TS Dust Collection Help

[JackLeg]

OK, I've made the committment to install a proper DC system in my shop. One of my WW buddies is coming next Tuesday and we'll get started on the piping. (He has an efficient DC system in HIS shop) So now, I need your input on a couple of things. Got my metal blast gates already.

Yesterday, I spent the morning sawing "stickers" to use with the solar kiln. You know, those 3/4 X 1 1/2 slats you put between the layers of lumber. I ate sawdust off that PM for almost 2 hours.
Which put me to wondering, how do YOU keep all that dust that comes off the blade from covering YOU up?

Second, tell me one more time what type of plastic pipe you guys have used. I'm going 4". I think I saw gray S&D?

Thanks for your help.

[lwhughes149]

Reggie, some of your woodworking magazines will show an attachment to the top of the plastic guard. Your dust system comes overhead of the tablesaw and drops down to attach to the guard. Lorraine

[JackLeg]

I was afraid that was going to be the answer. I don't use the plastic guard most of the time. Was hoping there was some other workable solution.

Thanks for the input.

[Bas]

Originally Posted by JackLeg

Which put me to wondering, how do YOU keep all that dust that comes off the blade from covering YOU up?

Not very well. The blade on my tablesaw has a shroud around the blade that captures a lot of dust, but there is still quite a bit that's flung towards me when I'm cutting. I have a fairly small DC (Harbor Freight unit), but even with a 5HP machine I wouldn't be able to get all of it. I use Zero Clearance Inserts, so not much air will be drawn from above the table. Second, changing the direction of the dust being flung at a hundred miles an hour isn't easy.

An overhead guard is the only way to effectively capture the over-the-table dust. I don't have one, but I've seen a few. They work, but I don't like any of them If I can ever figure out a way to attach one to the ceiling, I'll build my own.

Originally Posted by JackLeg

Second, tell me one more time what type of plastic pipe you guys have used. I'm going 4". I think I saw gray S&D?

It's called Sewer & Drainage pipe, the thin wall variety. The product name is ASTM 2729. It's white, not grey (well, if it's clean). It's the pipe that costs $8 per 10ft. It's usually outside. Just go by price, if it's expensive, it's the wrong kind

Home Depot is having a sale on S&D fittings right now, saw the flyer this morning.

Oh, and get the non-perforated kind.

[JackLeg]

Thanks, Bas. Like you, every "over the top" intake I've seen either restricts your vision or is just cumbersome. I guess there's some things we just have to live with. I use zero clearance inserts also, but I wonder how much better, if any, it would be with a standard insert.

Thanks for the tip on HD fittings. My nearest one is 25 miles away, but, if the price is right, the drive will work. Thanks again man for all your help.

[Alan in Little Washington]

Reggie,

Dust flying off the top of the tablesaw blade has always bothered me, too. If you can wait a few weeks I'll have built and installed an over-blade dust pickup that is different than most of the typical commercial or homemade pickups.

As you know, the typical tablesaw over-blade dust pickup is a Plexiglass box /housing that is mounted to the ceiling or saw mounted arm via a set of parallelogram support arms with springs or counter weights so it can move up and down as the stock is pushed through the blade. When the box is raised the sides are away from the table and can allow dust to escape.

In the process of redoing some of my DC pipe for my autogates, I ran a 4" DC line to the ceiling over my tablesaw.

My over-blade dust pickup will consist of a section of pvc pipe that extends down to within 6" - 8" above the blade. The lower 12" will be able to fold up out of the way. A 4" X 8" horizontal Plexiglass plate will be mounted to the bottom of the DC pipe. Except when it is folded up out of the way, the plate will not move. A "grass skirt" will be attached to the perimeter of the the plate, extend down to the tablesaw top, and contain the dust until picked up by the DC air flow. I plan to make the "skirt" from trimmed truck/RV tire spray shield. The skirt will contain the dust, yet will easily flex out of the way, a few strands at a time, as stock is fed through the blade.

Note- this will be a "dust shroud," NOT a blade "guard"

[JackLeg]

Alan, friend, where have you been!! What you are proposing sounds like a sensible and workable solution. Can't wait to see what you come up with. I will put a drop over my saw and "stand fast." I'm in NO hurry to rush to yet another cumbersome "guard" assembly.

Thanks, man. You're the best.

[Alan in Little Washington]

Originally Posted by JackLeg

Alan, friend, where have you been!! What you are proposing sounds like a sensible and workable solution. Can't wait to see what you come up with. I will put a drop over my saw and "stand fast." I'm in NO hurry to rush to yet another cumbersome "guard" assembly.

Thanks, man. You're the best.

I can't promise anything since it is still a product of my mind and I haven't built a prototype yet. I will photo and post the results, but I need to finish the autogate installation first- hopefully that will be done in less than a week.

[JackLeg]

I've got lots more patience than money! Just let me know when you get to the "building" stage. I'm INTERESTED!

[Bas]

Originally Posted by Alan in Little Washington

My over-blade dust pickup will consist of a section of pvc pipe that extends down to within 6" - 8" above the blade. The lower 12" will be able to fold up out of the way. A 4" X 8" horizontal Plexiglass plate will be mounted to the bottom of the DC pipe. Except when it is folded up out of the way, the plate will not move. A "grass skirt" will be attached to the perimeter of the the plate, extend down to the tablesaw top, and contain the dust until picked up by the DC air flow. I plan to make the "skirt" from trimmed truck/RV tire spray shield. The skirt will contain the dust, yet will easily flex out of the way, a few strands at a time, as stock is fed through the blade.

Alan, I'm intrigued, in part by the grass skirt idea (is there any transparent/ semi-transparent material you could use for this?), but mainly by the "fold away" part. What I don't like about many of the commercial overarm guards is how to set them up and move them out of the way. I've looked into something like this:



but they're too short, I want something that's about 3ft long. But, your statement about folding it away implies a hinge/ pivot point - that would work! And it's much, much simpler.

Let's take this idea one step further (while we're still in the design phase). What if the grass skirt "strands" were electrostatic, to attract the dust? Dust clings to the strands, then travels upwards to the DC pipe via the air suction. We're not talking kV here, just enough to discourage the dust from escaping.

Another thought - we're always focused on trying to suck up the dust. What if the "shroud" instead contained a small tube that sprayed compressed air, to push the dust away from the operator? It's much easier to push than to pull. Yes, it ends up all over the floor, but that's why we have a ShopVac. At least you don't have dust getting into your face while cutting box joints for 4 drawers.

[Makinsawdust]

Originally Posted by Alan in Little Washington

Reggie,

Dust flying off the top of the tablesaw blade has always bothered me, too. If you can wait a few weeks I'll have built and installed an over-blade dust pickup that is different than most of the typical commercial or homemade pickups.

As you know, the typical tablesaw over-blade dust pickup is a Plexiglass box /housing that is mounted to the ceiling or saw mounted arm via a set of parallelogram support arms with springs or counter weights so it can move up and down as the stock is pushed through the blade. When the box is raised the sides are away from the table and can allow dust to escape.

In the process of redoing some of my DC pipe for my autogates, I ran a 4" DC line to the ceiling over my tablesaw.

My over-blade dust pickup will consist of a section of pvc pipe that extends down to within 6" - 8" above the blade. The lower 12" will be able to fold up out of the way. A 4" X 8" horizontal Plexiglass plate will be mounted to the bottom of the DC pipe. Except when it is folded up out of the way, the plate will not move. A "grass skirt" will be attached to the perimeter of the the plate, extend down to the tablesaw top, and contain the dust until picked up by the DC air flow. I plan to make the "skirt" from trimmed truck/RV tire spray shield. The skirt will contain the dust, yet will easily flex out of the way, a few strands at a time, as stock is fed through the blade.

Note- this will be "dust shroud," NOT a blade "guard"

Alan,
I look forward to seeing what you are making. A high percentage of what I do on the tablesaw can't be performed with a blade guard in place. The top side dust is a real pain.
One thing in your post jumped out at me. You keep referring to Plexiglass. Plexiglass shatters if it ever comes in contact with a spinning blade/cutter. Lexan (polycarbonate) gives the clarity but not the risk if it contacts a blade. I know it should not come into contact but unexpected things sometimes happens in the shop. Lexan cost more but is much safer for the application.
Rob

[JackLeg]

When that DC fires up, the static electricity will probably charge up the skirt?? What say you?

[TBone]

I currently use a shop vac with one of these
http://www.leestyron.com/sharkunisaw.php

He makes one with a 4" port also. It works pretty good.

[Alan in Little Washington]

Originally Posted by Bas

Alan, I'm intrigued, in part by the grass skirt idea (is there any transparent/ semi-transparent material you could use for this?)

I wish, but even clear strands would likely be impossible to see through because of their cylindrical shape and how they will likely refract/reflect light. Hopefully I will be able to see well enough through the Lexan top.

, but mainly by the "fold away" part. What I don't like about many of the commercial overarm guards is how to set them up and move them out of the way..... but they're too short, I want something that's about 3ft long. But, your statement about folding it away implies a hinge/ pivot point - that would work! And it's much, much simpler.

I plan to make a joint from two small collars, one possibly with gasket material on the face. Both will have one straight side on the front where a hinge will mount. I'll embed one or two rare earth magnets in the mating surfaces of the collars to "lock" lock the collars together. There will also be a micro-switch or magnetic proximity switch at the joint so that whenever the overblade dust pickup is folded up, the autogate for that section of DC duct is closed.

Let's take this idea one step further (while we're still in the design phase). What if the grass skirt "strands" were electrostatic, to attract the dust? Dust clings to the strands, then travels upwards to the DC pipe via the air suction. We're not talking kV here, just enough to discourage the dust from escaping.

I don't think that is needed. Most of the dust coming off the top of the blade is being "thrown" from the tips and gullets of the blade. The skirt will stop this motion. The DC air should flow under and through the skirt, draw the dust up into the duct.

Another thought - we're always focused on trying to suck up the dust. What if the "shroud" instead contained a small tube that sprayed compressed air, to push the dust away from the operator? It's much easier to push than to pull. Yes, it ends up all over the floor, but that's why we have a ShopVac. At least you don't have dust getting into your face while cutting box joints for 4 drawers.

Now you are getting a little too complicated- this would require an air line running down the duct. For the best dust collection for health reasons is collection at the source. So if possible, I want to get the dust at or very near the blade.

[Alan in Little Washington]

Originally Posted by JackLeg

When that DC fires up, the static electricity will probably charge up the skirt?? What say you?

I just need to test it, but I don't think so. The skirt material is pretty heavy stuff. It is made that way so it doesn't wear out quickly on the back of trucks. In fact, I wish I could find finer material- maybe go to a meat packing plant and see if I can get some horse or pig hair.