Like a lot of woodworkers, I'm using PVC plumbing pipe in a central dust collection system in my shop. One drawback for this type of pipe is that the fittings are not designed for upwards of 1000 CFM air flow, and will introduce significant pressure drop to the system. Additionally, once you get up into 6 inch and bigger sizes, the fittings get expensive.
These factors led to designing and printing my own fittings for the DC system. Blast gates, elbows, and wyes. I tried to design these to minimize pressure drop, and to fit the PVC sewer & drain pipe directly, without additional adapter fittings. The fewer fittings, the better for DC performance.
This Thing is a blast gate for use with 4-inch PVC S&D pipe and 4-inch flex hose. The side toward the dust collector is designed like the hub of a S&D pipe fitting, so it fits directly on the end of 4-inch pipe. The side toward the tool is designed for a good fit with the flex hose, which in turn connects to the DC port on the WW tool.
Magnets are included to ensure the gate stays in it's selected open or closed position while the DC is running. This could be considered optional. So far I've only run this with the gate horizontal, so it may be okay without, but I wanted to make sure they didn't creep open or shut from vibration. This might even hold the gate in place in a vertical position where gravity is trying to pull the gate down, but I have not yet tried this.
Mounting bosses are included for a micro switch. Eventually I will wire the DC system to use the blast gates as switches to start and stop the DC as the gates are opened/closed.
There are three mounting holes on each side. I've mounted some gates using both sides, and some with one side, and even one-sided is sturdy enough.
Some additional material is needed in addition to the 3D-printed components.
20% with 100% in stress areas
I don't have the exact settings I used, but nothing was critical. There are no overhangs on the parts, so no support is needed. One key setup is 100% infill in certain areas where it will be stressed by mounting or where solid material is needed for screw threads. I added this with infill mesh blocks in Cura.
PLA is the only material I've printed with so far. Something tougher may be better. Time will tell if the PLA wears down from friction with the gate slide. It doesn't really need much strength, and I've dropped it on a concrete floor with no breakage, so PLA seems to be okay.
After printing, the two halves, two spacers, and the gate need to be assembled. It's best to assemble the halves and spacers with the gate in position to be sure there's enough separation for the gate to slide. I glued the pieces together with epoxy, then drilled out the holes to an accurate size, then added through screws and nuts.
The gate needs to be made with 1/4-inch material - I used two 1/8 sheets of tempered hardboard glued to to make 1/4" and with both smooth sides facing out for less friction.
Handles, in my case, were made from some 1" x 1" scrap I had, and mounted on the gate with screws going through the bottom handle then through the hardboard and into the top handle. These could be simpler or even omitted if magnets are not used to hold the gate in place.
The switch base, switch, and cover are attached with machine screws into threaded inserts. This was the first time I'd used heat set threaded inserts. There are installation tools available, but I found it worked well just to use a round soldering iron tip. Press it straight down on the insert with very little force, wait for the insert to heat enough that it sinks down into the plastic, then pull the iron away.