 

[BobL]

I
I've seen some bigger knots ect. come flying out of my mills outlet, and I've always worried about the fan on a HF collector breaking...

Definitely a problem if the fan is plastic but the way to handle this would be to locate the impeller after the collection bin.
Of course the bin will need to be air tight and strong enough to support ~8" of Water column vacuum.

When I first started using my DC (Steel impeller) for turning I parted the unwanted end off a hardwood chisel handle nd they both got sucked into the open dust port. A second or so later there was a faint clunk and when I looked in the dust collection bag there was nothing but chips. There was not even a mark on the impeller.

 

[Dave Boyt]

The MX 34 throws out a pretty good spray of sawdust, and if the wind is just right (and it always seems to be), it blows right back in your eyes. My (Norwood HD36) dust collector is pretty primitive, but it works well, especially when I operate it as a portable mill (sometimes right in someone's front yard). I cut a section of an old tire to deflect the sawdust down, and mounted it on a bolt on the dust chute. It goes into a bucket that gets emptied every couple of passes. When I have it at home, the deflector puts the sawdust into a trough that I pick up & empty with a front end loader.

 

[Peterson Miller]

Nice one there Dave

 

[Mike Van]

Don't know if this will help, its what I did on my shop made mill over 20 years ago - Still working too - The blower I used came from Grainger, it's got about a 12" dia aluminum impeller, had some awful knots & chunks of bark through it over the years, never broken. Worst problem I have is hemlock when it's froze, it'll freeze inside on the housing, I have to thaw it [drop lite] and clean it every day then. The blower runs off the 10 hp 3 phase that runs the mill, extra groove in the sheave, it's not running 3450 rpm, maybe 3000, it clears the wet dust though. The head goes up & down,the blower has to too, so the 5" flex hose on top of the blower hooks it to the 20 ft long 5" plastic pipe on top, the 5" pipe slides in & out of a 20 ft 6 inch. You can see the action where it goes out the end of the barn,

 

[hamish]

I think it will be real interesting to see what happens when a few bigger chunks of wood, get's run through it.

I've seen some bigger knots ect. come flying out of my mills outlet, and I've always worried about the fan on a HF collector breaking...

Please keep us posted...

SR

The do break, and make a real eerie noise as you try to shut things down. I am trying to figure out how to add a cyclone in line that will only remove the heavier pieces, but no luck as yet.

 

[BobL]

The do break, and make a real eerie noise as you try to shut things down. I am trying to figure out how to add a cyclone in line that will only remove the heavier pieces, but no luck as yet.

A standard cyclone connection will be fine.


I've seen a large tape measure sucked up by such a setup and apart from a couple of scratches it was fine.
Make sure you use 6" ducting as it can carry 3 times the air of a 4" duct

 

[hamish]

A standard cyclone connection will be fine.
View attachment 402808

I've seen a large tape measure sucked up by such a setup and apart from a couple of scratches it was fine.
Make sure you use 6" ducting as it can carry 3 times the air of a 4" duct

I exhaust my sawdust outside of the barn into a pile, and would prefer it outdoors in a pile versus containing it in a bin.

 

[BobL]

I exhaust my sawdust outside of the barn into a pile, and would prefer it outdoors in a pile versus containing it in a bin.

Then you have no choice but to pass the sawdust through the impeller.
The way I would do this is use an industrial strength impeller made using around 5/32" thick steel plate

 

[damato333]

The MX 34 throws out a pretty good spray of sawdust, and if the wind is just right (and it always seems to be), it blows right back in your eyes. My (Norwood HD36) dust collector is pretty primitive, but it works well, especially when I operate it as a portable mill (sometimes right in someone's front yard). I cut a section of an old tire to deflect the sawdust down, and mounted it on a bolt on the dust chute. It goes into a bucket that gets emptied every couple of passes. When I have it at home, the deflector puts the sawdust into a trough that I pick up & empty with a front end loader.

I like your idea. I should've done that. It seems like I always choose the most expensive and difficult way to do things.