dust collection on the underside of a table saw.

[engineer one]

one of my tuits is to make a mobile stand for my dewalt 744 table saw.

i have the mdf 25mm, and will make a basic box with casters.
but i want to build in some dust collection at the bottom.
at the moment the design is "interesting" to say the least.

one one side of the blade below the table top, and underneath
is a plastic casting. the other side is open but kind of covered by
a metal plate which hangs down, and slots into the bottom of the
plastic. obviously it has to be loosish to allow you to undo and
change the blade. it does not however make for tight dust
collection. into the casting is also a dust collection tube which
exits out of the rear of the saw main plastic case.

so i want to cut off the dust extraction and then re-direct it
down wards to send the dust into a filter box under the saw.
i will then close off the slot at the rear and try for as much
dust security as i can.

i am thinking about a small hopper in the base of the cabinet
which can be readily emptied. probably need a small hepa type
filter, and some baffles to control the air flow, but should not be
too difficult.

anyone see a flaw in my logic? if i make zero clearance throat
plate, then no big bits should drop down.

then i can sort the top extraction with a tall pipe set up made
of plastic soil or other pipe.

so what have i missed??? :?

any other things to think about

paul :wink:

 

[Bean]

Look here I did this to my Kity https://www.ukworkshop.co.uk/forums...&postorder=asc&highlight=helping+kity+breathe

 

[engineer one]

thanks bean like it may well work something similar.

however i think i will be lazy and make the collector out of mdf,
with sloping sides.

my initial plan is to mount it to the underside of the table, and
make it big enough to allow the blade to retract to the bottom,
whilst allowing me easy access to the blade changing facility.

would gravity work, or do i need the extractor to actually be on? :twisted:

one thing tonight moving the saw about the amount of dust that has
come out seems to stop and start dropping out. where the hell did it come
from???? anyone would think i worked with wood :lol: :lol: :lol:

paul :wink:

 

[Bean]

You will need the extractor and i also think mine could do with a vibration cycle after shutdown, as it still collects some or more than I would like it to.

 

[woodbloke]

Bean - saw your earlier post and was sorely tempted to mod my K419 as you did yours, excellent saw but absolutely c#@p dust collection. Question for you is this - could you make the same type of collection hopper from some 12 or 15mm mdf, any particular problems you could see doing it this way? - Rob

 

[engineer one]

well i am so far building a small wooden collector around the bottom
of the blade.
starting out with ply, and where the blade moves through 45 degrees
tilt, i think i will add a kind of draft excluder brush to help keep it
more air tight.

underneath will be a big hole, and a collection bucket and plastic bag.
after all that i will see about power extraction because i am concerned
about airflow in 3 different directions, the blade, the top extractor,
and the lower extractor. any way lets see how stage 1 goes.

so i then come up with the next question which is blade type.

given the blades available it is often difficult to remember to change
it. and since i do a lot of sheet work, should i stick with the 80 tooth
one for cross and rip cutting since there is no grain problem?

but then for hard woods are there some guide lines to the different teeth
and forms you should use?? :?

paul :wink:

 

[Niki]

Hi Paul

I wish you good luck with your dust extraction and I'm following the post to see how it will come out.

About the blade selection I'm sure that more professional guys will come in, but, from my poor experience, the 80 tooth blade is very good for all the melamine and plywood sheets and for crosscut of solid wood (I'm working mainly with pine and oak), but for ripping solid wood, I noticed that its heavy on the 80 tooth blade and I had burning marks (too many teeth too much time at the same place and the blade is getting very hot), so I'm using 34 or 40 tooth blades.

Regards
niki