Auto-blastgate, working prototype *w/pics*

[Alan in Little Washington]

I was going to wait until I had a final version, but decided to go ahead and post pics of the prototype since it is close to a final design.

I picked up some 110V solenoid pneumatic air valves off Ebay. Like most on Ebay they had been removed from some automated machine and came in a block of 10 valves. This pic shows the valve block, one of my 6" manual blast gates, and a homemade cylinder. I subsequently abandoned the idea of making my own cylinders. The gates are operated by air pressure from my shop air- but only need about 20 psi.



These particular valves have threaded outlet ports on the back of the valve body, but the sides have open air passages. While two of the passages are for exhaust ports and can remain open, one passage is for the air supply, so I built covers from some scrap acrylic sheet. I drilled holes for the exhaust and pressure passages and mounting screws, and threaded the pressure passage hole for a fitting.






I purchased double acting cylinders, again from Ebay, made a bracket from aluminum, and mounted a cylinder to one of my blast gates. For testing, I mounted the valve to the front of my jointer just below the blastgate. The solenoid valve is activated by the machine power and controls shop air which then operates the cylinder. I still need to make some refinements, but as it is, it works great. Actuation time is less than 1/2 second using less than 20 psi and MUCH QUICKER with higher pressure. I will eventually shorten the air connection hoses, run permanent low pressure shop air lines, and add a micro switch to turn the DC on (but not off- I don't want it to cycle too quickly). Here are some pics of my freshly painted prototype autogate in action.

[Bas]

Dude!!!!

(Sorry, couldn't think of anything that would do this remotely justice. Awesome design and build....)

[Jim Kunzweiler]

Looks good. Should be a real convenience.

You can use shop air (90-120 psi) for your cylinders by adding a flow control or flow restricter in line with the cylinder. Flow controls are just needle valves (think old carburetors) that restrict the flow of air to the cylinder and will slow it down. I use them on cylinders I have on my clamping fixtures. Flow control valves can be had for less than $10 and are available on-line (http://www.aircylindersdirect.com/catalog/details/323 or MSC-direct.com)
In fact if you slow down the cylinder when it goes to close off the gate you would essentially be running your dust collector for a few seconds after the tool shuts off....clearing the line.

If you have the pipe taps and dies you can make your own inline restricters by drilling an inline orifice, maybe 1/64" to 1/32". With your cylinders and solenoids you will have to experiment to find the right orifice size.

Good luck with your project. Let us know how it works out when you get you gates fabricated.

[Makinsawdust]

Allan,
Now that's a piece of fine North Carolina Woodworker'er engineering. I wish I was so mechanically inclined. I was borned mechanically declined. Been that way since birth and probably will never over come it.
Rob

[NCPete]

Alan is the mad scientist among us!

[sediener]

That's pretty cool, how will it know which one to open?

[jtodd71]

Dude!!

[Alan in Little Washington]

Originally Posted by sediener

That's pretty cool, how will it know which one to open?

I will have a blast gate for each machine, powered by each machine. That way if I am using two machines at a time, like I do sometimes with the tablesaw and jointer, both blastgates will be open. Lazy me won't have to even think about opening a gate for just a quick cut- I almost never do- it will open automatically. Also, by having the gate turn the DC on, but not off, if I am jumping from machine to machine, which I also do, I don't need to worry about cycling the DC blower too often. When I'm done with whatever sequence of dust making operations, I'll just hit the off button on one of my wall stations located around the shop.

[Bas]

Originally Posted by sediener

That's pretty cool, how will it know which one to open?

Alan has a really big remote strapped to his back



Actually, it's magic. The machines sense what he wants to do, and open the corresponding gate. 40 years from now, a T1000 is going to come back in time to kill him for enslaving them.

[jsjordan]

All I can is "WOW! That is awesome!!"