A recent discovery and its major implications …
Is there any bearing material between the pieces of 80/20? Without that I foresee a lot of mechanical inefficiency in the system. Other than that it looks like you are doing a good job.
An elevator made out of 80/20 and #25 run inside the 80/20 to raise/lower it?
YES! We discovered that #35 chain fits almost perfectly between adjacent pieces of 8020. Add to that the fact that the steel-to-aluminum friction is very low, and you’ve got a very good thing.
We mounted two verticle pieces of 8020 to the drive train frame, and ran the chain down the slot to a “elevator car” that rides on two pieces of 8020 about 12" long. (There’s about 1/16" gap between the car and the rails, so there’s little side-to-side drag. ) The car is attached to the chain at the top and bottom, and the chain loops out the bottom via sprockets back to the top. Add a Barbie to drive the sprocket, and we’ve got a low friction high strength elevator!
Were thinking of doing something extremely similar to this. As this is only are 2nd year would you mind answering a few questions.
What size/type 8020 did you use?
How do you mount the sprockets to the end of the 8020?
Thanks.
Standard 1" x 1"; if you need the exact part number I can dig it up.
How do you mount the sprockets to the end of the 8020?
We bolted a piece of 3/8" lexan to the end of each 8020. The shaft for the sprocket goes through bearings which are mounted to the lexan. We used T-bolts to attach the lexan to the 8020, so we could slide the lexan (and therefore the shaft) to take up any chain slack.
Interesting. Looks like things are coming along.
How 'bout a quick vacuum of the robot frame? 
-Nick
Good idea! My only warning is that we used 80/20 in the past to build a forklift (2008) and unless everything is 100% lined up, you’re going to start building up a lot of friction. Given that we had quite a bit more on the end of the forklift though which contributed to the problem, I’d still watch out for friction, it’s a killer.
Your saving grace here is that the aluminum used for in 8020 is anodized. The anodized layer is very hard and wear resistant. Without this layer the aluminum would quickly gall and cause an immense amount of friction. I would definitely keep those slots greased or oiled in case the anodized layer starts to scrape off!
Another question. Do you have a chain on each side of the lift, and if so are both sides powered or does one side just free slide?
What motor are you planning to use. My team is planning to use either a fisher price or window for our motor, and we can’t decide.