J. Phil Thien's Projects

have you a pic

if you have  a seperater on each line of the ducting that are parralel to each other then it should b fine. but put them in series and you will lose .
not sure its worth doing parralel but if it makes sense in the space then go for it

adding  seperater will reduce airflow  and pressure  by a suprising amount. . adding in 2 will cripple the system unless you have crazy air flow before. unless you are using the chop saw continuesly  it will take weeks or months to fill the drum  but you will fill is from the planer in less than an hour. you wont notice the chop saw dust  in the drum compared to the planer.
i would do one goo seperater  rather than 2

i think that width is a sweet spot for general use. too narrow and shavings will catch , too wide and you allow more air to spin in the barrel bellow . if i was building a dedicated seperator just for shavings i would widen out a bit  and if it was just for fine sanding dust i would narrow it a bit.
i dont think enough testing was done to really see the data on it. i wish i had a month spare with nothig else to do only try out all thee variables to see what happenes.

as for the 240 degrees. the same aplies, just a sweet spot. if the slot was longer then more air will spin below the baffle and create problems. too short and not enough dust will drop down

this si what is recommended  here most of the time. a super thin baffle would be great. if i ever rebuild mine i will probably use a 2mm steel sheet for mine with a smaller ply piece under it for support.
i chambered mine  down from 18mm to maybe 4-6mm maybe at a roughly 30 degree angle.
it works fine.

someone posted a link to a study on this last year (or earlier) . it claimed that having the air enter the impeller straight with no rotation was better than rotating the same as the impeller.

I don't have an air straightener but it is on my list to add the next time the separator is disassembled.
retired 2 has  one I think. check out his thread for his data on it.

ultimately I think its one of those things that has very little benefits that its not worth ripping things apart to change but well worth doing if your building or changing anyway.
as a result I would choose the rotation direction based on what suits

I don't have much experience with plastic drums  and none with push seperators.

what do you mean by pressure. is the barrel expanding. I don't think it should. it is a very open system and should  allow the pressure out the top  rather than down into the barrel.

that's an unusual set up. is the outlet flush witht he top of the cart and the planer sitting on top. is there enough room for the air to escape.
I would try raising the planer a fit first then  try it again.

your inlet looks like it is going into the top of the rectangular inlet.


you have nothing to lose by widening the outlet. it should help but it would be a fine line  between perfection and allowing bypass.
have you a pipe in the middle  upder the outlet

yours is a single height system so  half way  is best

what I was suggesting is that if you have 2 holes  the first say 20mm  and the second 35mm  . your slot will be wider at one end . generally on a normal slot that's good but it would only be the last few inches where it widens out. . I would like to see it tested. I don't know how it would work in reality. there is a lot of variables .
the down side  as retired 2 says is that if you try what im imagining then its harder to go back  to a full narrow slot because its wider  in places. . given that you are using a common lid it wouldn't be the end of the world to get another lid.

that should work. but as retired 2 says it will be very prone to catching shavings. I would make the hole at the end of each slot  larger so that the slot is tear drop shaped. that will help  with the clogging issue.

I would add a piece of pipe in the centre  as the outlet to move the point  where the air moves into the outlet down away from the top of the separator

that's very sad.
ultimately all our collections will go the same way


for some reason I thought you dc  was in 2 parts like the OP is talking about.

you say you have practically no dust in the bag  . do you think you could do away with that bag  and build something else instead..
I wonder could you make a bucket  with a pipe in the centre that passed through . then attach the filter to the top  and the dust collector to the pipe. you would have no changes in direction of the air flow  so it should be better. this contraption would need to be vertical though so the dust would fall into the bucket part  when you clean the filter

a lot of dust collectors use a ring between the filter and bag like the op is suggestion. im guessing that a lot of the losses  are cause by  that part . its basically a separator  but without the top and baffle .. the losses are from the change in direction and friction against the sides etc.  has any one ran test on their system to see where the majority of the losses are compared to stages of the build of a separator.

either way I agree with retired 2 that's its probably not worth it but you could always try and see  how it works

that should work. that 180 bend is going to increase resistance  . if you could put it straight into the second part it would work better. I think you will need a center pipe on the second seperater to make it spin properly