J. Phil Thien's Projects

Is a 16 inch diameter drum too small?

its tight but will  work. larger the better

I think I would like to make an 8" tall top hat, with the inlet located towards the top as people have suggested the taller top deals with fine dust better.. Or, should I make it 6 inches tall and center the inlet?

i would go 8 minimum. it give more time for the dust to move out to the side and ready to seperate out

How long should the transition from the 4" inlet to the rectangular opening be?

not sure but the longer the better. the more gentle the transition the better. remember to add 10% area to allow for the transition

How far into the top hat should the outlet extend? I've read half the distance, but half of what distance, the top hat or the inlet?

the way i do it is half the inlet size up from the baffel plate.

Does it matter whether the inlet is on the right side or the left side?


in theory yes but practically no. if the dust is spinning the same direction as the impeller the motor  should have less work to do and can move more air.   an air straightener will make it even better  build it whichever way suites your workshop

very nice. looks good. report back how its working

definetly better than normal pipe . probably could do with being bent to a more flat shape (90 degrees to the side) on the bottom

im not sure would you gain anything by using a 45 degree fitting. the dust still has to change direction 90 degrees. might be a small help but not a lot.

moving to a side inlet or top hat would really help

the purpose of the solid part of the slot is to break up the airflow above and below  the baffle. if the was a slot all th way round the air below would increase in speed and keep blowing the dust back into the air where it could be sucked up the outlet,

something i meant to try was having a second baffle   and see would that reduce air flow more

no never got around to it

if i was doing this myself (which i havnt)
i would go a fairly large diameter
double or triple height.
narrow slot . its only fine dust
i would put a section below the baffle to keep the seperator well away from the settled dust


but the most important thing to do first is to catch as much dust as possible before it ends up in this system.

could you use some kind of low density board to close off the vac table but still be able to get suction through it

i dont see any issues extraction wise . condensation and damp could be a problem . if i was doing it i would box off the pipe outside and insulate around it.

is this running through the normal dc system or a high pressure system

i think i would put the sloped part below the baffel plate. it might cause problems above it

sorry for not getting back. i forgot.

the inlet should be recangular with a transition to round. preferably 10% larger area than area of pipe.

the outlet has to be concentric to the seperater

retired2 is correct. go up a size. it should have a slightly less resistance than the normal sized pipe

the baffle plate is designed to seperate the top chambe from the dust collection bin at the bottom. the smaller the slot the less will go down but the slower the air will be below the bafffle. you want fast air above and slow air below

not sure what your second idea is. are you trying to force the air down into the slot,. ths would have a very bad effect on efficience . it would drive all the dust in the bin all over the place and allow it to get sucked back up

im not 100% sure what your asking but i think your asking if you can put the seperater part inside the ring of the dust colector
yes you can
personnaly i wouldnt . its too restrictive measurments wise. it could be done , and i think iv seen it done on here .

no harm in trying

its a tricky one.
it would be interesting to find out.