Aluminum chain?
 

Does anyone know if anybody makes aluminim chain? Our team is hurting for weight, and we've got alot of chain. Thanks

Re: Aluminum chain?
 

Do you know how much tension the chain might be under during operation? I don't know of any suppliers of aluminum roller chain, but several sources have plastic chain that's much lighter than typical steel. It is, as a result, also considerably weaker, rated for a tensile load of about 130 lbs. at best.

Try www.globalspec.com to find what you need. For plastic roller chain, Stock Drive Products (www.sdp-si.com) and W.M. Berg (www.wmberg.com) are the most common suppliers.

Re: Aluminum chain?
 

Are you using 25 chain or 35? If your using 35, switch to 25.

Re: Aluminum chain?
 

Thats a lot of work to completely switch chain types but if you have to do it, do it. Other options include cutting down the hubs of large steel sprockets, drilling holes in them and that route. I would stay away from plastic roller chain. Chain comes under a lot more force than you would think. i mean hundreds and hundreds of lbs of force. I'd do some calculations before you do anything radical like that. just as a headsup normal steel roller chain has a tensil strength of about 1050 lbs.

~Ian

Re: Aluminum chain?
 

In my opinion cutting down hubs s more work than changing chains of equal pitch!

Re: Aluminum chain?
 

Our vote is for cutting down sprockets... as long as you have a lathe..
We cut a few holes in our sprockets and turned those big heavy hubs down and literally cut pounds off of our robot... example
an 18 tooth sprocket weighed 2 lbs when we started and ending up weighing 1 pound !!! and that was JUST turning down that thick hub ...
I even did it!!! and I am only a physics teacher!!!

LOL

Bob

Re: Aluminum chain?
 

Well, what if there already running hubless sprockets?

Re: Aluminum chain?
 

Steel 60-tooth sprocket for #35 chain as delivered straight from the vendor, with honkin' big solid steel hub: weight 34 ounces.

Steel 60-tooth sprocket for #35 chain, following some lathe-enabled surgery to remove the hub and some milling to add some decorative "negative space" (i.e. lightening holes): weight 7.6 ounces.

Four sprockets on the robot, net weight reduction of 97.6 ounces.

Time required: about an hour per sprocket on a manual lathe and mill (or a similar amount of time with a strong-willed rookie team member armed with a hack saw and a lot of blades :) )

Cost of removing 6.1 pounds from the robot: priceless.

In other words, there is a lot of weight in the way, just waiting to be cut away and removed from your robot. You are likely to realize larger weight savings with this method that by replacing the chains (or, if you are in really bad shape, you may need to do both).

-dave

Re: Aluminum chain?
 

Again what if your runninnig hubless sprockets?

Re: Aluminum chain?
 

Well, here's some things we did to cut off on wieght:

1) Not only did we turn down our hubs, but we put holes in the sprockets. Now it looks like something from american choppers :D .

2) Replace all of your steel rods with aluminum rods. Doing this will reduce the wieght of all of the rods by 33%.

3) We used the 2x4 beams. We swiss cheesed them. By strageicly and CAREFULLY placing holes, we cut about 2 lbs off of out bot.

4) Tires are wieght, too. To also help with friction problems, we took our pneumatic tires, took off the tire and tube, and replaced it with pool hosing. This loses about 3/4 lbs per wheel, and greatly reduced friction for you out there with skid steering.

5) We put everything on boards. only our electrical board used it's entire surface. We cut the excess off of other boards and lost about 1 -2 lbs.

Just in case you were wondering, we were 14 lbs over. We're pretty close to being in spec now. One other useful tip would be to point your fans downward for a bit of extra lift :D (jk).

Hope this helps.
~Bstem

Re: Aluminum chain?
 

I believe it would reduce your weight to 33% of what it was with steel beams, not reduce by 33%.

Re: Aluminum chain?
 

I would not reccomend mounting any wheels or anything you expect to put a lot of torque/force on with aluminum shafts. A person can bend a 3/8" aluminum shaft by hand, just think of what a robot moving at 10 fps will do to it! :ahh:

Cory