sprockets
 

I just wanted to get peoples opinions, which do you think is better, Aluminum, Steel, or Plastic sprockets?? My team is having a minor problem in agreeing ....Some want to use Steel (which I believe is over kill and if you are tight on weight its not a good idea.) and then some want to go with AL and or Plastic.

assuming you are talking about drive gears
i dont think steel is much of a problem as long as its not to big, aluminum would be the best , but i would never use plastic. it will break or strip out way to easily.if your budget allows it i would use the aluminum gears , evn though they are more expensive.

I would just cut out the idea of aluminum or steel sprockets. Because drive gears/sprockets are under constant force and stree during the match, you want to use steel or cast iron. It's heavy, I agree, but it is the best choice. Our team gets sprockets/chains/gears machined by Borg Warner people and realize they make 90% of the world's small car chains and 80% of the larger automobile chains... such schweet quality.

Steel is best. If you're willing to buy extras and replace them periodically, aluminum may be worth it if weight is that important. Never plastic. Never.

:)

Definately Steel.

Weight however is an issue, which is why you pump it full of holes. You can even lathe down the hub in many cases (since often it is not needed, or at least doesn't have to be as big as it is). Generally, we manage to cut at least half the weight off our steel sprockets (and some of the gears too).

the teachers, engineers, and some knowledgable students on my team (myself hopefully included) all shudder and spasm at the idea of plastics sprockets when we saw them in the big blue book. its scary, those things - in a 130 lb robot - that will be ramming into things at top speeds? AAHHHHHHHHAHHHHHHHHHHHHHHAHHHHHHHHHHHH ahh ah

lol. *pictures total annihialation as little bits of plastic shrapnel come flying out of a robot*
okay mabie thats a little overdramatic bot SAY NO TO PLASTIC

Aluminum is fine, and is a lot lighter. Racing go-carts and motorcycles use aluminum sprockets, and they have a lot more horsepower! Anyone know of a source for aluminum sprockets with a 5/8" bore?

Try Small Parts or Mcmaster Carr.. I would say look into Mcmaster Carr first.

If you mount, and use them properly, plastic will work just fine, at least for wheel driven robots. The important thing is how you transmit the load from the shafts to the sprockets. If you get the chance, stop by our pits and check out our plastic sprockets.

Cast iron? That is a little brittle and extremely heavy if I remember correctly. I think you may be refering to gears made of pressed powdered metal like the old chiaphua gear cluster. If you want a good idea of how hard that thing was, try to grind it off. The lathe wouldn't even scratch it.

Aluminum is just fine
 

We've used aluminum sprockets for the last couple years (manufactured on our shop's CNC). We've had no problems and saved (literally) pounds of weight vs. steel.

Just don't have 5 subsystems and the weight should be fine. We use standard issue (formed powedered metal?) black steel sprockets from SPI or McMaster.

SPI is way overpriced though.

plastic is good enough for me...
 

I don't want to change anyone's mind but I can tell you that I am using a LOT of plastic sprockets this year.

Plastic is not as strong as aluminum and steel, but in the right application with the right design, it can be better than metal.

Your mileage may vary...


Joe J.