DIY Vibrator

[Harry]

Putting the hole in the lid is a good idea, this way you could rotate it around to find where the sweet spot is if it even matters. I plan on casting the lid so it will also have the half round race, this way very little air will be able to pass the ball. I am not sure if this matters or not, it might be that just the air hitting the ball each time it makes a circuit is all it needs to keep going but I cant help thinking that by creating some pressure behind it the operation should be stronger with lower air consumption all things being equal.

[dallen]

only thing I can say is that it has already been engineered by someone thats smarter then me, and all of em that I have seen have the air exhaust on the same plane as the air inlet. I'm not really sure how one of them would behave with the air outlet being in the cover. guess we'll just have to drill a hole in the lid and find out.
if it doesn't work, won't take but a minute to plug the hole and drill a new one.

[Harry]

I often find these things engineered by professionals with plenty of room left for improvement That is the beauty of it though, it is easy to try out different approached when you are casting the parts Intuitively I am thinking the ball should pass the exhaust just before it gets in front of the inlet for the next boost around, this way the air pressure is helping the ball all the way around. Of course the exhaust is open to the incoming air the whole time anyhow so this pressure behind the ball probably does not even matter and it is the actual impact of the incoming airstream on the ball that does all the work.

[Nudge]

Ok is that a casting or a cad drawing

A vibrator like that would beat up on my poor lil 2 gal compressor

you need to make a tiny one with a 1/8th bearing in it..... that should be about the right size.

[dallen]

I often find these things engineered by professionals with plenty of room left for improvement That is the beauty of it though, it is easy to try out different approached when you are casting the parts Intuitively I am thinking the ball should pass the exhaust just before it gets in front of the inlet for the next boost around, this way the air pressure is helping the ball all the way around. Of course the exhaust is open to the incoming air the whole time anyhow so this pressure behind the ball probably does not even matter and it is the actual impact of the incoming airstream on the ball that does all the work.

Harry I think yor right there, its just that the engineers that I have worked with for the last thirty years don't leave you any fudge room, or I should say they don't leave anyroom for them to make the changes that normally have to be made on the stuff they engineer. I'm quite sure that the air exhausting out the side or cover plate will work find, and Like your statement in Red above I also belive that once the ball has entered the air stream that, that is what has the most effect on the ball.

A vibrator like that would beat up on my poor lil 2 gal compressor

you need to make a tiny one with a 1/8th bearing in it..... that should be about the right size. [/quote]

Nudge I think that you will be quite surprised at just how large of an air vibrator that your little air compressor will actually run, its now how big but how long it will run it that will give you a problem, But if you take one say in the 1/2" range annd run it at say 40 PSI you will get a fair amount of shake on your pattern board, Remember that your not out to try and ram the thing by vibration but to just loosen the Plate in the sand.

But it would be something to see one with a 1/8 inch ball in it. Guess I could fire up the 9X20 and mount the ball turner on it and knock out a say three inch ball to build one around, will have to get a 250 CFM compressor to run it with though.

[Harry]

Another thought I had was a slightly oval shaped race way. This would let the ball gain some momentum in one direction before reversing the direction on it giving a decidedly direction shake to the vibration.

On the 3", well I have a concrete vibrator that has some massive shake to it if I need that kind of power. I think this is getting into a point of diminishing returns where the apparatus gets so big and the power requirements go way up that another system makes more sense. Not sure where that point would be with these ball vibrators but thinking 3" might be getting close

I do an awful lot with a relatively small compressor. The key is in having storage, my big tank is 250 gallons and I also have a smaller 40 gallon tank right at my jolt/squeeze that is plumbed with a 3/4" line. Th 40 gallon tank has plenty of air to cycle the squeeze then slowly refills from the line to the larger tank. If you have room for it getting a big tank will really help reduce the cycling on a smaller compressor and allow you to do things that it would not otherwise keep up with like sand blasting or running high cfm air tools. Might not be able to run them for long periods but enough to get a job done.

[Nudge]

Got to work on the lathe last night and wipped a quick vibrator based in the one in the link. It is my take on the idea using what I had on hand.
I started with an old casting (it was left over from my gate opener) and turned it into a clean "puck".

I then changed to a homemade 1/2" 'bullnose' cutter to form the channel for the ball bearing to run in.

Image017.jpg (24.32 KiB) Viewed 4865 times

In this pic, you can see the components. The bolt (seen in the centre of the pic) goes down from the plate seen at the bottom of the pic.& into the bottom of the channeled piece. The piece of pipe at the top of the image is the air pipe (I'm sure this has some fancy name)... a pipe tail?

Image020.jpg (15.66 KiB) Viewed 4865 times

The ball bearing is a 3/8" one I found in my box of "junk".
Final product!

Image022.jpg (16.41 KiB) Viewed 4865 times

The little bit of testing I did showed me that it will will do the job, but I thought that it would have had a lot more shake than it has. The air outlet is a 1/8" hole just behind the inlet (the inlet is a 1/16" hole). I may have to try a 1/2" ball to see what that does

[dallen]

good to see that you got it to working, they really are quite simply devices.

[4cylndrfury]

Yeah, Id bet a larger ball, or a longer track (larger diameter) will produce more amplitude. But that is a good looking device Nudge, and it doesnt look like it took too long to whip up at all! Pretty good for a first try Id say!

[Nudge]

It took about an hour and a half to make. Most of that time was looking for the bits to make it machine time was only an hour, using a full round nose cutter is slow because of its surface area. The hose tail is a press fit and was easy it make, for that matter the entire thing was easy to make. So if I get a bit more time I might make a bigger one, I think the larger diameter is the key.