# What size cylinder?



## joker (Sep 25, 2007)

Just curious what you size (bore/stroke) you guys/gals typically buy for your pneumatic props? I bought a 1" bore 18" stroke cylinder for my popup, but it was a last minute replacing a bicycle pump I decided was unsafe.

I'm thinking about buying some cylinders to play with in the off season, but I don't have any specific props in mind yet. I realize without specifics this is hard to answer, but when utilizing a 4-bar or scissor mechanism what range of cylinder is typically used.


----------



## DarkShadows (Feb 6, 2006)

1.5" bore usually does the job for me. 2" for heavy duty stuff like skelerectors or full skeleton lifters or barrel hoppers.


----------



## bourno (Jan 21, 2006)

I like having 1-1/2 to 2" bore cylinders with stroke from 5 to 8" on hand from ebay whenever I can get them cheap in a lot.


----------



## joker (Sep 25, 2007)

bourno said:


> I like having 1-1/2 to 2" bore cylinders with stroke from 5 to 8" on hand from ebay whenever I can get them cheap in a lot.


That's mainly why I was wondering. I see these lots of cylinders on ebay, but hate to buy them if they're not going to be useful.

Related but a little off topic...how do you determine the length of cylinder for say opening a lid? I want to split the lid of my coffin down the center and completely open it for an erector or or extender to pop out.


----------



## DarkShadows (Feb 6, 2006)

You can really use any stroke length cylinder, It just depends how you position it and how much force you want it to push.


----------



## nfmmalice (Nov 13, 2008)

as far as bore goes, I prefer the overkill method.

I buy all my Cylinders in 1.5 to 2", unless space is a SEVERE issue. I would rather have MORE pushing power when I need it, than not have enough.

As far as the Stroke on the Cylinder to open a Coffin lid, you can get away with almost anything, depending on how/where you mount your Cylinder.

From my exerience, the Closer tothe "lip" you mount the cylinder, the more stroke (but less bore) you need. the closer to the "hinge" you mount it, the Less Stroke (But Bigger bore) you need.

Anyone else have any input?


----------



## bourno (Jan 21, 2006)

On my half coffin, I used back to back L brackets for each door to add some strength. Believe I used a 3" stroke cylinder for each side, I think they were 1-1/4" bore cylinders and running the prop around 40 psi.

http://www.teambac.com/web_hall/half_coffin.html

Using a longer stroke cylinder as nfmmalice mentioned, you can get by with less force needed.


----------



## joker (Sep 25, 2007)

Nice....thank you very much for the link. That's exactly what I'm wanting to do!


----------

