Whew! It has been a while since I added anything to this. But it took a while to get this part right. I needed a way to steer the vacuum from the shopvac and Dust Deputy to either the table saw or the router table. Inspiration for this design came from here .
In principle the valve is pretty simple:
Just a flapper moved by a rotating shaft to steer the vacuum to one port and seal the other port off. To move the shaft I borrowed the design from the seed link above. I ordered a couple of 120 VAC solenoids and mocked the driver up on my bench to see how it worked. A scrap piece of MDF, two plugs from a hole saw leftover from another project and lots of rooting around in the junk box:
These tests went really well. This solenoid has some authority! The seller rated it at 3 lbs of force and I believe it. I made up all the pieces for the entire valve:
And here is the solenoid driver with shaft in its new home:
When finished there will be a 2” cavity for the solenoid and moving parts. This will get a cover to keep fingers out of the moving parts and away from the hot solenoid. This solenoid is rated for continuous duty but, when I left it activated for 20 minutes, it did get hot.
I made a quick jig to remove part of the shaft to hold the flapper at the router table. There must be a better way to do this! I ended up making 3 shafts to get one good one. The shaft kept tearing out at both ends of the cut.
And here is the flapper, simply a piece of 3/16 plywood, installed:
I epoxied weather stripping onto the flapper to get better seal:
Getting a good seal on both ends of the flapper was the hardest part of this project. When I drilled the holes for the shaft, I centered it in the valve cavity. When I made the flat for the flapper to attach to the shaft I felt that centering the flapper in the shaft would weaken the shaft too much. So the flapper ended up offset from the centerline of the shaft by quite a bit. I should have offset the holes for the shaft to compensate for this.
In the end, I used a round nose router bit and routed two channels in one side of the cavity to compensate for the flapper offset.
I epoxied pieces of 2 inch PVC pipe for connection to standard 2 1/2 inch vacuum hose:
In the picture above, you can see the relief I routed to compensate for the flapper offset.
And here is the completed valve:
Next up: the Control Box.
-- "Find out what you cannot do and then go do it!"