[UnleveledDesigns]

So I dug through the old forum posts looking for a strategy that was successful in dust collection on a table saw and i saw this thread where Marvs setup seemed to be the way to go.. however the images aren't appearing so I'm asking anew.
My situation:
I have one of the current model Dewalt saws that originally comes with a wheeled base that i have moved onto a mobile work bench to one side of my garage.
I have a 4 inch dust collection line that runs down the center of my shop with a drop hose i used to connect to the dust shoot on the saw. This gets the majority of the dust but i feel it could be better. My thoughts are to add a Y to where my elbow currently comes down and extend the 4 inch line to directly above the table saw. From that point come straight down but that is where i get stuck.
1) What is the best way to make the dust cover,
2) what is a safe distance to come down with solid pipe and convert to flex hose
3) ideas to make it where i can move the whole thing out of the way since this work bench is my primary.

For now we will ignore that i should move my dust collector closer to my primary tools as i already know my setup is less than ideal in that regard.

Thanks for the assist.

 

[Steve Neul]

I think I would have gone into the saw on the right side with the hose. Where it is now looks very much in the way.

You can't really expect the same level of dust collection with a contractor saw. It isn't sealed as tight as a cabinet saw. Anyway just build a box to set the saw on that bottom of the box is on a angle toward where your hose is connected. Air flow and gravity will get the job done.

 

[woodnthings]

dust collection is an art and a science ......

To truly get into the art and science of dust collection you need to do some more research than simply looking at what others have done. I suggest you read at least the Part One Chip Collection and Part two Fine Dust Collection in the is Basic Course by Bill Pentz, a leading expert on the subject:
http://billpentz.com/woodworking/cyclone/beginnnerscorner.cfm

Blower speeds and CFMs by most home DC units are inadequate as are the housing and cabinets that manufactures provide with their table saws. The newer job site saws and table saws have a blade shroud that encloses the blade with a shop vac port at the rear. This works extremely well, as I have a Bosch 4000-09 with that exact configuration. You must collect the saw dust traving at 100 MPH or so right at it source to be effective. I made a sheet metal shroud for my 12" Powermatic 12" table saw and connect it to a 4" port I soldered on the shroud. That also works way better than "gravity and a sloped" panel in the cabinet of the saw.

Contractor saws are tough to deal with because there are so many openings which need to be sealed off :frown2: But you don't want a completely sealed box because you need the air to flow in and out and to for the dust to stay "airborne" to be effective. Gravity will settle out the dust and chips IF there is not sufficient CFMs, at least 600 CFM, my recommended minimum number, and ideally 1000 CFM! :surprise2:

An excerpt from the above mention source:
Blower technology is mature meaning professional commercial blowers of the same size, type, and speed move very close to the same air regardless of which major name blower we buy. Unfortunately, lots of testing shows other than Jet and Delta, most small shop blowers are not well made so move much less air. This means the commercial blower tables show the maximum we can get, not what we will really get. How much air our blower moves depends upon how much resistance we have in our system. This resistance is known as static pressure. Static pressure includes the airflow losses with our tool hoods, losses from duct and flex hose friction, overhead to run our system and the overhead to push air through our filters. It takes a lot of extra work to force air in the tight separation spirals inside our cyclones, so that overhead requires a bigger more powerful blower. The commercial blower tables show at normal static pressure resistance levels it takes a 3 hp dust collector or 4.2 hp cyclone to move our needed 1000 CFM assuming a clean filter and amply sized ducts. Because 4.2 hp motors are not readily available, most need 5 hp motors to power their cyclones.

See the CFM Exhaust Requirements in this chart in section H:
http://billpentz.com/woodworking/cyclone/dc_basics.cfm#BlowerFanTable

I found that an over the blade dust collection shroud works real well when hooked to my shop vac. in conjunction with a 4" port under the saw cabinet allowing gravity to work somewhat effectively BUT it does not evacuate the all the dust from the cabinet where it settles in the corners.

To see more of what I do look here:
http://www.woodworkingtalk.com/f7/dust-collection-woodnthings-shop-part-1-a-20273/

 

[UnleveledDesigns]

replies

I think I would have gone into the saw on the right side with the hose. Where it is now looks very much in the way.

You can't really expect the same level of dust collection with a contractor saw. It isn't sealed as tight as a cabinet saw. Anyway just build a box to set the saw on that bottom of the box is on a angle toward where your hose is connected. Air flow and gravity will get the job done.

The collection actually works quite well as the blade has a shroud around it as woodnthings mentioned. Occasionally the hose gets in the way but not as often as you might think as i normally cut my large sheet goods with my skill saw since the bed isn't big enough for me to properly control them. The main reason to be on the left is that i also use the hose to vacuum out my car and I use the chop saw much more frequently so didnt want the hose dangling right in the way all the time.

Woodnthings:
Thanks for the input, I actually did about a month of research before setting up the dust collection and deciding between shop vacs and whatever else. I sized the dust collector using a bit different table and considering 13" planer as my most dust producing source needed this led me to my blower rated at 537CFM:
http://images.woodmagazine.mdpcdn.c...1500_1500/public/image/2016/11/03/Table 1.jpg
Again, I know well that i could move the blower closer to the saws I most use and drastically increase the efficiency however i prioritized tools in the locations i preferred and put the blower out of the way.

I've not considered using shop vac to connect over head but even if i take that route the part that gets me a bit messed up still is how to build something that can support the hose but also move out of the way easily. Would Love if i could fit a nice big boom like normal folks would do but I just don't have the space unless I move the car outside full time, hence the reason trying to come down from the ceiling.
Just need some ideas on the way to make it move up and down easily but also to stay in place above the saw when i set it there. The shroud itself I figure I will buy or build one but the mounting mechanics are where ideas would be useful.

I will take a look through that article you've sent as I'm always looking to learn a bit more.. And also to set up research for what shop filter i'll be buying hopefully soon to clean up the air a bit more.

 

[ducbsa]

This may have some useful info: http://www.woodworkingtalk.com/f2/table-saw-throws-saw-dust-me-84921/

One of these may be useful: http://www.rockler.com/table-saw-and-jointer-hoods-table-saw-hoods

 

[UnleveledDesigns]

Ducbsa, I'm not sure if the item from rockler will do the trick or not, from what i have read it needs to be a bit more concentrated over the blade.
Woodnthings solution from the post you linked is almost what i am going for but again, I need ideas on what to use to come from the ceiling not from the side.