J. Phil Thien's Projects

about this 15 degree slope. you will only be able to get a length of 7.5" before the sides converge to a point and touch each other. so if you were to build a dbl high top hat your outlet will be very small

I got that can three yrs ago and i love it just being able to glance over at it and see the level inside the can best way to avoid risking sucking dust up thru system and clogging the  filter. i dump the can when dust level gets to stepped section the can just below the handles

i think if you had a wood lathe you could turn a cone then slice it into a parabola with a couple of rabbets on each side so it would fit into the drop slot would be ideal but thats to much work.

i see you have a rod inside the chamber that supports the drop slot baffle.if you are going to hook this up to a planer or jointer Id keep an eye on that rod and make sure it don't catch shavings and start a birds nest.i don't know what you used for the baffle but most people use 1/4" hardboard and don't use a support. if your rod is a threaded rod i would cover it with a piece of pvc or something that is really smooth and debur the cut edges.

i use 4" in and out of my top hat along with a homemade rd to rectangular transition and no bell-mouth and my outlet pipe is flush to the top.

as the air enters the top hat and starts its spiral to the drop slot it might help out to offset the outlet just a small amount so the bell-mouth will be further away from the incoming and by the time the dust has traveled 3/4 around the chamber it has dropped somewhat to be out of the vacuum from the bell-mouth.

just a thought

thats why i dont use a bell-mouth and my outlet is flush with the top   

i dont know

but with my clear trash can i can see the dust is spiraling all the way to the bottom along the sides of the can.

if you were to place some type of baffle below the gap it might disrupt the smooth flow and cause fines to become airborne and work their way to the outlet pipe.

to me mine works great the way it is and i am not going to reinvent the wheel since i don't have the tools to measure the amount of bypass since it would be on the micron level.

in all the yrs since i've built mine i've only got less than a half gallon of bypass in my bag below the filter and that's after i've blown air on the outside to clean the filter.

looking at your picture of the outlet pipe. it looks like you have a piece of particle board (or mdf) under the Masonite drop slot piece. the masonite should be beveled on the bottom side and sand the edges really smooth and round off the back edge of the slot where it stops and i would get rid of that piece of particle board (or mdf) or really cut it back from the edge of the masonite. i think if you had a larger drum you'd be better off.   

i tried using the bell mouth at halfway also lower and higher. i don't have any hard data but from my testing other than just my observation but i ended up not using the bell mouth and with the outlet flush with the bottom of the top. i did my testing with the table saw and the drum sander and watched what made it to the bag. six years later i have never had to empty the bag and there is less than a gallon milk jug  of dust in the bag.
i made this crazy thing with a 10" tire inner tube so i could play with setting.its been under the bench for yrs so its kinda dusty

i use an old opel car jack, some black pipe and flange fittings on each end and a piece of plywood for a platform. i have a plywood box around the jack so that when its lowered platform sits on box. platform is guided by the 4 black pipes and when its time to empty the drum it just slides off the platform and when i put it back there are is a half round shaped stop on platform to register the can in place then i crank the jack with my cordless. these are old pictures since then i have gone to the transparent trash can.
http://www.webstaurantstore.com/continental-3200cl-32-gallon-clear-huskee-trash-can/6902632CL.html?utm_source=Google&utm_medium=cpc&utm_campaign=GoogleShopping&gclid=Cj0KEQiA1NWnBRDchObfnYrbo78BEiQA-2jqBZzOkDUiVqd1-qWmeu9OcRuNqecreK_zhB1y-FZrV4waAm758P8HAQ

i  just use a 1/4" hard board that is beveled back on the bottom side. the slot where it meets the 120 degree section has radius on the end of slot and is smooth. when r2 was building his top hat i had suggested maybe bolting a rod to bottom of trash can so the baffle could rest against it. so thinking of your idea  maybe you could make a sleeve that fits over the rod but has a magnet in it to hold baffle in place and then you could remove it to empty the can. but i believe in KISS method and would just go with the proven method and use the hardboard. ive never had a problem with mine

the bag makes cleanup so much easier when it comes time to change bags, with the cloth bag you will need to transfer dust to another bag  (nasty job) or dump out in the back 40 acres.  Back when i used the 2 bag factory setup (delta 50-850) i would always get a puff of dust blowing thru the bags every time i started the DC  Now i use a tophat design by retired2 and a filter and in the past 5 yrs i have never had to empty my plastic bag.

in the first post you said "flat bid" what do u mean. dont quite understand what u mean by saying your using a 6.25 sq coming off the top. are you making a 2x tophat with side inlet (located at top) or are you trying to make a 2x height of the original thien separator with the 6.25 inside. post a sketch   

i would have to agree with r2 raise it inlet elbow up. it also looks like you never cut the side of elbow off to get more of a smoother flow against the inside of trash can. i cant really tell the position of your inlet elbow but thats why i really like the TH inlet comes in on a tangent which forces dust against inside of TH.
i cant believe you have so much dust in your bag i have never had to change/empty my bag in over 4yrs in all these yrs there is less than a half gallon in my bag (table saw,drum sander,13" dewalt planer with shelix head,drill press,wood lathe...). i also have a very transparent trash  can (older post) under my tophat and i can see the dust spiral down along the inside of the can. i had a bellmouth but i removed it and my out pipe does not extend into the TH chamber.

if you need a short section try looking at yard vac.
dont know the prices but they use bigger hoses.
here is a quick search i did. but i would do some more searching. maybe you could request a foot sample from a mfg.
http://www.trac-vac.com/index_files/manuals.htm
try looking at the 470 from dropdown menu

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hope this works