Plastic whiskers on central spindle: Design Secrets Revealed

Now that the season’s over, it’s time to pry some design secrets out of the top teams.

There were a number of teams that had a central spindle that had plastic whiskers sticking out to move the orbit ball up the hopper.

What did you use for the whiskers? How did you mount them on the spindle? What different materials did you try? How well did they work out? If you had to do it again what would you do differently?

Some teams had a series of beater bars with whiskers, same set of questions: What did you use for the whiskers? How did you mount them? How well did they work out? If you had to do it again what would you do differently?

We used strip brushes from mcmaster. I believe we went with 3" long “whiskers”. We attached them using the mounting strips that mcmaster also sells and just screwing them into our ABS drum. After switching from foam, and later surgical tubing to brushes, our helix no longer had jamming or stalling issues.

I also want to say that we did get the idea for the brushes from 148’s video after pausing it and carefully investigating. Before the brushes we were having lots of issues with “dead” spots in our helix, so thanks 148 for posting that video.

We’re too darn lazy and cheap to do something like that (we did find the brushes offered by McM). The students played around with different stuff the first week, and discovered that flaps of shelving liner work pretty well, so we used a couple dollars worth of shelving liner with flat aluminum stock to hold it to the sewer pipe, the shelving liner has a flap about an inch wide on each side of the aluminum. No special ordering of parts…just some drilling and screwing, and it’s done.

we used pnuematic tubeing with zip ties in the ends…

works well(never jams)

One of our mentors works at an 80/20 and pneumatic place so we used pneumatic tubing stuff. Though, we didn’t have a central brush. We used them as rollers to take balls in and move them through the track. We used school colors =D

Team 1218 found 4" brushes from fit perfectly into the channel of 1" 8020 and gave us the right diameter for our 24" cylinder. We could alter the number of brushes from 1-4, control the stiffness and length of the brush material and could easily direct drive the 8020 core with a combination of Andy Mark transmission, CIM and a custom adapter. Dead simple, 100% reliable.

Our infeed roller used the hook side of Velcro, and it sure worked great.

One of the first things we did in build season was to try different materials on the orbit balls…and quickly discovered that the hook side of Velcro did cause noticable damage to the Spandex covering, so we decided not to use it, to avoid damaging the game pieces, as the rules say.

We used PVC rollers, with pneumatic tubing.

A VERY easy way to secure the tubing was to drill a whole just a tiny bit undersized in the PVC, then run a short fastener into the end of the tubing in the PVC (requires drilling a hole on the opposite side of the PVC to insert the fastener).

alternatively to save a little weight…

just drill a hole in each side at 90’ degreee angles and stick the tubing through both(they havent come out of ours at 550rpm)

and to power it easily, if your using 4’ PVC just screw a cleanout of the bottom and attach a 1’ square tube to a motor and slide everything in place

Team 1468 used pneumatic tubing from the KOP. The central spindle was a 1" square piece of 8020 tubing with holes drilled through it for the tubing. It was actually one long piece of tubing which was threaded continuosly from one end of the 40" long spindle to the other. This gave us loops sticking out of the spindle to push the balls up. We found that this worked out better than having small tubing sticking out. Tapping 1/4-20 threads into each end of the 8020 made it real easy to bolt on bearings to the spindle.