[madmangt]

Now that I have a couple simple pneumatic props under my belt, I am quickly wanting to expand! (or course!) So I have seen several props with people that are clearly using a rotary pneumatic device to make a fast spin. Not having seen one of these for sale, I went to ebay and found some that looked like they may fit the bill but were upwards of $100 or more each (ouch). Does anyone have any sources or more information on where to find these and what I should look for?

 

[FearingtonHouse]

Depending on how far you want to rotate the item, a regular (straight & cheap) cylinder could still work. You could get a good 120 degrees or more of rotation with proper placement of a cylinder on a lazy susan rotation table. The method that I'm thinking of: lay the cylinder on top of the lazy susan and drag the bottom of the cylinder away from the circle table until the threaded tip of the cylinder rod touches the outside perimeter of the circle. If you were to attach the tip at that point and activate the cylinder, it would spin the lazy susan. Adjust the angle of the cylinder to change the rotation amount. Clear as mud?

 

[bfjou812]

Unfortunatly the rotary cylinders are expensive even used . There is a website www.robives.com that has some other ideas depending on what you're trying to do.

 

[EviLEye]

As bfjou812 said, they're pretty expensive even as used ones. I looked for a few months on Ebay and was shocked to see the bidding wars for various units. I eventually got 2 and didn't realize how small they were. One ended up going back as it was a 90* instead of the advertised 180* that I wanted. I had found myself downloading product PDFs to check functionality but overlooked double checking the sizes and the one I have easily fits in the palm of my hand. The other problem I was seeing is that it looked like it was going to be a PIA to attach something to the rotating cylinder.

I too looked into using a lazy susan with a cylinder. They have metal lazy susan's at Home Depot that are like $6 and can hold something like up to 250 pounds (they look like what's used on the underside of a bar stool). Unfortunately I just ran out of time given all of the other stuff I was doing.

 

[jandjbarry]

It's all about shopping on the off season and putting in the EBay time... lol I'm not rich I can tell you that so I'm always looking for deals...

The 2 rotary ones I have in the first pic are different in how they work... They are both 180 degree turn but the long one on the right has screw in each end that allow you to adjust it from 90 degrees to 180 differently on each side. Very handy for custom head movements and the like.

The second pic was a deal I had to try but I don't know what to do with... it's a 90 degree turn AND 6" lift cylinder in the same cylinder... very weird... no idea what to do with it...

I find now (if you look at the last 2 pics) that I'm designing props around cylinders now since I apprently was an Ebay addict back in 2005 and collected all this stuff I'm just now thinking about using... those long ones are all 3 footers and the short is a 4" bore for a HEAVY lift.

When it comes to rotary ones be patient and start early... the deals are out there...

Cheers!

 

[madmangt]

Great insight, guys! I will keep my eyes peeled but maybe explore the lazy Susan route as well.

 

[bourno]

I've had good luck with this type of rotary actuators



I have gotten some Vane rotary actuators previously, but didn't have good luck with them as the used ones seem to have bad sealing and couldn't use them with much force.

 

[Russell]

RE: Expensive (ouch) --- I hear that a lighter wallet lets you run faster and jump higher : - ) I've posted this before (I got to build some NEW stuff) but here goes - Examples of rotary cylinder in action: http://www.snydercentral.com/halloween/baby1.htm http://www.snydercentral.com/halloween/Baby2/Baby2.html
Also previously posted: How I restricted a non-adjustable cylinder:

 

[bfjou812]

The second pic was a deal I had to try but I don't know what to do with... it's a 90 degree turn AND 6" lift cylinder in the same cylinder... very weird... no idea what to do with it...


I would think something along the lines of a trash can trauma, the head comes up looks left then right then straight ahead starts speaking then downwould be pretty cool. You would need some limit switches and other hardware but it could be done.

 

[Pumpkinhead625]

AS&S sells two different sizes of lazy susan turntables :

http://www.sciplus.com/p/LAZY-SUSAN-TURNTABLE-BEARING-4_359

 

[EviLEye]

In Pumpkinhead's post, I have the 4" one and that was the one I was playing around with using plywood and a cylinder.

Russel and I have exchanged messages in the past and we both had ended up with the same unit that leaked air (grrr). Pictures can be deceiving as some of these things are pretty small. I used to think the one in Russel's post was much larger until he originally posted that pic a while back.

I agree though that the off season is probably the time to be looking cause it sure looked like a lot of people were bidding for 180* actuators. I can see why though cause a new SMC actuator can be $600 and up.

 

[Russell]

I had the tub of actuators out so I took some more pics for size comparison. My second baby prop leaked so I replaced it with a AGI model AGR-1 $45 on EBay. It worked so well the voices in my head told me I needed 5 more for a new prop. 1 for the neck, 2 for shoulders, and 2 for elbows. We'll have to see how that turns out. Please be warned that I and a lot of guys I've talked with have had problems with leaking rotary air cylinders. Please hold me harmless if you get an AGI cylinder thats junk but so far I have had good luck with them. They are small (they can go inside props) and not appropriate for spinning a large prop. I like the lazy susan idea for that.

 

[madmangt]

Jeez Russel! That's great info! It sounds like you have cornered the market for these! Hah! Those do indeed look smaller than I anticipated.

BTW that prop would be priceless for some sort of fast food drive through prank!

 

[bfjou812]

Please be warned that I and a lot of guys I've talked with have had problems with leaking rotary air cylinders


A lot of times when you buy used parts you will have problems, when air cylinders start leaking the o-rings and seals are usually worn and need replacing. The majority of manufacturers sell rebuild kits that include all the parts you would need . Sometimes the rod that actually carries the load will wear and start leaking or worse destroy the housing if neglected. I see in the picture of cylinders there is one labeled "leaks by design" ,could you please explain what you are refering to? I have found some locally at a good price , along with an assortment of rebuild kits and other parts, but if it is always leaking air it won't be very usable to me.

 

[Russell]

Please be warned that I and a lot of guys I've talked with have had problems with leaking rotary air cylinders


A lot of times when you buy used parts you will have problems, when air cylinders start leaking the o-rings and seals are usually worn and need replacing. The majority of manufacturers sell rebuild kits that include all the parts you would need . Sometimes the rod that actually carries the load will wear and start leaking or worse destroy the housing if neglected. I see in the picture of cylinders there is one labeled "leaks by design" ,could you please explain what you are refering to? I have found some locally at a good price , along with an assortment of rebuild kits and other parts, but if it is always leaking air it won't be very usable to me.

There are 2 pins on the side (the pins are in a safe unknown location at this time so I used wire in the photos) that go in and out as the top plate rotates. It leaks where the pins stick in. The pins are pushed by pistons. Maybe it needs new piston rings. Until I took it apart this morning I was thinking that air pushed the pins and that's why I said "leaks by design". It could be I got a bad one.

 

[Russell]

I just thought of something else. WARNING - When bargain shopping pay attention to the ports. I have found great deals on pneumatic devices only to find out later that the special adaptor to get air into it is hard to find and/or expensive. I have also got into situations where I buy the fitting to go from some exotic thread to 1/4 tubing and then found the ports are too close together to use the fitting : - (

 

[bfjou812]

Check this out , it is the PHD website, this is a breakdown of the cylinder, I don't see any pins in the drawing, I wonder if you are missing the adjustable stops ? Or they are part of the stop assembly? I didn't see them in your picture?


http://distributor.phdinc.com/Repla...B-AB&Product=Rotary_Actuator&Series=Series RF

 

[Russell]

Check this out , it is the PHD website, this is a breakdown of the cylinder, I don't see any pins in the drawing, I wonder if you are missing the adjustable stops ? Or they are part of the stop assembly? I didn't see them in your picture?


http://distributor.phdinc.com/Repla...B-AB&Product=Rotary_Actuator&Series=Series RF

LOL - Man! You made me work. I'm pretty much a "try it and if it doesn't work, throw it in a tub and do something else" kind of guy. I have a lot of tubs.
From that link clearly someone had modified the one I have. I removed the "pin guides" and plugged the holes with 10mm bolts. No more leaks. Those plugs depending upon the length of the bolts could be used to adjust the rotation. Based on this I change my "avoid" to a "consider" recomendation.

 

[EviLEye]

Excellent Russell, I'll have to try plugging it cause I have that same model and the pins will go shooting out. I think they're used to interface with another device that provides monitoring and feedback so when the rotation is in one full direction the pin will likely push against a contact switch.

Regarding the various sized connectors...yup, got burnt on this pretty good. Ordered really nice SMC cylinders online (ebay) and got solenoids from China and in the end the connector thread pitches were everything but NPT. But, I found that SMC has some nice universal like connectors that can accommodate various threads. So it can go into metric or standard. Sometimes they'd leak a little so the shop said to put teflon tape on the threads and after doing that they were rock solid. I didn't want to have a bag of various type of threaded air connectors so these have worked out well.

 

[bfjou812]

Russell, If you look at the parts list you will see that there are stops that go where the pins were.