Really big sproket

[crazykid234]

Our team is hoping to use a 12" OD sproket, so far all the sprokets i've found only go to about 6" od. Is there a sproket out there that big? or should I just try to make a rough one on my own?

let me clarify, I need that sprocket in an inventor(6) file, sorry if i'm just blind and i can't find it on the other threads, but i'm looking

[Joel Glidden]

This thread might interest you.

-Joel

[Dick Linn]

You can probably find one, but it is more likely to be for a 420 size chain or larger. Various off-road go-karts and motorcycles are likely to use this larger size. They may also be available in aluminum to keep the weight down. You can also use an intermediate shaft with more sprockets if gearing down is what you want to do.

Try Azusa Engineering. They list up to 100 tooth sprockets in #35(hthttp://www.azusaeng.com/azusaline.html). Here's a 1-piece 72 tooth aluminum sprocket for #35: http://www.mfgsupply.com/m/c/AZT5313...ml?id=gDhaXDzL

Possibly try sprocketspecialists.com They list sprockets up to 72 tooth, but you have to fish around by the make of motorcycle.

I believe one of the West Virginia teams used a very large sprocket last year to make a 4WD 4 wheel steering 'bot last year.

[Joe Johnson]

If you follow the thread about "Who Needs Large Aluminum Sprockets?", you will see that I think that Azusa is a good source.

I don't think they make #35 sprockets 12 inches in diameter, but they are close. They make 94T sprockets which have a pitch diameter of a little more than 11 inches.

Hope this helps.

Joe J.

[yamo18]

FirstCADLibrary Here you can find Sprockets. There is an I-Sprocket where you can make the dimensions whatever you want. Hope this helps.

Bryan

[Rob Colatutto]

Originally Posted by yamo18

FirstCADLibrary Here you can find Sprockets. There is an I-Sprocket where you can make the dimensions whatever you want. Hope this helps.

Bryan

Keep in mind that the i-parts are only usefull if you can actaully buy (or manufacture) the part.

[crazykid234]

Originally Posted by yamo18

FirstCADLibrary Here you can find Sprockets. There is an I-Sprocket where you can make the dimensions whatever you want. Hope this helps.

Bryan

Thanks, but that was the first sproket I tried, and it only goes to 60 teeth, or about a 6" od, I need some thing twice that size, so unless someone can tell me how to make custom I-sprokets, that doesn't help much. thanks though!

[Solace]

Originally Posted by crazykid234

Thanks, but that was the first sproket I tried, and it only goes to 60 teeth, or about a 6" od, I need some thing twice that size, so unless someone can tell me how to make custom I-sprokets, that doesn't help much. thanks though!

is it necessary that this sprocket have continous motion?

I am assuming that you need a sprocket of this size so as to increase your torque for picking up a large arm of some sort. As a general rule, a large arm affixed to a robot will never rotate more than, say, 300 degrees. If this is the case, you don't need an actually sprocket.

If you make a large wheel out of plywood or aluminum, it will serve the same purpose. simply wrap the chain around it and pin it in place on the wheel. because the chain is actually attached to the wheel, it cannot rotate past a certain point, but that's ok if your arm can't go that far anyways. you can usually make something like this to give you about a turn and a half of rotation, so say 540 degrees (more than enough). it also gives you the freedom to make it any size you want, and its lighter cause you can make it out of something that weighs a lot less than steel.

[Ed Sparks]

Originally Posted by crazykid234

Thanks, but that was the first sproket I tried, and it only goes to 60 teeth, or about a 6" od, I need some thing twice that size, so unless someone can tell me how to make custom I-sprokets, that doesn't help much. thanks though!

Just add a line to the i-part table with the specs you want and it will be selectable when you insert i-sprocket in your assy.