planer thicknesser port issue

[alan m]

hi there
i am setting up my duct work  adn i put my thickness planer on the end of my run (mostly to see if i could keep up.
welll it managed to keep the machine clear but half filled about 6 feet of pipe. bit of a problem. the planer has a 4 " port but the duct is 6". i cleared it out
i was thinking last night about it .
today i put a spare 6" y fitting on the end of the planer. i put a 6-4" reducer on both sides of it and a blast gate on one.
i figured that the 4" on its own was starving the pipe of air. so i opened the blast gate on the y and let in air to make up for that.
everything worked a dream.
i planed a 4 foot long piece of 3" wide ash  from 1.5" down to 1/4"
not even a small build up anywhere.

the machine is a planer thicknesser combo so the dust schoot flips up over the cutter  for thicknessing but stays down for surfacing. the y fitting works great for thicknessing but would be a pain for surfacing because there would be nothing to support the y


anyway. i want to upgrade the 4" port on the planer to 6" but also want to allow in the make up air .
im not sure how to go about it design wise.
the flip around part has a slot across it that is 12" long and 1" high (less than half the area of a 6" pipe).
there is a transition from that to 4". i was thinking of making another one similar but a 6" down to 12" by  just over 2"

i am afraid that all the air will flow through the open part and not through the schoot

if i put that y on the end of the duct i think a similar result will hapen because of all the resistance from the planer and flex hose


i will post a pic tomorrow if i can

anyone have any ideas

thanks alan

[phil (admin)]

I need a picture.   ???

[alan m]

pic hopefully.
forgot my camera so i got creative

[alan m]

what im thinking of doing

[phil (admin)]

I see what you're talking about now!

I think it would work, and even if it doesn't it isn't like you'd be out a lot of materials.  And even if it isn't perfect, you could fine-tune it, maybe add an adjustable damper to it somehow so you can either leave it 12 x 2, or choke it down to the point where it gets everything from the planer?

[alan m]

i will try it. i have nothing to lose.
thicknessing is ok because the y sits on the table but surfacing the y will be on the floor