What kind of cylinders does your team stock?

[ThunderPorpoise]

I'm looking into purchasing some pneumatic cylinders for my team and I'm a bit swamped by how many options there are. What do your teams keep in stock for various tasks that you might need to accomplish? (In terms of Bore, Stroke, Double or Single Acting, etc.)

[MrForbes]

We "stock" the leftovers from previous robots, and the ones we bought for previous robots that didn't work out quite right. We find we usually use 3/4" bore by 1, 2, 3, 4, 6, 8" stroke, and we have a pair of 1.5" bore x 8" stroke that have been used in a few different robots.

[billbo911]

Originally Posted by MrForbes

We "stock" the leftovers from previous robots, and the ones we bought for previous robots that didn't work out quite right. We find we usually use 3/4" bore by 1, 2, 3, 4, 6, 8" stroke, and we have a pair of 1.5" bore x 8" stroke that have been used in a few different robots.

This is as close to exactly what I was going to say that I don't need to change anything.

[Chris is me]

Cylinders are really the kind of thing you order once you know your design, or at least know what you're prototyping. McMaster sells them so we can get them in a day or two, and for everything else we use cylinders from old robots. Generally always double acting, front and rear pivot mounting.

[AdamHeard]

Originally Posted by Chris is me

Cylinders are really the kind of thing you order once you know your design, or at least know what you're prototyping. McMaster sells them so we can get them in a day or two, and for everything else we use cylinders from old robots. Generally always double acting, front and rear pivot mounting.

Agreed. We let mcmaster (and Automation direct) stock them for us!

[Dave Campbell]

Feeling a bit spoiled as our main team sponsor is Clippard Instruments.... we stock every COTS cylinders, fittings, valves and tubing in their catalog. In addition, they hire students from my program and our team members to work for the company, custom making many parts for our machine....check them out here: Clippard

Yes, they are the same company that donate the Volume Storage Tanks to all FRC teams.
A true FIRST partnership in action!

[Mike Marandola]

We keep an assortment of double acting cylinders from 1/2" to 3" bore and 1/2" to about 12" stroke. We like to have at least two of each in case we need one on each side of a system. 225 gave us some small single acting cylinders at Midknight Mayhem so maybe we'll get a chance to use them this year. One thing that we need to work on is keeping clevises for all cylinder sizes in stock.

[Oblarg]

Originally Posted by Mike Marandola

We keep an assortment of double acting cylinders from 1/2" to 3" bore and 1/2" to about 12" stroke. We like to have at least two of each in case we need one on each side of a system. 225 gave us some small single acting cylinders at Midknight Mayhem so maybe we'll get a chance to use them this year. One thing that we need to work on is keeping clevises for all cylinder sizes in stock.

This.

You get three bimba cylinders every year in the KOP, so it doesn't take all that long to build up a collection. Clevises and pivot brackets, on the other hand, are a perennial issue.

A tip: Use a vise to knock out the pin that comes in the rear-pivot assembly of the bimba cylinders, and use a bolt instead. It's far more convenient.

[Qbot2640]

Originally Posted by Oblarg

...
You get three bimba cylinders every year in the KOP, so it doesn't take all that long to build up a collection...

One year, not needing any new sizes for our build, we chose a 2" bore 36" stroke cylinder as one of our three from the Bimba PDV. The thinking was, if we ever needed one that big it would cost a fortune. Plus it is great fun to use for my pneumatic sessions at workshops!

Last year, we used the PDV to get our shooter cylinders (.75 X 12) and Bimba's delivery was quick enough that it was not a problem for our build. We probably ordered them a week and a half into build season, and had them by week four.

[Oblarg]

Originally Posted by Qbot2640

One year, not needing any new sizes for our build, we chose a 2" bore 36" stroke cylinder as one of our three from the Bimba PDV. The thinking was, if we ever needed one that big it would cost a fortune. Plus it is great fun to use for my pneumatic sessions at workshops!

We've got one of those for exactly the same reason on 449. It's pretty much completely useless for FRC, but it's a fantastic demo piece.

Bimba is extremely generous with their donation. Depending on the cylinders you choose, you can get a few hundred dollars' worth of parts. Of course, don't just opt for the most expensive ones available - figure out your constraints first, then pick your cylinders to match. If you're not using cylinders and just want a good all-purpose size, ~1.5'' bore x ~8'' stroke is probably the size I've used most.

[IndySam]

Originally Posted by Oblarg

We've got one of those for exactly the same reason on 449. It's pretty much completely useless for FRC, but it's a fantastic demo piece.

Bimba is extremely generous with their donation. Depending on the cylinders you choose, you can get a few hundred dollars' worth of parts. Of course, don't just opt for the most expensive ones available - figure out your constraints first, then pick your cylinders to match. If you're not using cylinders and just want a good all-purpose size, ~1.5'' bore x ~8'' stroke is probably the size I've used most.

We got one Lunacy year just because. I love to use it for pneumatic training, especially for volume and capacity lessons.

Bimba has been a fantastic long time sponsor of FIRST.

[dradel]

Originally Posted by MrForbes

We "stock" the leftovers from previous robots, and the ones we bought for previous robots that didn't work out quite right. We find we usually use 3/4" bore by 1, 2, 3, 4, 6, 8" stroke, and we have a pair of 1.5" bore x 8" stroke that have been used in a few different robots.

Curious here... It was my understanding that parts that are used on a bot cannot be reused on a later bot if it is modified. Technically speaking wouldn't putting fittings into an air cylinder make it no longer off the shelf?

The way it was explained to us lends itself to just that. Same holds true for transmissions and such ( hence why we haven't gone with two speed trans yet)

[EricH]

Originally Posted by dradel

Curious here... It was my understanding that parts that are used on a bot cannot be reused on a later bot if it is modified. Technically speaking wouldn't putting fittings into an air cylinder make it no longer off the shelf?

Technically... Yes. But the cylinder can be restored to COTS by removing those fittings. Takes 5 minutes or less. (OK, maybe plugging the output ports too.) And then you put the fittings back in.

You could also reference R16 from the 2014 rules, covering an edge case.

To answer the original question... 1197 has a couple of 2" bore, 24"+ throw cylinders laying around the shop (one in original packaging!), in addition to the usual 3/4" and 1.5" bores in various lengths. The big cylinders are primarily useful for "Hey, who wants a strong, slow, and heavy air-hogging mechanism?"

[Chris is me]

Originally Posted by dradel

Curious here... It was my understanding that parts that are used on a bot cannot be reused on a later bot if it is modified. Technically speaking wouldn't putting fittings into an air cylinder make it no longer off the shelf?

...And then when you take them back off, it returns to being a COTS item.

Originally Posted by dradel

So by your reasoning a team could reuse cylinders, transmissions, compressor, swerve drive and so on if they disassemble then reassemble ?

If they are off the shelf items, with no modifications whatsoever, yes absolutely. Hundreds of teams reuse compressors every year.

If the swerve drive happens to be a bought product, and again if the parts are unmodified, it needs to be restored to an off-the-shelf state and then it can be reused.

Any custom made parts, any COTS parts modified by machining, anything you actually "made" cannot be reused. So this is why teams design and build new drive bases every year. But if both drive bases use Toughboxes, and they didn't add any mounting holes or otherwise change them, reusing is functionally identical to buying another. So to save teams money it's permitted to take those COTS Toughboxes and put them on a NEW custom drive base, for example.

Again, *any* modification (that isn't / can't be reversed) changes the part from COTS to a custom part and it cannot be reused.

All of this post assumes the 2015 rules are similar to the rules in 2014 and before.

[GeeTwo]

Originally Posted by dradel

Curious here... It was my understanding that parts that are used on a bot cannot be reused on a later bot if it is modified. Technically speaking wouldn't putting fittings into an air cylinder make it no longer off the shelf?

The way it was explained to us lends itself to just that. Same holds true for transmissions and such ( hence why we haven't gone with two speed trans yet)

Assuming this rule doesn't change drastically,

R76

All pneumatic COMPONENTS must be used in their original, unaltered condition. Exceptions are as follows:

tubing may be cut,
wiring for pneumatic devices may be modified to interface with the control system,
assembling and connecting pneumatic COMPONENTS using the pre-existing threads, mounting brackets, quick-connect fittings, etc.,
removing the mounting pin from a pneumatic cylinder, provided the cylinder itself is not modified,
labeling applied to indicate device purpose, connectivity, functional performance, etc.

then as we read it: if you modify a pneumatic cylinder enough to keep it from being used the next year, you can't use it this year either! I suppose you could go through the drill of removing and replacing fittings every year if you think that the inspectors could tell that the fitting or label had been there longer than a couple of months..