Where to find aluminum sprockets?

We are in a bit weight trouble, so we want to swap some of our mcmaster sprockets out for aluminum ones. Does anyone know any website who sells aluminum sprokets for half inch shaft that has around 20 teeth? We cannot find any, but we remember some place back in 2008 where we got it. We need hubs on these sprockets.

Thanks a lot for helping us.

Andymark sells aluminum sprockets

We looked at those, but we would like some aluminum sprockets with hubs. The ones on Andymark do not have hubs if there are more than 12 teeth. We would like around 20

Hubs can be made with the right equipment.

Some more details about exactly what type of sprocket you need could help. Not all vendors carry every type of sprocket.

Our team does not have CNC or milling machines, so it will be hard for us to machine a hub.

We need ANSI 35 chain sprockets, around 20 teeth, Half inch shaft, perferrably 1/8 key way or set screw is acceptable too

We already looked on Robotmarketplace, Andymark, McMaster and Grainger, are there more websites selling these kinds of parts?

AndyMark sells hubs too.

But what about this plus this?

You do not need a milling machine, or CNC equipment, to make a hub. All you really need is a drill press. Having a lathe might make things easier, but it is not absolutely necessary.

I’ve got to say that I don’t have any specific recommendations for vendors as I’ve never searched for that particular part - But one thing to consider is how much weight you can actually save by doing this, and “weigh” that in comparison to the amount of time/effort/money it may take to find, and then swap out, the aluminum sprockets. Unless you have a lot of them of your robot, it may not provide a significant reduction in weight (If you only have, say, 8 sprockets on your drivetrain). You may want to look into some other places to cut weight, such as switching to lighter bolts (or using rivets), or removing/lightening any nonessential parts, or using thinner materials. There are plenty of threads about other ideas for making your robot lighter (Like using the new(er) plastic pneumatics tanks, as opposed to the metal Clippard tanks -if you’re even using pneumatics. That’s just one idea though). However, if you do decide its worth pursuing to switch the sprockets, best of luck in finding hubs/sprockets that will work for you!

Thanks, we only needs to swap 6 sprockets out, but we are currently using the McMaster stainless stell black finish sprockets, they are HEAVY, so yeah, we can save about 2 pounds by swaping all of them out, we are only 3 pounds overweight at this points. We did place an order on those plastic tanks and new compressor to save weight, but we would like to be a bit safer, you know just in case

I take it your robot uses live axles on drive? Dead axles would allow you to mount the sprocket to the wheel directly, saving more weight and allowing many of the existing aluminum sprocket options…but I’m assuming you’ve made your choice and are running with it in this regard.

Going with the AndyMark sprockets and hubs together is probably the easiest solution, though you may also be able to lighten your existing ones with a little swiss cheese in a desperation move. (Do that carefully, of course.)

You could also run your compressor off-board, which could drop a couple of pounds easily if you can run your matches with your tanks pre-charged.

Okay, gotcha. Then if you’re that close on weight and already making some other amends, trying to switch those sprockets out does seem reasonable (and I’m impressed/surprised it adds up to 2 pounds, that’s pretty significant!). The new compressor and tanks really do help by a lot though (likely more than one pound, quite possibly even off-setting the three that you are over). However, making yourself a pound or so underweight couldn’t hurt, right? Ya never know what will come up during competition.